November 28, 2023 - MWRA Advisory Board

U.S. Environmental Protection Agency · from the EPA · 179 pages · 1.7 MB
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Advocacy & Accountability 
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mwraadvisoryboard.com 
Matthew A. Romero
Executive Director 
November 28, 2023 
Michele Barden 
U.S. Environmental Protection Agency –
Region 1 
5 Post Office Square, Suite 100 (06-1) 
Boston, MA 02109 
barden.michele@epa.gov 
Claire Golden 
Surface Discharge Program 
Massachusetts Department of Environmental
Protection 
150 Presidential Way 
Woburn, MA 01801 
massdep.npdes@mass.gov 
RE: Comments on Draft Permit No. MA0103284 for the MWRA Deer Island Treatment Plant 
Dear Ms. Barden and Ms. Golden: 
The Massachusetts Water Resources Authority Advisory Board (the Advisory Board or the Board)
appreciates the opportunity to comment on the draft National Pollutant Discharge Elimination System (NPDES)
Permit No. MA0103284 (the Draft Permit) for the Massachusetts Water Resources Authority (MWRA) Deer
Island Treatment Plant (DITP). The U.S. Environmental Protection Agency – Region 1 (EPA or the Region)
noticed the Draft Permit for comment on May 31, 2023. That same day, the Massachusetts Department of
Environmental Protection (MassDEP) also issued a 2023 Draft Massachusetts Permit to Discharge Pollutants to
Surface Waters for DITP (the State Permit) that incorporates by reference Parts I.A-K and Part II of the Draft
Permit. This letter similarly comments on the State Permit. 
The Advisory Board, formed by the same legislation that created MWRA, represents and submits these
comments on behalf of the communities served by MWRA. 1 MWRA ratepayers live in those communities and
bear the costs associated with operating DITP and MWRA’s sewer system. The Draft Permit attempts to
regulate four of these communities (Boston (through the Boston Water and Sewer Commission (BWSC))),
Cambridge, Chelsea and Somerville) that own and operate combined sewer systems (the CSO-responsible Co-
permittees), and thirty-nine communities that own and operate sanitary sewer system (the Co-permittees). 2 
The Advisory Board harbors substantial concerns about how the Draft Permit (and, by extension, the
State Permit) would inappropriately regulate DITP and the communities. The Draft Permit relies on generic
prohibitions against violating water quality standards that, contrary to law, fail to define how MWRA and the
communities must assure the protection of receiving water quality. The inclusion of forty-three communities as
co-permittees exceeds EPA’s authority in several respects and, in many instances, is inadequately explained in
the Fact Sheet. Turning DITP’s permit into a quasi-regional general permit for collection systems also creates
the risk that the communities could incur liability for conduct for which they are not responsible. Unless EPA
and MassDEP clarify the communities’ and MWRA’s responsibilities, DITP’s permit could upset the
longstanding and successful relationship among MWRA and the communities. 
The Advisory Board also has substantial concerns about the Draft Permit’s imposition of novel
requirements to develop and implement major storm and flood event plans. These requirements mark a 
1 See Acts of 1984 ch. 372, § 23, 1984 Mass. Acts 805. 
2 Those thirty-nine Co-Permittees are listed in pages 1-4 of Appendix B to the Draft Permit and in Appendix B to the State Permit.

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Matthew A. Romero
Executive Director 
momentous change in NPDES permit requirements and have the potential to burden the communities’ budgets
and capital planning processes. Yet Neither EPA nor MassDEP has provided much of any explanation for these
major new programmatic requirements. Moreover, both agencies have failed to explain how they have statutory
authority to impose long-term resiliency planning and capital project implementation obligations through this
permit. 
This failure to identify legal authority is unsurprising because none exists. These planning requirements
attempt to regulate facilities and assets untethered to any specific discharge, are inconsistent with the NPDES
permit’s five-year term and the certainty Congress intended to afford NPDES permittees. In addition, EPA has
failed provide permittees and the general public with a cost-benefit analysis of these novel and substantial
requirements, which will take far longer than the 12-month deadlines that the Draft Permit gives MWRA and
the communities to develop and begin to implement major storm and flood plans. EPA should also assess
whether communities’ existing planning efforts address or could be adapted to address the issues EPA seeks to
remedy through the major storm and flood event planning requirements in the Draft Permit. 
Finally, requirements for permittees and co-permittees to develop adaptation plans that have appeared in
NPDES permits issued subsequent to issuance of the Draft Permit suffer from many of the same legal
infirmities identified above with respect to major storm and flood event planning. 
I. The Draft Permit’s Generic Prohibitions Against Violating Water Quality Standards Violate
the Act and EPA’s Regulations. 
The Draft Permit’s vague, open-ended requirements to meet water quality standards (WQS) without
specifying how MWRA and the communities are supposed to do so violates the Clean Water Act (CWA or the
Act). Rather than prescribe concrete pollutant limits or operational requirements to protect water quality, Parts
I.A.2, I.B.2.a, and I.B.2.f (collectively, the Generic Prohibitions) make water quality standards directly
enforceable against MWRA and the CSO-responsible Co-Permittees. In doing so, the Generic Prohibitions will
force MWRA and the communities to guess about how to meet applicable water quality standards, all while
remaining exposed to an after-the-fact enforcement action if EPA or a citizen plaintiff disagrees. 
The Act and EPA’s regulations do not allow the Region to place MWRA and the communities in this
untenable position and the Generic Prohibitions must be removed from the final permit. To the extent that
permit terms in addition to technology-based effluent limitations (TBELs) are needed to attain WQS, 3 the CWA
demands that NPDES permits set limitations—distinct from the WQS themselves—that the Agency has
determined to be adequate to protect WQS. Consistent with the statute, the NPDES permitting regulations
require the Region to translate applicable WQS into concrete permit limits rather than make them directly
applicable to dischargers. The Generic Prohibitions are also inconsistent with the Combined Sewer Overflow
(CSO) Control Policy , 59 Fed. Reg. 18688 (Apr. 19, 1994) (the CSO Policy), which specifically requires permit
writers to derive permit limits to protect water quality using EPA’s regulatory process for translating WQS into 
3 The Advisory Board supports the use of narrative—rather than numerical—TBELs for the CSOs authorized under the Draft Permit
as described in MWRA’s separate comments.

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Matthew A. Romero
Executive Director 
discharger-specific limitations if limits in addition to TBELs are needed. Retaining the Generic Prohibitions in
the final DITP permit would violate these requirements. 4 
A. The Act Does Not Allow EPA to Make Water Quality Standards Directly Enforceable
Against MWRA and The Communities. 
The Region’s inclusion of the Generic Prohibitions in the Draft Permit disregards its obligation under
the Act to tell MWRA and the communities how they must control their discharges to ensure attainment of
WQS. Section 301(b)(1) of the Act requires EPA to set “limitation[s] … necessary to meet water quality
standards.” This language draws an explicit distinction between “limitations” that EPA may impose in permits
and the WQS they protect. The Generic Prohibitions, however, erase this distinction by making whether
receiving waters meet WQS the basis for determining whether the Permittee and Co-Permittees are complying
with the Permit. The Region may not ignore the Act’s directive to protect WQS using concrete “limitations” by
making WQS directly enforceable. 
To the extent that the Region believes the Generic Prohibitions are necessary to ensure the attainment of
WQS, they are also incapable of serving this function and invalid under the CWA. In NRDC v. EPA , the
Second Circuit invalidated a provision in the Vessel General Permit that—like the Generic Prohibitions—
imposed a general duty to meet applicable WQS. 808 F.3d 556, 568 (2d Cir. 2015) (permit required control of
discharges “as necessary to meet applicable water quality standards in the receiving water body”). The court
found that a general mandate not to violate WQS “is insufficient to give [dischargers] guidance as to what is
expected or to allow any permitting authority to determine whether a [discharger] is violating [WQS].” Id. at
578. This lack of guidance—a failure to specify pollutants limits or other specific requirements—led the court
to conclude that the generic prohibition failed to meet the Act’s “requirement that NPDES permits ensure
compliance with the CWA.” Id. at 580. The Generic Prohibitions provide no guidance to MWRA or the
communities as to how they must protect WQS, such that they suffer from the same failure to provide direction
that was fatal to the Vessel General Permit. 
B. The NPDES Permitting Regulations Do Not Allow the Region to Abandon Its Obligation to
Set Discharger-Specific Limits Translated from WQS. 
By imposing the Generic Prohibitions, EPA also failed to follow its own rules that prescribe only one
mechanism for NPDES permits to supplement TBELs to protect water quality standards: setting discharger-
specific water quality-based effluent limitations (WQBELs). See 40 C.F.R. § 122.44(d)(1)(i)-(vii). Under those
regulations, EPA must follow a two-step process for setting limits to protect water quality: 
• First Step : Determine whether a WQBEL is needed by conducting a reasonable potential analysis.
This analysis entails an assessment of whether discharges, taking into account existing permit limits
and other sources of pollution, “will cause, have the reasonable potential to cause, or contribute to an 
4 EPA and MassDEP have also failed entirely to explain or justify the Generic Prohibitions’ inclusion in the Draft Permit and State
Permit, respectively. Neither the Fact Sheet nor the Supplemental Fact Sheet explain the reason for the Generic Prohibitions’
inclusion or how either agency possesses authority to impose them. In failing to do so, both agencies violated their obligations to
explain the legal and substantive basis for permit terms. See 40 C.F.R. § 124.8 (fact sheet must include a summary “of the basis for
the draft permit conditions including references to applicable statutory or regulatory provisions and appropriate supporting references
to the administrative record.”); 314 CMR 2.05(3)(c) (fact sheet must include a “brief summary of the basis for the draft permit
conditions including references to applicable statutory or regulatory provisions”).

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Matthew A. Romero
Executive Director 
excursion above any State water quality standard ….” 40 C.F.R. § 122.44(d)(1)(i). This analysis
entails characterization of “both the effluent discharged by the facility … and the receiving water for
that discharge,” and often involves modeling or using other analytic methods that must be
documented in the record. EPA, NPDES Permit Writers’ Manual ( “NPDES Manual”) pp. 6-12, -30
(Sep. 2010). 
• Second Step : If reasonable potential exists, the permit writer develops one or more WQBELs for
pollutants that could cause WQS exceedances. The regulations direct permit writer to set each
WQBEL at a level that is “derived from, and comply with all applicable” WQS. 40 C.F.R. §
122.44(d)(1)(vii)(A). EPA guidance specifies that deriving and setting a WQBEL requires an
analysis of data and other relevant information. See NPDES Manual p. 6-35. 
The CSO Policy, which the Region is obliged to follow in writing the Draft Permit’s provisions
addressing combined sewers, 5 makes clear that EPA must follow this process when it sets limits in NPDES
permits that regulate CSOs. In writing a Phase II permit like the Draft Permit, the Policy requires the Region to
supplement the permit’s TBELs by writing WQBELs “under 40 C.F.R. 122.44(d)(1),” the regulation that
requires EPA to conduct a reasonable potential analysis and derive discharger-specific limits. CSO Policy §
IV.B.2.c., 59 Fed. Reg. at 18696. The Policy further expects that these limits will be not be open-ended
mandates. See id. 
The region’s proposal of the Generic Prohibitions, however, reflects a failure to follow the CSO Policy’s
and regulations’ requirement that they follow these procedures for setting WQBELs if limits beyond the
permit’s TBELs are required. The record is devoid of any analysis—or any substantive justification
whatsoever—identifying the need for the Generic Prohibitions. The Region conducted no reasonable potential
analysis to support these broad prohibitions, nor are they in any way “derived from” applicable WQS. The
Region has done no analysis or other work to translate WQS into a discharger-specific limit, which is what
EPA’s guidance has long understood deriving a WQBEL to mean. In total, the Region’s inclusion of the
Generic Prohibitions reflects a failure to heed its permit writing obligations concerning water quality. 
C. The Generic Prohibitions’ Inclusion in the State Permit is Inconsistent with MassDEP’s
Regulations. 
For these reasons, MassDEP’s incorporation of the Generic Prohibitions in the State Permit violates the
regulations for Surface Water Discharge Permits. MassDEP may not issue a permit if its “conditions … do not
provide for compliance with the applicable requirements of … the Clean Water Act … and the NPDES
regulations at 40 CFR Part 122.” 314 CMR 3.07(1). The Draft Permit, as explained above, runs afoul of the
CWA’s and the NPDES regulations’ requirement to protect WQS using only concrete, discharger-specific
permit requirements. 
The Generic Prohibitions’ inclusion in the State Permit further conflicts with MassDEP’s obligations
under its own regulations to the extent that MassDEP believes they are necessary to protect WQS. MassDEP
may not issue a permit in instances where “the imposition of conditions cannot ensure compliance with the
applicable water quality requirements in all affected States.” 314 CMR 3.07(4); see also 314 CMR 3.11(3) (“all
permits shall contain limits which are adequate to assure the attainment and maintenance of the water quality 
5 See 33 U.S.C. § 1342(q)(1).

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Matthew A. Romero
Executive Director 
standards ….”). As explained above and as held by the Second Circuit, the Generic Prohibitions’ lack of
concrete requirements for protecting water quality make them—per se—incapable of meeting this requirement. 
MassDEP also failed to comply with its regulations’ requirements for considering site- and discharger-
specific information when setting permit limits to protect water quality. The regulations command MassDEP to
set permit limits to protect water quality after taking into consideration “natural background conditions, existing
discharges, the protection of existing downstream uses, and the attainment and maintenance of beneficial uses
in downstream waters.” 314 CMR 3.11(3). The Generic Prohibitions circumvent these mandatory analyses by
making WQS directly applicable to dischargers. MassDEP cannot rely on these broad, vague provisions to
shirk its obligations to set tailored limits that apprise MWRA and the communities of their compliance
obligations. 
II. Inclusion of Sanitary Sewer Communities as Co-Permittees 
For the first time, EPA and MassDEP are attempting to regulate the thirty-nine sanitary sewer
communities by subjecting them to regulation under DITP’s permit. This radical change to these communities’
regulatory obligations exceeds both agencies’ authority and, as explained in Section IV below, threatens to
disrupt the longstanding relationships between MWRA and the communities it serves. The agencies have also
sought to impose this new regime without the communities’ consent by unlawfully waiving their permit
application requirements. 
More troublingly, MassDEP has provided no explanation for its decision to regulate the Co-permittees
under the State Permit. The Supplemental Fact Sheet supporting the State Permit provides no justification at all
for MassDEP’s decision to regulate the sanitary sewer communities as Co-permittees. MassDEP has an
obligation to provide a “summary of the basis for the draft permit conditions including references to applicable
statutory or regulatory provisions” in its fact sheets but has provided none for including these Co-Permittees in
the State Permit. 314 CMR 2.05(3)(c). In order for the Advisory Board and the communities to have an
adequate opportunity to comment on the State Permit, it is critical that MassDEP explain its reasons for this
major action and open a new comment period. 
A. The Agencies’ Lack of Jurisdiction to Regulate the Communities 
1. The Federal Draft Permit 
The Draft Permit’s inclusion of the sanitary sewer communities as Co-permittees exceeds the Region’s
jurisdiction. The Act and case law limit EPA’s authority under the NPDES program to regulating “the
discharge of [a] pollutant.” 33 U.S.C. § 1311(a). In the absence of such a discharge, these communities are
“neither statutorily obligated to comply with EPA regulations for point source discharges, nor are they
statutorily obligated to seek or obtain an NPDES permit.” Waterkeeper Alliance, Inc. v. EPA , 399 F.3d 486,
504 (2d Cir. 2005); Nat’l Pork Producers Council v. EPA , 635 F.2d 738, 751 (5th Cir. 2011) (“There must be
an actual discharge into navigable waters to trigger the CWA’s requirements and the EPA’s authority.”). 
The communities’ conveyance of flows downstream to DITP, however, is not a discharge that triggers
EPA’ jurisdiction. A regulated discharge requires an “addition of any pollutant to navigable waters from [a]
point source ….” 33 U.S.C. § 1362(12)(A); 40 C.F.R. § 122.2. The communities’ sanitary sewer systems,
however, add no pollutants to navigable waters. Instead, they add pollutants only to MWRA’s treatment works,
as EPA concedes in the Fact Sheet. Fact Sheet 20 (“The Massachusetts municipalities in Appendix A own and

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Matthew A. Romero
Executive Director 
operate wastewater collection systems that discharge flows to the DITP ” (emphasis added)). The only addition
of pollutants to navigable waters occurs far downstream, when DITP discharges treated effluent from Outfall
T01. 6 
EPA’s rules reinforce the conclusion that the communities do not have discharges that trigger the
Region’s CWA authority. The regulatory definition of a “discharge of a pollutant” explains that the term
encompasses releases “through pipes, sewers, or other conveyances owned by a State, municipality, or other
person which do not lead to a treatment works ….” 40 C.F.R. § 122.2. This language would only be necessary
if the obverse is true: flows conveyed through municipally-owned sewers that do lead to a treatment works are
not discharges. 
The handful of cases holding “that persons who discharge pollutants through conveyances owned by
another entity may be subject to NPDES permit requirements” provides no cure of EPA’s lack of jurisdiction. 
In re Charles River Pollution Control Dist. , 16 EAD 623, 636 (EAB 2015). In each of these cases, the alleged
discharges passed through point sources that were not treatment works and provided no treatment prior to
discharge. 7 By contrast, the communities’ flows receive treatment at DITP—a treatment works—prior to
MWRA discharging to Massachusetts Bay. Under the Act and EPA’s regulations, the communities’ flows are
not discharges that EPA may regulate. 
2. The State Permit 
For these reasons, MassDEP regulation of the Co-permittees in the State Permit is inconsistent with the
regulations governing Surface Water Discharge Permits. The Surface Water Discharge Permit regulations, like
CWA, generally tie their permit requirement to persons who “discharge pollutants to surface waters ….” 314
CMR 3.03(1). And much like the federal program, the regulations define a “discharge” as an “addition of any
pollutant to waters of the Commonwealth,” and explain that a discharge includes “discharges through …
sewers, or other conveyances owned by a … municipality … which do not lead to a POTW.” 
The sanitary systems’ conveyance of flows to DITP involves no addition of pollutants to any waters of
the Commonwealth. They add flows only to the downstream POTW, a circumstance that the regulations
indicate is not a discharge that requires a permit. 
B. The Co-Permittees Cannot Be Regulated by Deeming Them Part of the Same POTW as
DITP. 
1. The Federal Draft Permit 
6 The Region’s assertion that satellite sewer systems’ lack of proximity to the “the ultimate discharge point is not material to the
question of whether it ‘discharges’” is inconsistent with the Supreme Court’s interpretation of the Act. Fact Sheet, Appendix D at 13.
In County of Maui v. Hawaii Wildlife Fund , the Court explained that “[t]ime and distance traveled are obviously important” to
determining whether a regulated discharge has occurred. 140 S. Ct. 1462, 1476 (2020). 
7 See United States v. Ortiz, 427 F. 1278, 1280 (10th Cir. 2005) (discharges conveyed through a storm sewer); San Francisco
Baykeeper v. W. Bay Sanitary Dist. , 791 F. Supp. 2d 719,769-70 (N.D. Cal. 2011) (sanitary sewer overflows discharged through a
storm sewer); United States v. Velsicol Chem. Corp. , 438 F. Supp. 945, 946-47 (W.D. Tenn. 1976) (alleged discharges conveyed
through a storm sewer).

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The Region cannot cure its lack of jurisdiction by lumping the sanitary sewer communities in with the
larger facility—the publicly-owned treatment works (POTW) that includes DITP—covered by the Draft Permit. 
8 EPA’s regulations define a POTW to be “a treatment works … which is owned by a State or municipality —
expressed only in the singular. 40 C.F.R. § 403.3(q) (emphasis added). Similarly, the definition uses only the
singular to refer to “the municipality … which has jurisdiction over Indirect Discharges to and discharges from
such a treatment works.” Id. (emphasis added). This deliberate use of the singular means that a POTW can
only be owned by a single municipality, such that the communities’ sewer systems cannot be part of same
POTW as DITP. 
The regulatory definition of a “discharge” confirms that the Region has improperly expanded the
definition of POTW to span multiple communities’ sewer systems. That definition covers “discharges through
pipes, sewers, or other conveyances owned by … a municipality … which do not lead to a treatment works.”
40 C.F.R. § 122.2. If a satellite collection system could be part of a POTW, there would never be circumstance
where a municipally-owned sewer could “lead to a treatment works.” Instead, this provision would refer to
municipally-owned sewers “which are not part of a treatment works.” The Region’s attempt to make the Co-
Permittees part of the same POTW as DITP cannot be reconciled with its own regulations. 
Even if the Co-permittees’ systems were part of the same POTW as DITP, this conclusion would not
empower EPA to regulate these communities in the absence of a discharge. When a facility requires an NPDES
Permit, the Region’s authority extends only to its actual discharges. See NRDC v. EPA , 859 F.2d 156, 170
(D.C. Cir. 1988) (“the CWA does not empower the agency to regulate point sources themselves; rather, EPA’s
jurisdiction … is limited to regulating the discharge of pollutants.”). Even if the communities’ sewers systems
were part of the same POTW as DITP, EPA lacks authority to regulate their non-discharging activities. 
2. The State Permit 
MassDEP similarly cannot deem the communities’ sewer systems part of the same POTW as DITP
under its permitting regulations. The Surface Water Discharge Permit regulations—like their federal
counterpart—define a POTW by reference to a single public entity rather than several. See 314 CMR 3.02
(“any device or system used in the treatment … of municipal sewage … which is owned by a public entity .”
(emphasis added)). Having chosen to define a POTW by reference to a single owner, MassDEP cannot include
satellite systems owned by thirty-nine communities in the same POTW as DITP. 
C. Permit Application Requirements Cannot Be Waived In Toto. 
Even if EPA and MassDEP could regulate the Co-permittees in DITP’s permit, issuance of a permit to
thirty-nine communities that never submitted permit applications would violate their respective permitting
regulations. EPA’s rules specify that “[a]ny person who discharges … must submit a complete application ….”
40 C.F.R. § 122.21(a)(1). The Region then “shall not issue a permit before receiving a complete application for
a permit ….” Without any permit applications from the sanitary sewer communities in hand, EPA cannot issue
a permit imposing conditions on them. 
8 See Fact Sheet, App’x D at 10 (EPA may regulate satellite communities because they are part of “facilities subject to the NPDES
program”); id. (“NPDES regulations similarly identify the ‘POTW’ as the entity subject to regulation.”).

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EPA may not sidestep this limit on its authority by waiving application requirements for the Co-
permittees. See Fact Sheet 12, 21. EPA’s March 8, 2023 letters to the sanitary sewer communities claimed that
40 C.F.R. § 121.21(j) authorized the Region to waive permit application requirements in their entirety. See 
Attachment A (Sample Waiver Letter). The Region’s waiver authority under this provision, however, extends
only “to any requirement under this paragraph [ i.e. , the POTW-specific requirements in § 122.21(j)].” 40
C.F.R. § 122.21(j). Thus, EPA only could have waived discrete information requirements for treatment works,
not the fundamental requirement that a regulated entity submit a permit application. Accord 64 Fed. Reg.
42434, 42440 (Aug. 4, 1999) (“EPA proposed the introductory paragraph of § 122.21(j) to allow the Director to
waive any requirement in paragraph (j) ” (emphasis added)). The Region violated its own regulations by
attempting to waive the sanitary sewer communities’ obligation to submit applications. 
MassDEP similarly violated its regulations by seeking to regulate the Co-permittees in the State Permit
without having received permit applications from them. The Surface Water Discharge Permit rules specify that
“[a]ny person required to obtain a permit … shall complete and submit the appropriate application form(s).”
314 CMR 3.10(1); see also 314 CMR 2.03(1) “Any person required to obtain an individual permit … shall
apply to the Department.”). MassDEP then “shall not issue a permit before receiving a complete application
….” 314 CMR 3.10(4); see also 314 CMR 3.02(2) “The Department shall not issue an individual permit …
before receiving a complete application.”). 
Under this framework, MassDEP cannot issue a permit that regulates the Co-permittees. None of them
have submitted applications for Surface Water Discharge Permits. MassDEP’s regulations, moreover, do not
offer the department any authority to waive permit application requirements. 
III. Inclusion of Combined Sewer Communities as CSO-Responsible Co-Permittees. 
A. Failure to Justify the Combined Sewer Communities’ Inclusion. 
The Draft Permit and State Permit take the momentous step of making BWSC, Cambridge, Chelsea, and
Sommerville CSO-responsible Co-permittees without their consent or any substantive justification. Rather than
explain the decision to include these communities in the Draft Permit, the Fact Sheet simply declares that their
inclusion implements a “general practice … to integrate treatment plant and connected CSO authorizations into
a single permit.” Fact Sheet at 109, 128. The Fact Sheet, however, provides neither documentation nor
examples of this so-called practice, particularly in situations where the treatment plant and combined sewers are
operated by different municipalities or authorities. 
Additionally, Appendix D provides no justification for the CSO-responsible Co-permittees’ inclusion in
the Draft Permit. The document only addresses co-permitting sanitary sewer systems. See, e.g. , Fact Sheet
Appx. D at 4-7 (discussing sanitary sewer systems at length). Additionally, its central justification—that co-
permitting satellite sewer systems is necessary to ensure that they are controlled under NPDES permits—is
inapplicable to combined sewer systems. See, e.g., id. at 17 (“the addition of the satellite systems as co-
permittees is necessary to ensure collection system operation and maintenance”). The CSO-responsible Co-
permittees have historically been regulated under individual NPDES permits, and the Region has provided no
explanation for why combining their permits with DITP’s is beneficial to the four CSO-responsible Co-
permittees, the environment, or the general public. Without any explanation in the Fact Sheet, the Advisory
Board and its member communities lose a meaningful opportunity to comment on the Draft Permit.

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Executive Director 
The Supplemental Fact Sheet supporting the State Permit provides even less justification for MassDEP’s
decision to consolidate the CSO-responsible Co-Permittees’ authorizations into DITP’s permit. MassDEP has
an obligation to provide a “summary of the basis for the draft permit conditions including references to
applicable statutory or regulatory provisions” in its fact sheets. 314 CMR 2.05(3)(c). Having provided none for
including the CSO-responsible Co-Permittees in the State Permit, MassDEP has deprived the Advisory Board
and the communities of a meaningful opportunity to comment on the State Permit and violated its regulations. 
It is particularly critical that the agencies justify their decisions to force BWSC, Cambridge Chelsea, and
Somerville into a co-permittee arrangement because this action departs from EPA guidance on writing permits
for CSOs. Since 1995, EPA guidance has allowed permit writers to regulate under a single NPDES permit
treatment plants and combined sewer systems (named as co-permittees) operated by different municipalities.
EPA, Combined Sewer Overflows – Guidance for Permit Writers p. 2-8 to-9 (Sep. 1995). The guidance,
however, cautions that “[s]uch co-permittee arrangements are subject to consent by the respective co-
permittees.” Id. at p. 2-9. The agencies must either obtain the CSO-responsible Co-permittees consent to being
covered under the Draft Permit and State Permit or explain why they have decided to depart from longstanding,
national guidance on this issue. 
B. EPA’s Regulations Do Not Allow the Region to Consolidate the Combined Sewer
Communities’ NPDES Permits with DITP’s. 
In addition to being inadequately explained, the Region’s inclusion of the combined sewer communities
in the Draft Permit is inconsistent with EPA’s permitting regulations. The NPDES permitting rules allow for
the consolidation of permit applications, but only under specific circumstances: (1) “[w]henever a facility or
activity requires a permit under more than one statute,” or (2) “whenever a facility or activity requires permits
from both EPA and an approved State ….” 40 C.F.R. § 124.4(a)(1), (c)(2). 
These circumstances do not exist here. The Region is attempting to consolidate multiple federal permits
all issued under the same statute, rather than consolidate permits issued under multiple statutes or multiple
jurisdictions. Moreover, the combined sewer communities’ CSOs are not part of the same “facility or activity” 
as DITP. These discharges are distinct from DITP’s and are not, by definition, part of the same POTW as
DITP. See Montgomery Envt’l Coalition v. Costle, 646 F.2d 568, 592 (D.C. Cir. 1980) (EPA appropriately
interpreted the definition of treatment works to exclude CSOs). 
IV. The Draft Permit and State Permit Do Not Define the Responsibilities of MWRA, the CSO-
responsible Co-permittees and the Co-permittees with Adequate Clarity. 
Even if EPA and MassDEP could lawfully structure DITP’s permit to include both the CSO-responsible
Co-Permittees and the Co-Permittees, neither the Draft Permit nor the State Permit define these parties’
obligations with clarity sufficient to ensure that they are not held liable for conduct or events over which they
have no control. The Advisory Board appreciates the attention that the Region has dedicated to this issue, as
evidenced by the language appearing at the beginning of Part I.E.2 and the Region’s invitation for comments on
“the clarity of the several liability of” MWRA and the communities. Fact Sheet 21. 
The Draft Permit and the State Permit, however, are not sufficiently clear about MWRA’s and the
communities’ respective responsibilities and the potential liability that would flow from non-compliance. Part
I.B and the Draft Permit’s cover page, for instance, do not explain that MWRA and the CSO-responsible Co-

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Executive Director 
permittees are severally liable for their own activities and sewer systems. For example, one community should
not be liable for another’s failure to implement its Nine Minimum Controls, but the Draft Permit does not make
this clear. Attachment B contains proposed revisions to the Draft Permit, including the cover page and Part I.B,
that provide adequate clarity concerning MWRA’s and the CSO-responsible Co-permittees’ respective
responsibilities and liabilities. 
The cover page and Part I.E.2 must also be revised to provide MWRA and the communities with
absolute clarity that MWRA is not responsible for the communities’ noncompliance and vice versa. Any final
permit issued by EPA and MassDEP must make clear that the communities cannot be held liable for violations
of permit requirements applicable to DITP; the Draft Permit and State Permit fail to do this. Language in Part
C, Part D, and Part E must also be clarified further to remove any ambiguity regarding the several liability of
MWRA, the CSO-responsible Co-permittees, and the Co-permittees. Attachment B contains proposed revisions
to the Draft Permit, and Attachment C contains proposed revisions to the State Permit to resolve these
remaining ambiguities. 
It is particularly critical that EPA and MassDEP clearly delineate these responsibilities to avoid
disrupting the longstanding relationship between MWRA and the communities, and among the communities
themselves. Each community and MWRA have their own responsibilities with respect to wastewater treatment,
and collection system management and compliance. 9 Under its organic statute, MWRA must be accountable to
the communities, rather than a manager or regulator of the satellite sewer systems it serves. An NPDES permit
or Surface Water Discharge Permit that could make MWRA liable for the communities’ conduct—or vice
versa—could threaten that relationship. 
Even if MWRA and the communities did not have this unique relationship, basic principles of fairness
would demand that the agencies avoid confusion over MWRA’s and the communities’ respective obligations
and liability. Noncompliance with an NPDES permit can result in both criminal and civil liability under federal
law, and even private actors can sue to enforce an NPDES permit. 10 See 33 U.S.C. § 1319 (providing for
federal enforcement of NPDES permits); id. § 1365 (providing for citizen enforcement). Against this backdrop,
EPA’s guidance for permit writing specifies “[e]ach permit must be written clearly and unambiguously so that
compliance can be tracked effectively and the permit can be enforced if violations occur.” NPDES Manual p.
11-21. 
V. EPA Should Eliminate or Significantly Modify the Draft Permit’s Major Storm and Flood Events
Planning Requirements. 
As representatives of the ratepayers subject to climate change challenges, the Advisory Board
understands the need for resilient practices to address those challenges. The Advisory Board has long
advocated for policies and practices that are both environmentally sound and ratepayer equitable – “Green and
Fair.” To that end, we look forward to working with state and federal regulators and other stakeholders to
address climate preparedness in a technically-sound, legally-compliant, and economically-fair manner. Our 
9 See Acts of 1984 ch. 372, § 26(d), 1984 Mass. Acts 809 (each local body served by MWRA has “the charge and control of the
respective water, waterworks and sewer works owned and used by said local body and not in the ownership, possession and control of
[MWRA].”). 
10 Failure to comply with a Surface Water Discharge Permit can similarly result in civil and criminal liability under the Massachusetts
Clean Waters Act. See M.G.L. c. 21, § 42.

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shared goal is protecting invaluable public resources while providing affordable, reliable wastewater and sewer
services into the future. 
That said, Part I.E.1.a and I.E.2.(e)(2) (the Major Events Planning Provisions) of the Draft Permit
impose novel and onerous long-term obligations to develop and implement resiliency plans that would
effectively highjack the communities’ long-term planning efforts and burden their capital budgets. Far beyond
requiring adequate operation and maintenance of existing facilities and sewer systems, these new provisions
could require permittees to relocate existing assets or even construct new ones. 
Part I.E. requires MWRA and the communities to prepare major storm and flood events plans for their
wastewater treatment facilities and sewer systems, respectively, that will culminate in implementation of
mitigation projects. These plans, which the Draft Permit requires to be updated every five years, must include
(1) an asset vulnerability evaluation; (2) a systematic vulnerability evaluation, and (3) a mitigation measures
alternatives analysis, and they must take into consideration future conditions, “specifically the midterm (i.e., 20-
30 years) and long-term (i.e., 80-100 years) and, in the case of sea level change, the plan must consider sea level
change.” Draft Permit Part I.E.1.a, 2.e.(2). The Draft Permit requires that these plans will be implemented and
contemplates that they will materially impact MWRA’s and the communities’ capital budgets. See, e.g. , Draft
Permit at 35 n. 16. 
The Advisory Board would expect that such a momentous, potentially burdensome new program would
be well explained and amply justified in the Fact Sheet and Supplemental Fact Sheet. It is not. To be clear, the
Advisory Board understands and appreciates the importance of addressing climate change and its impacts on
Massachusetts communities and beyond. But those efforts must take place within the appropriate statutory and
regulatory frameworks. 11 In announcing these new programmatic requirements, EPA has provided only a
conclusory justification, and MassDEP has provided none. In order to give the Advisory Board and the
communities an informed opportunity to comment, the agencies need to explain how they have statutory
authority to impose the Major Events Planning Provisions. In addition, the Advisory Board and the public
deserve a cost-benefit analysis of these novel and substantial requirements, which will take far longer than the
Draft Permit’s 12-month deadlines to develop and implement. Finally, EPA should assess whether existing
planning efforts address or could be adapted to remedy the issues EPA seeks to address through the Major
Events Planning Provisions. 12 
A. The Fact Sheet Provides Inadequate Support for These New Programmatic, Capital
Planning Obligations. 
In announcing new requirements that will impact MWRA’s and the communities’ planning and capital
budgeting processes, EPA and MassDEP failed to provide the public with the information they need to make 
11 For example, EPA cites to a recent City of Leominster riverbank stabilization project as an example of the process that EPA
envisions for plans to address climate change through the addition of these new requirements. Response to Comments, NPDES
Permit No. MA010818 at 8 (Sept. 27, 2023). While that project may prove helpful in addressing climate change impacts, it is not a
project undertaken as an NPDES permit requirement. That project took place under a FEMA Hazard Mitigation Grant Program that
the municipality used to protect a main sewer line it had identified as vulnerable to flooding and failure. Id . For the reasons set forth
herein, requiring capital improvements of this type would be inappropriate in an NPDES permit, and there are other programs more
well-suited for those changes. 
12 Such an assessment would also help EPA and MassDEP articulate to the public what is missing from the Fact Sheet and
Supplemental Fact Sheet: the objectives and basic reasons for creating this new program in DITP’s permit.

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informed comments. In writing a fact sheet, EPA must address “the significant factual, legal, methodological
and policy questions considered in preparing the draft permit.” 40 C.F.R. § 124.8(a). With respect to the Major
Events Planning Provisions, the Fact Sheet falls far short of meeting this requirement, offering only conclusory
assertions that these new planning and mitigation project requirements are needed “to ensure the proper
operation and maintenance of” of DITP and regional sewers. Fact Sheet at 102-03. 
These conclusions cannot be squared with the Draft Permit’s requirements and leave the reader to
wonder what “factual, legal, methodological, and policy questions” EPA considered when it developed these
new risk mitigation provisions. The Major Events Planning Provisions go far beyond “proper operation and
maintenance” of a treatment plant and sewers; they call for the potential to relocate facilities or even build
entirely new infrastructure. EPA’s justification cannot support the requirement it seeks to impose. 
The Fact Sheet’s terse explanation also leaves the public to wonder what methodological and policy
questions informed EPA’s decision to create these new planning obligations. Among other policy questions and
factual issues, EPA must explain why NPDES permits are the appropriate vehicle for imposing climate change
resiliency requirements on regional sewer systems, why the plans must consider long-term risks as far as 100
years out (more than twenty times longer than the term of any NPDES permit), and why plans must consider
“extreme sea level change.” EPA’s regulations require it to address these and other important policy and
methodological issues associated with these burdensome new planning obligations. The agency has failed to do
so here, thereby depriving the Advisory Board, the communities, and the public of a meaningful opportunity to
comment on these new permit terms. 
MassDEP similarly failed even to provide the cursory explanation that the Fact Sheet offers. The
Supplemental Fact sheet provides no explanation for why MassDEP believes it would be appropriate to impose
these planning and implementation obligations in Surface Water Discharge Permit. By failing to do so,
MassDEP violated its own obligation to describe “the significant factual, legal, methodological and policy
questions considered in preparing the draft permit.” 314 CMR 2.05(3). 
B. The Draft Permit’s Major Events Planning Provisions Improperly Regulate Facilities and
Assets, Not Discharges. 
The Fact Sheet also fails to explain how the CWA authorizes EPA to use an NPDES permit to impose
planning obligations that could culminate in MWRA or the communities having to relocate infrastructure or
even build new facilities. In its cursory explanation for these new programmatic obligations, EPA does not
once cite the statute or describe how the CWA empowers the agency to impose these wide-ranging
requirements as part of the NDPES program. See Fact Sheet 101-03. 
The Advisory Board can only surmise that EPA provided no explanation because the CWA does not
authorize the Major Events Planning Provisions. The CWA allows NPDES permits to impose only those
conditions necessary to ensure compliance with the CWA’s requirements for discharge quality. 13 Courts have 
13 See 33 U.S.C. § 1342(a)(2) (limiting EPA authority to impose permit requirements to those terms “that assure compliance with the
requirements of paragraph (1) of this section,” referring to 33 U.S.C. §§ 1311, 1312, 1326, 1317, 1318, and 1343).

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repeatedly held that the CWA limits EPA’s authority to only regulating discharges; EPA cannot use NPDES
permits to regulate other aspects of a discharging facility. 14 
The Major Events Planning Provisions, however, reach well beyond EPA’s authority to regulate
discharge quality. The Draft Permit’s provisions for broad ranging evaluations of asset location and
vulnerability—and the implementation of potentially costly capital projects to address them—has no apparent
relationship to assuring compliance with applicable effluent limitations. Moreover, the Major Events Planning
Provisions even contemplate that MWRA or the communities may need to construct “remote locations” or
“[r]elocate facilities to higher elevations.” Draft Permit Part I.E.2.e.(2)i.(c)(ii), (iv). Such requirements at their
heart seek to regulate MWRA’s and the communities’ facilities (and capital planning processes), not their
discharges. EPA’s authority to issue NPDES permits does not extend this far, and the Major Events Planning
Provisions should be removed from any final permit. 15 
EPA cannot cure its lack of authority to impose these major storm and flood event requirements by
invoking 40 C.F.R. § 122.41(d) and (e). See Fact Sheet 101. These regulations do not confer on EPA authority
it otherwise lacks, and nothing in either regulation authorizes a permit writer to impose the types of long-term
planning and capital project development that the Major Events Planning Provisions impose. 40 C.F.R.
§122.41(d) requires a permittee to take all reasonable steps to minimize or prevent any discharge in violation of
the permit with a reasonable likelihood of adversely affecting human health or the environment. This provision
applies only where there is a discharge in violation of the permit, which is not at issue here. 
40 C.F.R. § 122.41(e) similarly cannot support the Draft Permit’s attempt to require MWRA and the
communities to develop and implement plans that may ultimately necessitate, among other things, the relocation
of existing infrastructure or the construction of entirely new facilities. This provision imposes an obligation
only to operate and maintain the equipment and systems a permittee uses to comply with its NPDES permit.
Nothing in that regulation authorizes EPA to direct a permittee to undertake capital construction projects or
relocate equipment or systems that it uses to comply. Rather, that rule directs permittees to maintain equipment
and systems they use to comply with express terms of their NPDES permits. 16 EPA’s attempt to use this narrow
regulation to justify requiring permittees to acquire or build new systems and equipment, perhaps in locations
far from existing facilities or assets, simply cannot withstand scrutiny. 
14 See Waterkeeper All., Inc. v. U.S. E.P.A ., 399 F.3d 486, 505 (2d Cir. 2005) ((“[T]he Clean Water Act gives the EPA jurisdiction to
regulate and control only actual discharges—not potential discharges, and certainly not point sources themselves.”); Natural
Resources Defense Council v. EPA, 859 F.2d 156, 170 (D.C.Cir.1988) (“[T]he [Clean Water Act] does not empower the agency to
regulate point sources themselves; rather, EPA’s jurisdiction under the operative statute is limited to regulating the discharge of
pollutants.”); see also Iowa League of Cities v. E.P.A ., 711 F.3d 844, 877 (8th Cir. 2013) (“effluent limitations are restricted to
regulations governing ‘discharges from point sources into navigable waters.’” (citing 33 U.S.C. § 1362(11))). 
15 The Major Event Planning Provisions are also improper to the extent they will intrude on or govern the communities’ decisions
concerning the siting of wastewater treatment and conveyance facilities. By doing so, they would represent EPA impinging—without
clear statutory authority to do so—on land use questions typically reserved to states and local governments under the Constitution. 
See, e.g. , Rapanos v. United States , 547 U.S. 715, 738 (“Regulation of land use … is a quintessential state and local power.”) (Scalia,
J., concurring); Hess v. Port Auth. TransHudson Corp. , 513 U. S. 30, 44 (1994) (“[R]egulation of land use [is] a function traditionally
performed by local governments.”) . 
16 See American Canoe Ass’n v. Dist. of Columbia Water and Sewer Auth ., 306 F. Supp.2d 30, 46 (D.D.C. 2004) (citing NPDES
Permit Writers’ Manual for proposition that 40 C.F.R. § 122.41(e) “only requires permittees to maintain equipment in order to comply
with other express permit provisions”).

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C. The Major Events Planning Provisions’ Decades-Long Planning Horizons Are Inconsistent
with the CWA’s Five-Year Terms for NPDES Permits and the Certainty Provided by the
CWA’s Permit Shield. 
The Clean Water Act sets a five-year term for NPDES permits. 17 Although valid for only five years as a
matter of law, the Major Events Planning Provisions impose significant obligations that require MWRA and
Co-Permittees to consider and address hypothetical concerns that may or may not arise 20 to 30 years and 80 to
100 years after issuance of a final permit. EPA identifies no support in the CWA or its implementing
regulations for including in a five-year permit obligations concerning hypothetical conditions decades past the
permit’s expiration, and there is none. See Upper Blackstone Water Pollution Abatement Dist. , 690 F.3d at 22
(rejecting permittee’s argument for extension of an NPDES permit beyond five-year term because “neither the
CWA nor EPA regulations allow the [permittee’s] requested delay”). 
In addition to planning horizons that extend decades beyond the permit’s five-year term, the Major
Events Planning Provisions also purport to impose specific obligations more than five years from the permit’s
effective date. For example, the Draft Permit requires major storm and flood events plans to be updated “at
least every five (5) years from the effective date . . . and must take future conditions into consideration.” Draft
Permit, Part I.E.1.a, I.E.2.e(2). Because NPDES permits are limited to five-year terms, an obligation to update
these plans at least every five years will not arise during the term of the Draft Permit. 
The Draft Permit’s requirement for iterative planning, requiring updates on future conditions as data
sources are revised or generated, over a decades-long planning horizon is inconsistent with the CWA Section
402(k), 33 U.S.C. § 1342(k). The CWA’s “permit shield” provision protects permittees by deeming compliance
with an NPDES permit as compliance with the CWA. This protection affords a permittee the certainty to know
when the permit is issued what it must do to comply with its permit from the date of issuance through its five-
year term. This certainty “insulate[s] permit holders from changes in various regulations during the period of a
permit and to relieve permit holders of having to litigate the question of whether their permits are sufficiently
strict. In short, Section 402(k) serves the purpose of giving permits finality.” E.I. du Pont de Nemours & Co. v.
Train , 430 U.S. 112 (1977). 
The Major Events Planning Provisions requirements that a permittee modify plans pertaining to climate
change projections spanning 80 to 100 years “as data sources used for such evaluations are revised or
generated” contravenes and undermines the “finality” Congress intended Section 402(k) to afford. See Draft
Permit Part I.E.1.a, I.E.2.e(2). Consequently, a permittee will not know when it receives the permit what it will
need to do to comply through the duration of the permit’s term. As a practical matter, the modification
requirements threaten to place MWRA and its member communities in a perpetual, never-ending planning cycle
without any certainty about their compliance obligations. This is improper because it will deprive MWRA and
the communities of the certainty Congress intended to afford permittees when it enacted Section 402(k): the
ability to plan for the full extent of their CWA obligations when EPA issues their permits. 
17 33 U.S.C. §§ 1342(a)(3), (b)(1)(B); 40 C.F.R. § 122.46(a); Upper Blackstone Water Pollution Abatement Dist. v. EPA , 690 F.3d 9,
22 (1st Cir. 2012); Manasola-88 Inc. v. Thomas , 799 F.2d 687, 688 n.1 (11th Cir. 1986) (“NPDES permits are issued for a fixed term
not to exceed five years”); see also 314 CMR 3.11(8) (providing that discharge permits issued by Massachusetts “shall be effective for
a fixed term not to exceed five years” but allowing MassDEP to issue a permit “for a lesser duration”).

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D. The Major Events Planning Provisions Impose Significant Cost Burdens, Particularly for
Smaller Communities, Without the Benefit of a Cost-Benefit Analysis. 
The financial and resource burdens of developing, implementing, and updating storm and flood event
plans that the Major Events Planning Provisions require will be significant, especially for smaller communities
with limited financial and staffing resources. The investments to undertake this work, including the up-front
vulnerability and mitigation alternatives analysis and the significant implementation and ongoing re-evaluation
requirements, will likely require thousands of hours of personnel or consultant time. These costs could pale in
comparison to the potential capital costs that MWRA and the communities may incur in order to implement
mitigation measures that could even require relocating existing facilities or building new ones. The associated
financial burdens on MWRA and the communities are unknown but certain to be substantial. MWRA and the
communities will likely need to adjust their investments in critical infrastructure and other improvements to
meet these new requirements, and ratepayers will likely absorb any associated financial burdens in the form of
increased rates. 
These financial burdens are unknown because EPA and MassDEP are imposing them without having
assessed the costs and associated benefits of the Major Events Planning Provisions. Moreover, most, if not all,
utilities will likely need additional staffing resources to undertake these novel and substantial requirements. At
the very minimum, before issuing a final permit, EPA or MassDEP should provide permittees, their ratepayers,
and the public with a formal cost-benefit assessment that informs all interested parties of the cost burdens of
implementing these novel and significant planning and implementation requirements along with the perceived
benefits of the Major Events Planning Provisions so that they may understand how those perceived benefits
compare to benefits of other capital projects, including projects that aim to improve water quality. 
E. The Requirement to Develop and Begin Implementing Major Storm and Flood Plans
Within One Year Is Unrealistic. 
The Major Events Planning Provisions require MWRA and the communities to develop plans that
analyze individual facility and sewer system-related assets and assess vulnerabilities, conduct a systemic
vulnerability evaluation of each individual system and develop an alternatives analysis, and begin implementing
mitigation measures, all within twelve months of permit issuance. Permittees of any size will need more than
twelve months to plan and begin to implement these wide-ranging plans. If EPA insists on including major
storm and flood planning requirements, the agency should allow MWRA and the communities at least thirty-six
months to develop and begin implementing major storm and flood events plans for wastewater treatment
facilities and sewer systems. 
F. The Draft Permit Sets Forth Ambiguous Planning Standards for Major Storm and Flood
Events Plans. 
The Major Events Planning Provisions require MWRA and the communities to design and implement
measures to mitigate impacts of major storm and flood events, but it does not articulate a clear standard for
doing so. The Draft Permit requirements set forth both an obligation to develop measures to “minimize the
impact of major storm and flood events” and an obligation to select measures that are “the most effective.”
Draft Permit, Part I.E.1.a(1)iii, I.E.1.a(3), I.E.2.e(2)i.(c), I.E.2.e(2)iii. The Draft Permit defines “minimize” to
mean “to reduce and/or eliminate to the extent achievable the impacts to the facilities.” Part I.E.1.a(1)iii and
n.10, I.E.2.e(2)i.(c) and n.24. But the Draft Permit does not reconcile how the notion of achievability of

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measures in the definition of “minimize” plays a role in determining which measures are “the most effective”
for purposes of permit compliance. 
The Major Events Planning Provisions also call for a permittee to undertake a cost effectiveness analysis
for its mitigation measure alternatives, but they do not specify or provide any guidance as to what role costs—or
affordability—may play in selecting mitigation measures. See Draft Permit Part I.E.1.a(3), I.E.2.e(2)iii. For all
of the reasons set forth herein, EPA should jettison the Draft Permit’s novel Major Events Planning Provisions,
but if EPA nevertheless retains these provisions in the final permit, the agency should clarify these ambiguities
regarding the Major Events Planning Provisions’ planning standards. 
G. EPA Should Explore Whether Existing Efforts to Address Climate Change Are Adequate
to Address the Concerns EPA Seeks to Address Through the Major Events Planning
Provisions. 
Before requiring MWRA and the Co-Permittees to implement the onerous Major Events Planning
Provisions, EPA should assess whether and to what extent existing efforts to address climate change address or
could be adapted to address the concerns EPA seeks to address through those planning requirements. For
example, wastewater utilities in Massachusetts regularly seek funding from the Commonwealth’s Clean Water
State Revolving Fund (CWSRF) to obtain low interest loans for their asset management programs. The
CWSRF requires all applicants to comply with a number of planning and asset management requirements as a
prerequisite to obtaining funding under that program. EPA should assess whether and to what extent the
existing CWSRF planning and asset management requirements provide the type of information and analysis
EPA seeks through the Major Events Planning Provisions or could be adapted to provide that information. The
CWSRF is a better tool to address long-term planning obligations than an NDPES permit that is limited to
governing specific discharges over a five-year term. 
VI. Adaptation Plan Requirements in Recently-Issued NPDES Permits in EPA Region 1 Suffer From
Many of the Same Flaws as the Major Events Planning Provisions. 
After making the Draft Permit available for public comment, EPA issued to municipalities in
Massachusetts NPDES permits that require the development of “adaptation plans” that address climate change
concerns and made public new agency guidance setting forth requirements for those plans (“Adaptation Plan
Requirements”). The Adaptation Plan Requirements replace language in these permits that had been virtually
identical to the Major Events Planning Provisions in the Draft Permit but fail to correct the flaws outlined
above. 
For example, as discussed above, the Clean Water Act sets a five-year term for NPDES permits. 18 Like
the Major Events Planning Provisions, the Adaptation Plan Requirements also require MWRA and Co-
Permittees to consider and address hypothetical concerns that may or may not arise 20 to 30 years and 80 to 100
years after issuance of a final permit—decades after the permit will expire. EPA identifies no support in the
CWA or its implementing regulations for including in a five-year permit obligations concerning hypothetical
conditions decades past the permit’s expiration. See Upper Blackstone Water Pollution Abatement Dist. , 690
F.3d at 22 (rejecting permittee’s argument for extension of an NPDES permit beyond five-year term because
“neither the CWA nor EPA regulations allow the [permittee’s] requested delay”). 
18 See Section V.C., supra .

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The Adaptation Plan Requirements also seek to regulate capital planning and activities beyond the
permissible scope of any NPDES permit. As discussed at length above, the CWA allows NPDES permits to
impose only those conditions necessary to ensure compliance with the CWA’s requirements for discharge
quality. 19 EPA cannot use NPDES permits to regulate the facility itself, which is precisely what the Adaptation
Plan Requirements seek to do. 20 
At the heart of the Adaptation Plan Requirements are directives to assess and prepare a plan for
implementing “adaptive measures,” which EPA defines to include “building or modifying infrastructure,”
among other measures. See, e.g., City of Northampton, Massachusetts Authorization to Discharge under the
National Pollutant Discharge Elimination System - 2023 Final Permit (“Northampton 2023 Final Permit”) at 13,
n.9; see also EPA Region 1 Recommended Procedures and Resources for the Development of Adaptation Plans
for Wastewater Treatment Systems and/or Sewer Systems at 9 (Sept. 27, 2023). As with the Major Events
Planning Provisions, the Adaptation Plan Requirements’ directives to assess and potentially implement
significant capital projects 21 to address them bear no connection to the permissible scope of NPDES permit
terms: assuring compliance with applicable effluent limitations. These requirements impermissibly seek to
regulate MWRA’s and the communities’ facilities (and capital planning processes), not their discharges. They
also threaten to encroach upon land use decisions reserved to states and local governments. Because they
exceed EPA’s authority to issue NPDES permits, the Adaptation Plan Requirements should not be included in
the final permit. 
The Adaptation Plan Requirements’ failure to heed the distinction between permissibly regulating
discharges and impermissibly regulating facilities in an NPDES permit is highlighted by their definition of the
“impacts” of major storm and flood events that a permittee or co-permittee must assess: 
“Impacts” refers to a strong effect on an asset and/or asset-related operation that may include
destruction, damage or ineffective operation of the asset and/or asset operation. Impacts may be 
economic, environmental, or public health related . 
Northampton 2023 Final Permit at 12, n.9 (emphasis added). 
The Adaptation Plan Requirements direct permittees to assess the ability of their assets to function in the
event of these impacts “in terms of effluent flow . . . and discharges of pollutants.” Id . at 12. While 
environmental impacts of major storm and flood events on assets and operations might relate to how major
storm and flood events affect the quality of a facility’s discharge, economic and public health impacts of major
storm and flood events have no bearing on whether a facility’s discharges meet applicable effluent limitations.
In the absence of a connection between economic and public health impacts and the quality of effluent flow and 
19 See Section V.B., supra . 
20 See Waterkeeper All., Inc. v. U.S. E.P.A ., 399 F.3d 486, 505 (2d Cir. 2005) ((“[T]he Clean Water Act gives the EPA jurisdiction to
regulate and control only actual discharges—not potential discharges, and certainly not point sources themselves.”); Natural
Resources Defense Council v. EPA, 859 F.2d 156, 170 (D.C.Cir.1988) (“[T]he [Clean Water Act] does not empower the agency to
regulate point sources themselves; rather, EPA’s jurisdiction under the operative statute is limited to regulating the discharge of
pollutants.”); see also Iowa League of Cities v. EPA , 711 F.3d 844, 877 (8th Cir. 2013) (“effluent limitations are restricted to
regulations governing ‘discharges from point sources into navigable waters.’” (citing 33 U.S.C. § 1362(11))). 
21 See, e.g ., Northampton 2023 Final Permit at 14 (requiring revision of Adaptation Plan “if on- or off-site structures are added,
removed, or otherwise significantly changed in any way that will impact the vulnerability of the WWTS or sewer”).

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mwraadvisoryboard.com 
Matthew A. Romero
Executive Director 
discharges, there is no basis for EPA to require assessment of those impacts. At a minimum, the requirement to
consider economic and public health impacts of major storm and flood events on assets and asset-related
operations should be removed from the final permit. 
The three “Components” of the Adaptation Plan Requirements also raise the following concerns: 
Component 1 requires a permittee to perform “an identification of critical assets and related operations
… that are most vulnerable due to major storm and flood events . . . .” Northampton 2023 Final Permit at 12
(emphasis added). As written, this provision suggests the need for the permittee to make a subjective judgment
of which assets and asset-related operations are “most vulnerable” to major storm and flood events before
moving on to assess whether “these critical assets and related operations” can function properly. Component 1
would provide more clear direction to permittees if it required only an identification of critical assets and related
operations, without an initial assessment of their relative vulnerability. The second step would then consist of a
vulnerability assessment—an analysis of whether those assets and operations can function properly. 
Component 2 is ambiguous and confusing as drafted. Component 2 requires a permittee to undertake
“an assessment of adaptive measures … that minimize the impact of future conditions on the critical assets . . .
.” Northampton 2023 Final Permit at 13. The sentence that follows requires a permittee to “select the most
effective adaptation measures” for those critical assets “at the highest risk of not functioning under such
conditions.” Id . In addition to introducing a new, undefined term – “adaptation measures” (as opposed to
“adaptive measures,” which are defined) – this sentence also creates an internal inconsistency: Does this
component require a permittee to assess all critical assets or just those assets that are at the highest risk of not
functioning? To the extent the final permit includes the Adaptation Plan Requirements, this inconsistency
should be clarified and resolved. 
A permittee’s obligations under Component 3 are also ambiguous due to the inconsistencies in
Component 2. Component 3 requires a permittee to develop a schedule for implementation and maintenance of
adaptive measures “for each of the critical assets and related operations of the WWTS and sewer system . . . .”
Northampton 2023 Final Permit at 13. This suggests that Component 3 requires a permittee to provide this
schedule for all of its critical assets, but a reasonable interpretation of Component 2 suggests that a permittee
need only identify adaptive measures for critical assets that are “at the highest risk of not functioning.” Id .
EPA will need to resolve this ambiguity to the extent the final permit contains the Adaptation Plan
Requirements. 
In more recent permits, Component 3 also requires a permittee to include in its implementation and
maintenance schedule “an evaluation of how each adaptive measure taken (or planned) will be funded.”
Hoosac Water Quality District Authorization to Discharge under the National Pollutant Discharge Elimination
System - 2023 Final Permit (“Hoosac 2023 Final Permit”) at 12. This addition is problematic because it
requires a permittee to undertake a funding evaluation for measures that may not need to be taken for thirty or
more years, if ever. Assessing funding for improvements that may not be implemented for decades would only
be speculative and require municipalities to expend scarce ratepayer resources to conduct an evaluation that will
be of little value to the permittee, regulators, or the public. 
VII. Additional Issues in the Draft Permit that EPA Must Address

Advocacy & Accountability 
2 Griffin Way, Suite A, Chelsea, MA 02150 mwra.ab@mwraadvisoryboard.com 
mwraadvisoryboard.com 
Matthew A. Romero
Executive Director 
In addition to the foregoing, the Advisory Board has identified the following errors in the Draft Permit
that must be corrected: 
Part I.E.2.c.(4) : This provision, which requires MWRA to submit an annual summary report
concerning actions taken to reduce infiltration and inflow, appears to be incomplete. In its current form, this
permit term provides summary and background information but does not appear to be drafted as formal permit
language. EPA must revise this language and reissue the Draft Permit for public comment so that the Advisory
Board and the communities can meaningfully comment on them. 
Part I.E.2.c.(4) : This provision, which “requires the Co-permittees to prepare and submit I/I Reduction
Plans,” appears to be incomplete. In its current form, this permit term provides summary and background
information but does not specify the substantive content of the required I/I Reduction Plans. EPA must specify
what these plans include and re-issue the Draft Permit for public comment so that the Advisory Board and the
communities can meaningfully comment on them. 
Part I.E.2.(e)(3)(ii) : This provision currently reads, “A preventive maintenance and monitoring
program for the collection system; including resiliency evaluation and planning that the Permittee, Co-
Responsible Co-permittees and Co-permittees owns and operates.” In its current form, this language is hard to
follow and likely reflects drafting errors. The Board proposes that this provision be revised to read, “A
preventive maintenance and monitoring program for the collection system that Permittee, CSO-responsible Co-
Permittees, and Co-Permittees each own and operate.” 
Part I.E.2.(e)(3)(iii) : Although this provision applies to CSO-responsible Co-Permittees, it introduces
confusion by referring to “the sanitary sewer collection system.” To eliminate this confusion, the Advisory
Board requests that EPA delete the word “sanitary.” 
Part I.E.2.(e)(3)(iv) : This provision currently reads, “Description of funding, the source(s) of funding
and provisions for funding sufficient for implementing the plan that the Permittee, CSO-responsible Co-
permittees, and Co-permittees owns and operates plan.” In its current form, this language is hard to follow, a
likely product of a drafting mistake. The Board proposes that this provision instead read, “Description of
funding, the source(s) of funding and provisions for funding sufficient for implementing the Plan that the
Permittee, CSO-Responsible Co-permittee, or Co-permittee has developed.” 
VIII. Conclusion 
The Advisory Board appreciates the opportunity to comment on the Draft Permit and State Permit.
Please feel free to contact the Board’s Executive Director, Matthew Romero
(Matthew.Romero@mwraadvisoryboard.com; 617-788-2054) if you have any questions or would like to
arrange a meeting to discuss the resolution of the issues raised above. 
Sincerely, 
Matthew A. Romero 
Executive Director | MWRA Advisory Board

Attachment A

UNITED STATES ENVIRONMENTAL PROTECTION AGENCY 
Region 1
5 Post Office Square, Suite 100
Boston, MA 02109-3912 
VIA E MAIL - READ RECEIPT REQUESTED 
March 8, 2023 
Re: Waiver of Permit Application and Signatory Requirements for Municipal Satellite Sewage
Collection System – co-permittees to the MWRA Deer Island Treatment Plant, NPDES No.
MA0103284 
Dear MWRA Deer Island Treatment Plant Satellite Collection System Member Community: 
EPA Region 1 is currently developing a draft National Pollutant Discharge Elimination System (NPDES)
discharge permit and an accompanying fact sheet that summarizes the significant facts, legal and policy
questions considered in preparing the draft permit for the Massachusetts Water Resources Authority Deer
Island Treatment Plant (MWRA DITP) including the collection systems from all member communities.
The purpose of this letter is to inform you of our plans for incorporating communities with satellite
collection systems that discharge into the MWRA DITP as co-permittees in the permit and any permit
application requirements. Please be advised that your municipality will be included as a co-permittee in
the forthcoming Draft NPDES discharge permit issued to the MWRA for the DITP. 
The satellite collection system member communities of the MWRA DITP listed in Attachment A will all
be included as co-permittees in the draft discharge permit issued for the DITP. Under NPDES regulations,
all Publicly Owned Treatment Works (POTWs) must submit permit application information set forth in
40 CFR § 122.21(j) unless otherwise indicated. Where Region 1 of the Environmental Protection Agency
(EPA) has “access to substantially identical information,” or such information is “not of material concern
for a specific permit,” the Regional Administrator may waive permit application requirements for existing
POTWs. Id. Pursuant to my authority under this regulation, I am waiving NPDES permit application and
signatory requirements applicable to certain operators, including your system, of the municipal satellite
collection systems that contribute to the MWRA DITP. 
EPA regulations do not specifically address how NPDES permit coverage is to be obtained by satellite
collection system components of POTWs. Ordinarily the treatment plant operator applies for the POTW’s
NPDES permit, and discharges from the POTW, including those from the collection systems operated by
others, are covered by the permit issued to the treatment plant. Satellite collection system operators have
generally not submitted separate permit applications for coverage under the POTW permit, because the
treatment plant operator generally submits the information necessary for the permit writer to write limits
and conditions in the permit applicable to all components of the POTW on the basis of the treatment
plant’s application. Receiving a single application from the operator of a portion of the discharging
POTW is one reasonable way to structure the permit application process, particularly in the case of a
regionally integrated treatment works where there is a centralized administrative entity responsible for
operating the POTW Treatment Plant and coordinating wastewater flows from the multiple satellite
collection system operators that all contribute to the final effluent discharge. 
Although EPA has the authority to require operators of the municipal satellite collection systems to
submit individual permit applications, in this case I find that requiring a single permit application
executed by the regional POTW owner/operator will be sufficient, as I have been provided, or have access
to, “substantially identical information” to what would have been provided to EPA by the collection
system operator, or that the detailed information requirements of Form 2A are not otherwise material to

EPA’s drafting of co-permittee requirements. Requiring a single application will also be less duplicative
and less burdensome than requiring separate applications from each municipal satellite collection system
owner/operator. Municipal satellite collection system owners/operators should consult with the regional
POTW operators to ensure that any information provided to EPA about their respective entities is
accurate and complete. If EPA requires additional information, it may use its information collection
authority under CWA § 308. 33 U.S.C. § 1318. 
As a general matter, EPA does not foresee the need to require individual permit applications from each
municipal satellite collection system operator and anticipates that information in the POTW operator’s
permit application and other information in the administrative record will be sufficient to establish permit
limits and conditions for the entire treatment works. In the future permitting cycles, EPA will indicate
whether it will require additional material from those entities operating the outlying portions of the
treatment works to render the permit application “complete” under 40 CFR § 124.3(c) after receiving and
reviewing the re-application for the permit from the MWRA DITP. 
This notice reflects my determination based on the specific facts and circumstances in this case. It is not
intended to bind the agency in future determinations where a separate permit for municipal satellites
would not be duplicative or immaterial. 
Prior to issuing the draft permit and fact sheet for public notice, EPA Region 1 will hold a virtual
informational session for MWRA and the co-permittees on March 28, 2023 from 1:00 pm to 2:00 pm
( Click here to join the meeting ). EPA will explain the draft permit’s co-permittee requirements at this 
meeting and will answer questions pertaining to EPA Region 1’s co-permitting strategy. 
The co-permittees and MWRA will each receive a copy of the draft permit and the fact sheet when EPA
publicly notices them. The public will then have at least 30 days to submit comments on the draft permit
to EPA. Consistent with 40 CFR § 124.10, EPA’s public notice will detail how the public may comment
on the draft permit. 
If you have any questions or would like to discuss this decision, do not hesitate to contact Michele Barden
of my staff at (617) 918-1539 or barden.michele@epa.gov . 
Sincerely, 
David W. Cash 
Regional Administrator 
Office of the Regional Administrator 
cc: Claire Golden, MassDEP 
Frederick Laskey, MWRA

Attachment A 
Co-permittees to NPDES Permit No. MA0103284 
MWRA Deer Island Treatment Plant 
Town of Arlington 
Department of Public Works 
51 Grove Street 
Arlington, MA 02476 
Town of Ashland 
Department of Public Works 
20 Ponderosa Road 
Ashland, MA 01721 
Town of Bedford 
Department of Public Works 
314 Great Road 
Bedford, MA 01730 
Town of Belmont 
Department of Public Works 
19 Moore Street 
Belmont, MA 02478 
Town of Braintree 
Department of Public Works 
P.O. Box 850903 
Braintree, MA 02185-0903 
Town of Brookline 
Town Engineer 
333 Washington Street 
Brookline, MA 02445 
Town of Burlington 
Town Engineer 
29 Center Street 
Burlington, MA 01803 
Town of Canton 
Department of Public Works 
801 Washington Street 
Canton, MA 02021 
Town of Dedham 
Department of Public Works 
55 River Street 
Dedham, MA 02026 
City of Everett 
Department of Public Works 
19 Norman Street 
Everett, MA 02149 
City of Framingham 
Department of Public Works 
100 Western Avenue 
Framingham, MA 01701 
Town of Hingham 
Department of Public Works 
210 Central Street 
Hingham, MA 02043 
Town of Holbrook 
Department of Public Works 
50 N. Franklin Street 
Holbrook, MA 02343 
Town of Lexington 
Department of Public Works 
201 Bedford Street 
Lexington, MA 02420 
City of Malden 
Department of Public Works 
200 Pleasant Street 
Malden, MA 02148 
City of Medford 
Town Engineer 
85 George P. Hassett Drive 
Medford, MA 02155 
City of Melrose 
Department of PublicWorks 
72 Tremont St. 
Melrose, MA 02176 
Town of Milton 
Department of Public Works 
629 Randolph Avenue 
Milton, MA 02186 
Town of Natick 
Department of Public Works 
75 West Street 
Natick, MA 01760 
Town of Needham 
Department of Public Works 
470 Dedham Avenue 
Needham, MA 02492 
City of Newton 
Department of Public Works 
1000 Commonwealth Avenue 
Newton, MA 02459 
Town of Norwood 
Department of Public Works 
566 Washington Street 
Norwood, MA 02062 
City of Quincy 
Department of Public Works 
55 Sea Street 
Quincy, MA 02169 
Town of Randolph 
Department of PublicWorks 
41 South Main Street 
Randolph, MA 02368

Town of Reading 
Department of Public Works 
16 Lowell Street 
Reading, MA 01867 
City of Revere 
Department of PublicWorks 
321 Rear Charger Street 
Revere, MA 02151 
Town of Stoneham 
Public Works Department 
16 Pine Street 
Stoneham, MA 02180 
Town of Stoughton 
Department of PublicWorks 
950 Central Street 
Stoughton, MA 02072 
Town of Wakefield 
Director of Public Works 
1 Lafayette Street 
Wakefield, MA 01880 
Town of Walpole 
Department of PublicWorks 
135 School Street 
Walpole, MA 02081 
City of Waltham 
Department of PublicWorks 
165 Lexington Street 
Waltham, MA 02452 
Town of Watertown 
Department of PublicWorks 
124 Orchard Street 
Watertown, MA 02472 
Town of Wellesley 
Department of PublicWorks 
455 Worcester Street 
Wellesley, MA 02481 
Town of Westwood 
Department of PublicWorks 
50 Carby Street 
Westwood, MA 02090 
Town of Weymouth 
Department of PublicWorks 
120 Winter Street 
Weymouth, MA 02188 
Town of Wilmington 
Department of Public Works 
121 Glen Road 
Wilmington, MA 01887 
Town of Winchester 
Department of PublicWorks 
15 Lake Street 
Winchester, MA 01890 
Town of Winthrop 
Department of Public Works 
100 Kennedy Drive 
Winthrop, MA 02152 
City of Woburn 
Public Works Sewer Division 
50 North Warren Street 
Woburn, MA 01801 
NOTE: The Cities of Boston, Cambridge, Chelsea and Somerville have received separate letters as current
permittees under NPDES Permit Nos. MA0101192, MA0101974, MA0101877 and MA0101982, respectively.

Attachment B

Attachment B
MWRA Advisory Board Comments 
NPDES Permit No. MA0103284 2023 Draft Permit 
AUTHORIZATION TO DISCHARGE UNDER THE
NATIONAL POLLUTANT DISCHARGE ELIMINATION SYSTEM 
In compliance with the provisions of the Federal Clean Water Act as amended, 33 U.S.C. §§ 1251
et seq. (the “CWA”), 
Massachusetts Water Resource Authority (MWRA) 
is authorized to discharge from the facility located at 
MWRA Deer Island Treatment Plant (DITP) 
190 Tafts Avenue 
Winthrop, MA 02152 
to the receiving water named 
Receiving Water Segment Outfall 
Massachusetts Bay Undefined, 314 CMR 4.06. Table 23 T01 
and 
Four (4) Combined Sewer Overflow (CSO) Treatment Facilities with 5 outfalls 
to the receiving waters named 
Receiving Water Segment CSO Treatment Facility Name Outfalls 
Boston Inner Harbor MA70-02 Prison Point MWR203 
Boston Inner Harbor MA70-02 Union Park MWR215 
Mystic River MA71-03 Somerville Marginal MWR205 
Upper Mystic River MA71-02 Somerville Marginal MWR205A 
Charles River MA72-38 Cottage Farm MWR201 
and 
Six (6) additional Combined Sewer Overflow (CSO) Outfalls (See Attachment A) 
in accordance with effluent limitations, monitoring requirements and other conditions set forth herein. 
NOTE: The former near shore DITP outfalls: 001, 002, 003, 004 and 005, are not authorized under the
Permit. The Permit no longer requires the Permittee to maintain these nearshore Deer Island outfalls
as a contingency option. 
The Massachusetts municipalities listed below are identified as CSO-responsible Co-permittees
responsible forfor ensuring that their own discharges, infrastructure, activities, and required
reporting with respect to the sewer system that each CSO-responsible Co-Permittee owns and
operates comply with Part B., Combined Sewer Overflows, Part C., Unauthorized Discharges, Part
D., Notice of Elimination, Part E., Operation and Maintenance, which includes conditions regarding

Attachment B
MWRA Advisory Board Comments 
the operation and maintenance of the collection systems owned and operated by the municipalities;
Part F., Alternate Power Source, and Part J., Reporting Requirements. The list of CSO outfalls, the
CSO-responsible party, receiving waters and locations are found in Attachment A . 
MAC053284 MAC093284 MAC113284 MAC293284 
City of Boston
Boston Water and
Sewer Commission
980 Harrison Avenue
Boston, MA 02119 
City of Cambridge
Department of Public
Works
147 Hampshire Street
Cambridge, MA
02139 
City of Chelsea
Department of Public
Works
380 Beacham Street
Chelsea, MA 02150 
City of Somerville
Department of Public
Works
1 Franey Road
Somerville, MA
02144 
The Massachusetts municipalities in Attachment B are identified as Co-permittees related
toresponsible for ensuring that their own discharges, infrastructure, activities, and required reporting
with respect to the sewer system that each Co-permittee operation and maintenance of the sewer
systems in complianceowns and operates complies with the Standard Conditions of Part II and the
terms and conditions of Part C., Unauthorized Discharges, Part E., Operation and Maintenance,
which includes conditions regarding the operation and maintenance of the collection systems owned
and operated by the municipality, Part F., Alternate Power Source, and Part J. Reporting
Requirements. 
The Permittee, CSO-responsible Co-permittees and each Co-permittee are severally liable for their own
activities and discharges under the Standard Conditions of Part II, Parts B, C, E, F, and required
reporting under Part J with respect to the portions of the sewer system that they each owns andor
operates. They are not liable for violations of the Standard Conditions of Part II, Parts B, C, E, F and
Part J committed by others relative to the portions of the collection system owned and operated by
others. Nor are they responsibleThey are also not liable for any other Permittee’s, CSO-responsible Co-
permittee’s or Co-permittee’s failure to provide for any reporting that is required of other Permittees
under the Standard Conditions of Part II, Part C, Part E, Part F, and Part J. Moreover, CSO-responsible
Co-permittees and Co-permittees are not liable for any violations of Parts A, D, G, H, I, J or K
committed by the Permittee. The responsible municipal departments are found in Attachment B . 
This Permit shall become effective on the first day of the calendar month immediately following 60
days after signature. 1 
This Permit expires at midnight, five years from the last day of the month preceding the effective date. 
This Permit supersedes the NPDES Permit No. MA0103284 issued on May 20, 1999, and
subsequently modified on July 10, 2000; NPDES Permit No. MA0101192 issued on March 28, 2003
and subsequently modified on April 10, 2007; NPDES Permit No. MA0101974 issued on September
30, 2009; NPDES Permit No. MA0101877 issued on November 26, 2013; and NPDES Permit No.
MA0101982 issued on June 11, 2012. 
This Permit consists of Part I including the cover page(s), Attachment A (Authorized CSO Outfalls
and Responsible Parties), Attachment B (MWRA Member Communities named as Co-permittees),

Attachment B
MWRA Advisory Board Comments 
Attachment C (Marine Acute Toxicity Test Procedure and Protocol, July 2012), Attachment D 
(Marine Chronic Toxicity Test Procedure and Protocol, November 2013), Attachment E (Freshwater
Acute Toxicity Test Procedure and Protocol, February 2011), Attachment F (Reassessment of
Technically Based Industrial Discharge Limits), Attachment G (Industrial Pretreatment Annual
Report), Attachment H (PFAS Analyte List), Attachment I (Authorized Typical Year CSO 
1 Pursuant to 40 Code of Federal Regulations (CFR) § 124.15(b)(3), if no comments requesting a change to the Draft
Permit are received, the permit will become effective upon the date of signature. Procedures for appealing EPA’s Final
Permit decision may be found at 40 CFR § 124.19.

Attachment B
MWRA Advisory Board Comments 
NPDES Permit No. MA0103284 2023 Draft Permit 
Page 3 of 68 
Discharge Activations and Volumes), Attachment J (Charles River Basin CSO Variance
Determination), Attachment K (Alewife and Upper Mystic River Basin CSO Variance
Determination) and Part II (NPDES Part II Standard Conditions, April 2018). 
Signed this day of 
Ken Moraff, Director 
Water Division 
Environmental Protection Agency

Attachment B
MWRA Advisory Board Comments 
Region 1 
Boston, MA

Attachment B
MWRA Advisory Board Comments 
NPDES Permit No. MA0103284 2023 Draft Permit 
Page 4 of 68 
PART I 
A. EFFLUENT LIMITATIONS AND MONITORING REQUIREMENTS FOR OUTFALL T01 
1. During the period beginning on the effective date and lasting through the expiration date, the Permittee, MWRA, is authorized to
discharge treated effluent through Outfall Serial Number T01 to Massachusetts Bay. The discharge shall be limited and monitored
as specified below; the receiving water and the influent shall be monitored as specified below. 
Effluent Characteristic 
Effluent Limitation Monitoring Requirements 1,2,3 
Average Monthly Average
Weekly Maximum Daily Measurement
Frequency Sample
Type 4 
Rolling Average Effluent Flow 5,6 361 MGD 5 --- --- Continuous Recorder 
Effluent Flow 5,6 Report MGD --- Report MGD Continuous Recorder 
CBOD 5 25 mg/L 40 mg/L Report mg/L 1/Day Composite 
CBOD 5 Removal 7 2 85 % --- --- 1/Month Calculation 
TSS 30 mg/L 45 mg/L Report mg/L 1/Day Composite 
TSS Removal 7 2 85 % --- --- 1/Month Calculation 
pH Range 8 6.0 - 8.5 S.U. 1/Day Grab 
Total Residual Chlorine 9,10 456 μg/L --- 631 μg/L 3/Day Grab 
Fecal Coliform 9,10,11,12 980 organisms
/100 mL --- 1,960 
organisms/100 mL 3/Day Grab 
Enterococci 9,10,12 
(April 1 through October 31) 2,450 cfu/100 mL --- 9,100 cfu/100 mL 3/Day Grab 
Oil and Grease 13 Non-detect mg/L --- --- 1/Day Grab 
Ammonia Nitrogen 14 Report mg/L --- Report mg/L 1/Month Composite 
Total Kjeldahl Nitrogen 14 
(April 1 through October 31)
(November 1 through March 31) 
Report mg/L --- Report mg/L 1/Week
1/Month 
Composite 
Nitrate + Nitrite 14 
(April 1 through October 31) 
(November 1 through March 31) 
Report mg/L --- Report mg/L 1/Week
1/Month 
Composite

Attachment B
MWRA Advisory Board Comments 
Total Nitrogen 14 
(April 1 through October 31) Report mg/L --- Report mg/L 1/Week Calculation

Attachment B
MWRA Advisory Board Comments 
NPDES Permit No. MA0103284 2023 Draft Permit 
Page 5 of 68 
Effluent Characteristic 
Effluent Limitation Monitoring Requirements 1,2,3 
Average Monthly Average
Weekly Maximum Daily Measurement
Frequency 
Sample
Type 4 
(November 1 through March 31) 1/Month 
PFAS Analytes 15 --- --- Report ng/L 1/Quarter Grab 
Adsorbable Organic Fluorine 16 --- --- Report ng/L 1/Quarter Grab 
Effluent Characteristic 
Effluent Limitation Monitoring Requirements 1,2,3 
Average Monthly Average
Weekly Maximum Daily Measurement
Frequency 
Sample
Type 4 
Whole Effluent Toxicity (WET) Testing 17,18 
LC 50 --- --- ? 100 % 1/Quarter Composite 
C-NOEC --- --- ? 1.5 % 1/Quarter Composite 
Salinity --- --- Report ppt 1/Quarter Composite 
Ammonia Nitrogen --- --- Report mg/L 1/Quarter Composite 
Total Cadmium --- --- Report mg/L 1/Quarter Composite 
Total Copper --- --- Report mg/L 1/Quarter Composite 
Total Nickel --- --- Report mg/L 1/Quarter Composite 
Total Lead --- --- Report mg/L 1/Quarter Composite

Attachment B
MWRA Advisory Board Comments 
Total Zinc --- --- Report mg/L 1/Quarter Composite 
Total Organic Carbon --- --- Report mg/L 1/Quarter Composite

Attachment B
MWRA Advisory Board Comments 
NPDES Permit No. MA0103284 2023 Draft Permit 
Page 6 of 68 
Ambient Characteristic 19 
Reporting Requirements Monitoring Requirements 1,2,3 
Average
Monthly 
Average
Weekly Maximum Daily Measurement
Frequency Sample Type 4 
Fecal Coliform 11,12 – Surface --- --- Report 
organisms/100 mL 1/Month Grab 
Fecal Coliform 11,12 – Below pycnocline --- --- Report 
organisms/100 mL 1/Month Grab 
Enterococci 11,12 - Surface
(April 1 through October 31) --- --- Report cfu/100
mL 1/Month Grab 
Enterococci 11,12 - Below pycnocline
(April 1 through October 31) --- --- Report cfu/100
mL 1/Month Grab 
Salinity --- --- Report ppt 1/Quarter Grab 
Ammonia Nitrogen --- --- Report mg/L 1/Quarter Grab 
Total Cadmium --- --- Report mg/L 1/Quarter Grab 
Total Copper --- --- Report mg/L 1/Quarter Grab 
Total Nickel --- --- Report mg/L 1/Quarter Grab 
Total Lead --- --- Report mg/L 1/Quarter Grab 
Total Zinc --- --- Report mg/L 1/Quarter Grab 
Total Organic Carbon --- --- Report mg/L 1/Quarter Grab 
Dissolved Organic Carbon 20 --- --- Report mg/L 1/Quarter Grab 
pH 21 --- --- Report S.U. 1/Quarter Grab

Attachment B
MWRA Advisory Board Comments 
Temperature 21 --- --- Report °C 1/Quarter Grab

Attachment B
MWRA Advisory Board Comments 
NPDES Permit No. MA0103284 2023 Draft Permit 
Page 7 of 68 
Influent Characteristic 
Reporting Requirements Monitoring Requirements 1,2,3 
Average
Monthly 
Average
Weekly 
Maximum
Daily 
Measurement
Frequency Sample Type 4 
CBOD 5 7 Report mg/L --- --- 2/Month Composite 
TSS 7 Report mg/L --- --- 2/Month Composite 
PFAS Analytes 15 --- --- Report ng/L 1/Quarter Grab 
Adsorbable Organic Fluorine 16 --- --- Report ng/L 1/Quarter Grab 
Reporting Requirements Monitoring Requirements 1,2,3

Attachment B
MWRA Advisory Board Comments 
Sludge Characteristic 
Average
Monthly 
Average
Weekly 
Maximum
Daily 
Measurement
Frequency Sample Type 4 
PFAS Analytes 15 --- --- Report ng/g 1/Quarter Grab 21

Attachment B
MWRA Advisory Board Comments 
NPDES Permit No. MA0103284 2023 Draft Permit 
Page 8 of 68 
Footnotes: 
1. All samples shall be collected in a manner to yield representative data. A routine
sampling program shall be developed in which samples are taken at the same location,
same time and same days of the week each month. Occasional deviations from the
routine sampling program are allowed, but the reason for the deviation shall be
documented as an electronic attachment to the applicable discharge monitoring report.
The Permittee shall report the results to the Environmental Protection Agency Region 1
(EPA) and the MassDEP of any additional testing above that required herein, if testing
is in accordance with 40 CFR Part 136. 
2. In accordance with 40 CFR § 122.44(i)(1)(iv), the Permittee shall monitor according to
sufficiently sensitive test procedures (i.e., methods) approved under 40 CFR Part 136 or
required under 40 CFR chapter I, subchapter N or O, for the analysis of pollutants or
pollutant parameters (except WET). A method is “sufficiently sensitive” when: 1) The
method minimum level (ML) is at or below the level of the effluent limitation established
in the permit for the measured pollutant or pollutant parameter; or 2) The method has the
lowest ML of the analytical methods approved under 40 CFR Part 136 or required under
40 CFR chapter I, subchapter N or O for the measured pollutant or pollutant parameter.
The term “minimum level” refers either to the sample concentration equivalent to the
lowest calibration point in a method or a multiple of the method detection limit (MDL),
whichever is higher. Minimum levels may be obtained in the following ways: they may
be published in a method; they may be based on the lowest acceptable calibration point
used by a laboratory; or they may be calculated by multiplying the MDL in a method, or
the MDL determined by a laboratory, by a factor. 
3. When a parameter is not detected above the ML, the Permittee must report the data
qualifier signifying less than the ML for that parameter (e.g., < 50 ji g/L, if the ML for a
parameter is 50 ji g/L). For reporting an average based on a mix of values detected and not
detected, assign a value of “0” to all non-detects for that reporting period and report the
average of all the results. 
4. A “grab” sample is an individual sample collected in a period of less than 15 minutes. A
“composite” sample is a composite of at least twenty-four (24) grab samples taken during
one consecutive 24-hour period, either collected at equal intervals and combined
proportional to flow or continuously collected proportional to flow. 
5. The 365-calendar day running average dry day flow shall not exceed 361 MGD. For this
purpose, a “dry day” is defined as a day with 0.09 inches of precipitation or less and no
snow melt, provided that the precipitation on the previous day is less than 0.3 inch, and the
precipitation on the day two days prior to the day in question is less than 1.0 inch, and the

Attachment B
MWRA Advisory Board Comments 
precipitation on the day three days prior to the day in question is less than 2.0 inches. A
day with snow melt is defined as a day when there is snow on the ground and the air

Attachment B
MWRA Advisory Board Comments 
NPDES Permit No. MA0103284 2023 Draft Permit 
Page 9 of 68 
temperature rises above 32 degrees Fahrenheit. Flow from the CSO storage facilities is
not included in the dry day calculation. 
Compliance with this flow limit will be determined each month by calculating the 
average dry day flow over the previous 365 calendar days. The once-a-month calculation
shall include all dry day flow that occurred during the reporting month [Total dry day
flow/total number of dry days]. 
6. Within 24 hours after the commencement of any diversions of wastewater around
secondary treatment facilities at the DITP, the Permittee shall notify EPA by telephone or
email of the commencement of the diversion of wastewater around secondary treatment
facilities. 
Within 5 days of the commencement of any diversion of wastewater around secondary
treatment facilities at DITP, the Permittee shall provide EPA and MassDEP a written
submission containing a description of the diversion, its cause and the period of the
diversion, including its exact dates and times. If the diversion has not stopped by when
the written submission is due, the written submission shall also include a statement as to
the anticipated time it is expected to continue, and any steps taken or planned to reduce or
eliminate the diversion. 
A bypass of secondary treatment is subject to the requirements of Part II.B.4.and Part
II.D.1.e. of this Permit. 
Flows shall be measured using a meter. The requirement to measure flows which bypass
secondary treatment using a meter shall take effect 6 months following the effective date
of the Permit. 
The Permittee shall not add septage to the waste stream at the treatment plant during
activation of the secondary treatment bypass. 
7. For the purposes of calculating CBOD 5 and TSS percent removal, the Permittee shall
only use the data from dry days. The influent samples shall be taken on dry days. 
A “dry day” is defined as a day with 0.09 inches of precipitation or less and no snow
melt, provided that the precipitation on the previous day is less than 0.3 inch, and the
precipitation on the day two days prior to the day in question is less than 1.0 inch, and the
precipitation on the day three days prior to the day in question is less than 2.0 inches. A
day with snow melt is defined as a day when there is snow on the ground and the air

Attachment B
MWRA Advisory Board Comments 
temperature rises above 32 degrees Fahrenheit. Flow from the CSO storage facilities is
not included in the dry day calculation.

Attachment B
MWRA Advisory Board Comments 
NPDES Permit No. MA0103284 2023 Draft Permit 
Page 10 of 68 
8. The pH shall be within the specified range at all times. The minimum and maximum pH
sample measurement values for the month shall be reported in standard units (S.U.). See
Section I.K.2. of this Permit for additional State requirements. 
9. The Permittee shall minimize the use of chlorine while maintaining adequate bacterial
control. Monitoring for total residual chlorine (TRC) is only required for discharges
which have been previously chlorinated, or which contain residual chlorine. 
The Permittee may simulate the chlorine contact time in the outfall pipe prior to
dechlorination by holding the sample in conditions similar to those that would be present
at the outfall pipe, T01, before measuring the TRC, Enterococcus and fecal coliform. 
The holding time shall be calculated based on the effluent flow at the time of sample
collection and time for disinfection. The holding time and supporting calculation shall be
submitted as an attachment to the monthly DMRs. The Permittee may either use process
software or manual means for calculation. 
Chlorination and dechlorination systems shall include an alarm system for indicating
system interruptions or malfunctions. Any interruption or malfunction of the chlorine
dosing system that may have resulted in levels of chlorine that were inadequate for
achieving effective disinfection, or interruptions or malfunctions of the dechlorination
system that may have resulted in excessive levels of chlorine in the final effluent shall be
reported with the monthly DMRs. The report shall include the date and time of the
interruption or malfunction, the nature of the problem, and the estimated amount of time
that the reduced levels of chlorine or dechlorination chemicals occurred. 
10. The monthly average limits for fecal coliform and Enterococcus are expressed as
a geometric mean. Fecal coliform and Enterococcus monitoring shall be
conducted concurrently with TRC monitoring. 
11. In addition to the effluent limits for bacteria, MWRA is required to update the existing
Memorandum of Understanding (MOU) between the MWRA, the Massachusetts 
Division of Marine Fisheries (MA Marine Fisheries) and the US Food and Drug
Administration (FDA) and implementation of the MOU and the attached monitoring plan
is required by the Draft Permit (See Footnote 11). The updated Plan shall follow the same
procedures and locations as documented in Attachments A & B of the MOU with the
addition of station N21, located over the mid-point of the diffuser. The updated MOU and
monitoring plan shall be submitted to the MA Marine Fisheries and the FDA for review
and signature. The signed MOU and attached monitoring plan shall be submitted to EPA
and MassDEP within 12 months of the effective permit. Enterococcus should also

Attachment B
MWRA Advisory Board Comments 
continue to be monitored seasonally (April 1 through October 31) along with fecal
coliform to ensure that MA WQS for bacteria are met.

Attachment B
MWRA Advisory Board Comments 
NPDES Permit No. MA0103284 2023 Draft Permit 
Page 11 of 68 
The Permittee shall report the results of the monthly ambient fecal coliform and 
Enterococcus monitoring on their monthly DMRs for station N21. If the Bay is
stratified at the time of sampling, the Permittee shall sample at the surface and below
the pycnocline. If the Bay is not stratified, the Permittee should enter a NODI code = 9
for the below pycnocline DMR line. The ambient fecal coliform bacteria and 
Enterococcus monitoring results at the other sampling locations shall be submitted as an
attachment to the monthly DMR. If an adverse-conditions monitoring event occurs,
MWRA shall provide a letter summarizing the event and the sampling data collected as
an attachment to the monthly DMR. Any updates or changes in the Ambient Bacteria
Monitoring Plan shall be submitted to MA Marine Fisheries and the FDA for review.
The signed MOU and plan shall be submitted to EPA. 
12. If the MA DMF and/or the FDA determines in writing that the fecal coliform bacteria
limit is inadequate to ensure protection of shellfish resources, and EPA concurs in
writing, then the Permittee shall meet the following limits: 
Effluent Limitation Monitoring Requirements 
Effluent 
Characteristic 
Average
monthly 
Average
Weekly 
Maximum
Daily 
Measurement
Frequency 
Sample
Type 
Fecal Coliform
Bacteria, 
(organisms/100 mL) 
14 --- 28 3/Day Grab 
13. Oil and grease shall be tested using EPA Method 1664-n-Hexane Extractable Material
(HEM; Oil and Grease) and Silica Gel Treated n-Hexane Extractable Material (SGT-
HEM; Non-polar Material) by Extraction and Gravimetry Revision A or Method 1664
Revision B. 
The Permittee shall have no detectable discharge of oil and grease. Compliance shall be
measured at the minimum level (ML) of detection for the EPA approved test methods.
The oil and grease ML is 5 mg/L using EPA Method 1664 (Revisions A and B), where
the ML is the lowest point on the curve used to calibrate the test equipment for the
pollutant of concern. If EPA approves a method under 40 CFR Part 136 for either, oil
and grease that has a ML lower than 5 mg/L, the Permittee shall be required to use the
improved method. 
14. Ammonia Nitrogen, Total Kjeldahl nitrogen and nitrate + nitrite samples shall be
collected concurrently. The results of these analyses shall be used to calculate both
the concentration and mass loadings of total nitrogen, as follows. 
Total Nitrogen (mg/L) = Total Kjeldahl Nitrogen (mg/L) + Nitrate + Nitrite (mg/L)

Attachment B
MWRA Advisory Board Comments 
Total Nitrogen (lb/day) = [(average monthly Total Nitrogen (mg/L) * total monthly
effluent flow (Millions of Gallons (MG)) / # of days in the month] * 8.34

Attachment B
MWRA Advisory Board Comments 
NPDES Permit No. MA0103284 2023 Draft Permit 
Page 12 of 68 
15. Report in nanograms per liter (ng/L) for effluent and influent samples; report nanograms
per gram (ng/g) for sludge samples. Until there is an analytical method approved in 40
CFR Part 136 for PFAS, monitoring shall be conducted using Method 1633. Report in
NetDMR the results of all PFAS analytes required to be tested in Method 1633, as shown
in Attachment H. This reporting requirement for the listed PFAS parameters takes effect
the first full calendar quarter following six months after the effective date of the Permit. 
16. Report in nanograms per liter (ng/L) for effluent and influent samples; report nanograms
per gram (ng/g) for sludge samples. Until there is an analytical method approved in 40
CFR Part 136 for Adsorbable Organic Fluorine, monitoring shall be conducted using
Method 1621. This reporting requirement takes effect the first full calendar quarter
following six months after the effective date of the Permit. 
17. The Permittee shall conduct acute toxicity tests (LC50) and chronic toxicity tests (C-
NOEC) in accordance with test procedures and protocols specified in Attachment C and
D of this Permit. LC50 and C-NOEC are defined in Part II.E. of this Permit. The
Permittee shall perform an acute toxicity test using the Inland Silverside ( Menidia
beryllina ) and Mysid Shrimp ( Mysidopsis bahia ). The Permittee shall perform a chronic
toxicity test using the 1-hour fertilization test with the Sea Urchin ( Arbacia punctulata ) in
accordance with the test procedures and protocols specified in Attachment D . Toxicity
test samples shall be collected during the same weeks each time of calendar quarters
ending March 31st, June 30th, September 30th, and December 31st. The complete report
for each toxicity test shall be submitted as an attachment to the DMR submittal which
includes the results for that toxicity test. 
18. For Part I.A.1., Whole Effluent Toxicity Testing, the Permittee shall conduct the analyses
specified in Attachment C and D , Part VI. CHEMICAL ANALYSIS for the effluent
sample. If toxicity test(s) using the receiving water as diluent show the receiving water to
be toxic or unreliable, the Permittee shall follow procedures outlined in Attachment C
and D , Section IV., DILUTION WATER. Minimum levels and test methods are
specified in Attachment C and D , Part VI. CHEMICAL ANALYSIS. 
19. For Part I.A.1., Ambient Characteristic, the Permittee shall conduct the analyses specified
in Attachment C and D , Part VI. CHEMICAL ANALYSIS for the receiving water
sample collected as part of the WET testing requirements. Such samples shall be taken
from the receiving water at a point immediately outside of the permitted discharge’s zone
of influence at a reasonably accessible location, as specified in Attachment C and D .
Minimum levels and test methods are specified in Attachment C and D , Part VI.
CHEMICAL ANALYSIS. 
20. Monitoring and reporting for dissolved organic carbon (DOC) are not requirements of the
Whole Effluent Toxicity (WET) tests but are additional requirements. The Permittee may

Attachment B
MWRA Advisory Board Comments 
analyze the WET samples for DOC or may collect separate samples for DOC
concurrently with WET sampling.

Attachment B
MWRA Advisory Board Comments 
NPDES Permit No. MA0103284 2023 Draft Permit 
Page 13 of 68 
21. A pH and temperature measurement shall be taken of each receiving water sample at the
time of collection and the results reported on the appropriate DMR. These pH and
temperature measurements are independent from any pH and temperature measurements
required by the WET testing protocols.

Attachment B
MWRA Advisory Board Comments 
22. Sludge sampling shall be as representative as possible based on guidance found at 
https://www.epa.gov/sites/production/files/2018-11/documents/potw-sludge-sampling-
guidance-document.pdf .

Attachment B
MWRA Advisory Board Comments 
NPDES Permit No. MA0103284 2023 Draft Permit 
Page 14 of 68 
Part I.A., continued. 
2. The discharge shall not cause a violation of the water quality standards of the receiving
water. 
3. The discharge shall be free from pollutants in concentrations or combinations that, in the
receiving water, settle to form objectionable deposits; float as debris, scum or other matter to
form nuisances; produce objectionable odor, color, taste or turbidity; or produce undesirable
or nuisance species of aquatic life. 
4. The discharge shall be free from pollutants in concentrations or combinations that adversely
affect the physical, chemical, or biological nature of the bottom. 
5. The discharge shall not result in pollutants in concentrations or combinations in the receiving
water that are toxic to humans, aquatic life, or wildlife. 
6. The discharge shall be free from floating, suspended and settleable solids in concentrations or
combinations that would impair any use assigned to the receiving water. 
7. The discharge shall be free from oil and grease and petrochemicals. 
8. The Permittee must provide adequate notice to EPA and MassDEP of the following: 
a. Any new introduction of pollutants into the POTW from an indirect discharger
which would be subject to Part 301 or Part 306 of the Clean Water Act if it were
directly discharging those pollutants or in a primary industry category ( See 40 CFR
Part 122 Appendix A as amended) discharging process water; and 
b. Any substantial change in the volume or character of pollutants being
introduced into that POTW by a source introducing pollutants into the POTW at
the time of issuance of the Permit. 
c. For purposes of this paragraph, adequate notice shall include information on: 
(1) The quantity and quality of effluent introduced into the POTW; and 
(2) Any anticipated impact of the change on the quantity or quality of effluent
to be discharged from the POTW. 
9. Pollutants introduced into the POTW by a non-domestic source (user) shall not pass through
the POTW or interfere with the operation or performance of the POTW. 
10. In accordance with 40 CFR § 122.44(j)(1) the Permittee must identify, in terms of character
and volume, any Significant Industrial Users (SIUs) discharging into the POTW subject to

Attachment B
MWRA Advisory Board Comments 
Pretreatment Standards under section 307(b) of CWA and 40 CFR Part 403. SIUs
information shall be updated at a minimum of once per year or at that frequency necessary to

Attachment B
MWRA Advisory Board Comments 
NPDES Permit No. MA0103284 2023 Draft Permit 
Page 15 of 68 
ensure that all SIUs are properly permitted and/or controlled. The records shall be maintained
and updated as necessary. 
B. COMBINED SEWER OVERFLOWS (CSOs) 
Permittee and the CSO-responsible Co-Ppermittees are required to ensure that their respective
discharges from combined sewer overflow (CSO)) ourtfalls authorized under this Part and
activities in relation to the sewer system that each owns and operates complies with the terms
of this Part B and Part II. Neither Permittee nor any CSO-responsible Co-permittee shall be
responsible for another’s violations of this Part B or Part II. Moreover, in no event shall any
Co-permittee be responsible any violation of Part A. In the event of any conflict between this
paragraph and any other term or provision of this Permit, this paragraph shall control. 
1. Beginning on the effective date, the Permittee, MWRA, and the CSO-responsible Co-
permittees: Boston Water and Sewer Commission (BWSC), City of Cambridge, City of
Chelsea, and City of Somerville, are authorized to discharge stormwater/wastewater from the
combined sewer overflow (CSO) outfalls listed in Attachment A into the designated
receiving waters. These discharges are authorized only during “wet weather’ defined as any
period in which there is greater than 0.1 inches of rain and /or snow melt. 
2. Permittee’s and the CSO-responsible Co-permittee’s respective discharges of The effluent
discharged from these CSO outfalls areis subject to the following limitations: 
a. The discharges shall not cause or contribute to violations of federal or state Water
Quality Standards. 
b. The discharges shall receive treatment at a level providing Best Practicable Control
Technology Currently Available (BPT), Best Conventional Pollutant Control
Technology (BCT) to control and abate conventional pollutants and Best Available
Technology Economically Achievable (BAT) to control and abate non-
conventional and toxic pollutants. The EPA has made a Best Professional
Judgment (BPJ) determination that BPT, BCT, and BAT for combined sewer
overflow (CSO) control includes the implementation of Nine Minimum Controls
(NMC) specified below. These Nine Minimum Controls and the Nine Minimum
Controls Implementation Levels which are detailed further in Part I.B.2. are
requirements of this Permit and include: 
(1) Proper operation, and regular maintenance programs for the sewer
system, and the CSOs. 
(2) Maximum use of the collection system for storage of combined
wastewater and stormwater in order to minimize CSO discharges.

Attachment B
MWRA Advisory Board Comments 
(3) Review and, as appropriate, modify the pretreatment program to minimize
the adverse effects of CSO outfall discharges. 
(4) Maximization the proportion of the system’s wastewater, and combined
wastewater/stormwater, flow that is conveyed to the POTW for treatment. 
(5) Dry weather overflows from CSO outfalls are prohibited and must
be eliminated. 
(6) Minimize the discharge of solid and floatable materials in CSO outfall
discharges.

Attachment B
MWRA Advisory Board Comments 
NPDES Permit No. MA0103284 2023 Draft Permit 
Page 16 of 68 
(7) Implement pollution prevention programs that focus on contaminant
reduction activities. 
(8) Provide adequate notice to the public of CSO outfall occurrences and CSO
outfall impacts. 
(9) Monitor to effectively characterize CSO outfall impacts and the efficacy
of CSO controls. 
c. The authorized typical year discharge activations and volumes for the Boston Inner
Harbor CSO outfalls are limited as shown in Attachment I . Discharge frequencies
and volumes are expected to vary from year to year as a function of rainfall. 
d. The authorized typical year discharge activations and volumes for the Charles
River CSO outfalls are limited as shown in Attachment I . Discharge frequencies
and volumes are expected to vary from year to year as a function of rainfall. CSO
outfalls discharging to the Charles River Basin have been granted a variance
under the Massachusetts Water Quality Standards (WQS) through August 31,
2024. A copy of this determination letter for the variance extension is included as 
Attachment J . The conditions of this variance are incorporated into and are
enforceable elements of this permit. 
e. The authorized typical year discharge activations and volumes for the Alewife
Brook and Upper Mystic River CSO outfalls are limited as shown in Attachment
I . Discharge frequencies and volumes are expected to vary from year to year as a
function of rainfall. CSO outfalls discharging to the Alewife Brook/Upper Mystic
River Basin have been granted a variance under the Massachusetts Water WQS
through August 31, 2024. A copy of this determination letter for the variance
extension is included as Attachment K . The conditions of this variance are
incorporated into and are enforceable elements of this Permit. 
f. The Permit’s discharges must meet federal and state WQS subject to and consistent
with any water quality standards variances or variance extensions issued by
MassDEP and approved by EPA. 
3. Nine Minimum Controls Implementation Levels 
The Permittee, MWRA, and CSO-responsible Co-permittees: BWSC, City of Cambridge,
City of Chelsea and City of Somerville, shall continue to implement the Nine Minimum
Control Program (NMC) for their respective CSO discharges and infrastructure that each
owns and operates in accordance with the documentation provided to EPA and MassDEP
or as subsequently modified to enhance the effectiveness of controls. This implementation

Attachment B
MWRA Advisory Board Comments 
must include the controls identified in Part I.B.2.b.1-9 of this Permit plus other controls
the Permittee and CSO-responsible Co-permittees can reasonably undertake with respect
to their respective CSO discharges and infrastructure that each owns and operates as set
forth in the documentation. Within 1 year of the effective date of the

Attachment B
MWRA Advisory Board Comments 
NPDES Permit No. MA0103284 2023 Draft Permit 
Page 17 of 68 
permit, the Permittee and CSO-responsible Co-permittees shall each submit to
EPA and MassDEP through NetDMR an updated NMC program that reflects the
following requirements:. 
a. Permittee and the CSO-responsible Co-permittees shall routinely inspect Eeach
CSO structure/regulator, pumping station and/or tide gate that they respectively
own and operate shall be routinely inspected to ensure that they are in good
working condition and adjusted to minimize combined sewer discharges and tidal
surcharging. Such inspections shall occur monthly unless EPA approves a site-
specific inspection program which has been determined by EPA to provide an
equal level of effectiveness (NMC #1, 2 and 4). 
b. Permittee and CSO-responsible Co-permittees shall record Tthe following
inspection results shall be recordedfor each of their respective inspections: the
date and time of the inspection, the general condition of the facility, and whether
the facility is operating satisfactorily. If maintenance is necessary, the Permittee
or CSO-responsible Co-permittees shall record: the description of the necessary
maintenance, the date the necessary maintenance was performed, and whether the
observed problem was corrected. The Permittee or CSO-responsible Co-
permittee shall maintain all records of their respective inspections for at least
three (3) years. 
c. Annually, no later than March 31st , the Permittee and CSO-responsible Co-
permittees shall submit a certification to MassDEP and EPA which states that their
respective previous calendar year's monthly inspections were conducted, results
recorded, and records maintained. 
d. MassDEP and EPA have the right to inspect any CSO-related structure or outfall at
any time without prior notification to the Permittee and CSO-responsible Co-
Permittees. 
e. Discharges to the combined system of septage, holding tank wastes, or other
material which may cause a visible oil sheen or containing floatable material are
prohibited during wet weather when CSO outfalls may be active (NMC # 3, 6, and
7). 
f. Dry weather overflows (DWOs) are prohibited (NMC #5). All dry weather
sanitary and/or industrial discharges from Permittees’ and CSO-responsible Co-
permittees’ respective CSO outfalls must be reported to EPA and MassDEP
within 24 hours in accordance with the reporting requirements for plant bypass
(Paragraph D.1.e of Part II of this Permit).

Attachment B
MWRA Advisory Board Comments 
g. The Permittee and CSO-responsible Co-permittees shall quantify and record all
discharges from their respective combined sewer outfalls (NMC #9).
Quantification shall be through direct measurement or estimation. When
estimating, the Permittee and CSO-responsible Co-permittees shall make
reasonable efforts, (i.e., gaging, measurements) to verify the validity of their
respective estimation techniques. The following information must be recorded for
each combined sewer outfall for each discharge event:

Attachment B
MWRA Advisory Board Comments 
NPDES Permit No. MA0103284 2023 Draft Permit 
Page 18 of 68 
(1) Duration (hours) of discharge; 
(2) Volume (gallons) of discharge; and 
(3) National Weather Service precipitation data from the nearest gage where
precipitation is available at daily (24-hour) intervals and the nearest gage
where precipitation data at minimum of one-hour intervals is available to
the Permittee or CSO-responsible Co-permittees. 
(4) A description of whether the discharge activation and volume are in
accordance with the MWRA Final CSO Facilities Plan or as amended. 
h. Cumulative precipitation per discharge event shall be calculated. 
i. The Permittee and CSO-responsible Co-permittees shall maintain all of their
respective records of discharges from their respective CSO outfalls for at least
six (6) years after the effective date of this Permit, as it is collected, on an
ongoing basis. 
j. The Permittee and CSO-responsible Co-permittees shall install and maintain
identification signs for all combined sewer outfall structures (NMC # 8). The signs
must be located at or near the combined sewer outfall structures and be easily
readable by the public from the land and water. These signs shall be a minimum of
12 x 18 inches in size, with white lettering against a green background, and shall
contain the following information: 
(1) For CSO outfalls where MWRA is the responsible Permittee: 
WARNING:*
MASSACHUSETTS WATER RESOURCES AUTHORITY
WET WEATHER
SEWAGE DISCHARGE
OUTFALL (discharge serial number) 
(2) For CSO outfalls where BWSC is the CSO-responsible Co-permittee: 
WARNING:*
BOSTON WATER AND SEWER COMMISSION
WET WEATHER
SEWAGE DISCHARGE
OUTFALL (discharge serial number)

Attachment B
MWRA Advisory Board Comments 
(3) For CSO outfalls where the City of Cambridge is the CSO-responsible Co-
permittee:

Attachment B
MWRA Advisory Board Comments 
NPDES Permit No. MA0103284 2023 Draft Permit 
Page 19 of 68 
WARNING:*
CITY OF CAMBRIDGE
DEPARTMENT OF PUBLIC WORKS
WET WEATHER
SEWAGE DISCHARGE
OUTFALL (discharge serial number) 
(4) For CSO outfalls where the City of Chelsea is the CSO-responsible Co-
permittee: 
WARNING:*
CITY OF CHELSEA
DEPARTMENT OF PUBLIC WORKS
WET WEATHER
SEWAGE DISCHARGE
OUTFALL (discharge serial number) 
(5) For CSO outfalls where the City of Somerville is the CSO-responsible Co-
permittee: 
WARNING:*
CITY OF SOMERVILLE
DEPARTMENT OF PUBLIC WORKS
WET WEATHER
SEWAGE DISCHARGE
OUTFALL (discharge serial number) 
*For existing signs which otherwise meet the requirements of this section, the
word "Warning" need not be added. 
Where easements over property not owned by the Permittee or CSO-responsible
Co-permittees must be obtained to meet this requirement, the Permittee or CSO-
responsible Co-permittees will use its best efforts to identify the appropriate
landowners and obtain the necessary easements, to the extent practicable. 
The Permittee and CSO-responsible Co-permittees, to the extent feasible, shall
add a universal wet weather sewage symbol to each existing sign, or will place a
sign with a universal wet weather sewage symbol that is visible from the land and
water, unless there is already a warning sign written in a non-English language, or
will place additional signs in languages other than English based on notification
from the EPA. See Part I.K.3.

Attachment B
MWRA Advisory Board Comments 
k. In accordance with 314 CMR 16.05(3), each Permittee and CSO-responsible Co-
permittee shall install and maintain signage at public access points to waters

Attachment B
MWRA Advisory Board Comments 
NPDES Permit No. MA0103284 2023 Draft Permit 
Page 20 of 68 
affected by a potential discharge from the Permittee's or CSO-responsible Co-
permittee’s outfall by the date established in their respective approved CSO Public
Notification Plans. The locations for the signage shall be established in the
Permittee's or CSO-responsible Co-permittee’s respective approved CSO Public
Notification Plans based on consultation with boards of health or health
departments in the municipalities directly impacted by the discharge. Each sign
shall identify: 
(1) The existence of the outfall; 
(2) The permittee; 
(3) Information about weather events that may cause a discharge; 
(4) A warning of the potential threat to public health by recreating in, or
using waters and shores affected by a discharge; and 
(5) Information for the public to subscribe to notifications about discharges in
local area waters. 
Signage shall be developed using a template provided by MassDEP and be able to
provide timely information about ongoing discharges to allow municipal boards of
health and health departments to meet the requirements of 314 CMR 16.09(5). For
discharges directly affecting neighborhoods identified as environmental justice
populations due to lacking English language proficiency, signage shall provide
access to translations in the language(s) most appropriate for those neighborhoods
and shall utilize universal symbols. 
l. The City of Cambridge may use the activation of Outfall CAM401B as a general
indicator of the onset of CSO outfall discharges which would trigger the notice in
accordance with 314 CMR 16.00, Notification Requirements to Promote Public
Awareness of Sewage Pollution, unless there is evidence that a different CSO
outfall activated before CAM401B. (NMC #8). 
m. Public Notification Plan 
The Permittee and CSO-responsible Co-permittees must implement their respective
preliminary and final CSO Public Notification Plans as approved by MassDEP and shall
meet all other applicable requirements of 314 CMR 16.00. 
https://www.mass.gov/doc/314-cmr-1600-notification-requirements-to-promote-public-
awareness-of-sewage-pollution-1/download

Attachment B
MWRA Advisory Board Comments 
4. The Permittee and each CSO-responsible Co-permittee may consolidate CSO reports which
are on similar reporting schedules. 
5. Nine Minimum Controls Reporting Requirement

Attachment B
MWRA Advisory Board Comments 
NPDES Permit No. MA0103284 2023 Draft Permit 
Page 21 of 68 
a. Annually, no later than April 30th , the Permittee and each CSO-responsible Co-
permittees shall submit a report into NetDMR which includes the following
information: 
b. Activation frequency and discharge volumes for each CSO outfall listed on 
Attachment A for which Permittee or the CSO-responsible Co-permittee is
responsible during the previous calendar year. For each day of an MWRA CSO
discharge event, the MWRA Report shall include the daily flow at DITP and note
whether there was a bypass of secondary treatment, and the volume bypassed. 
c. For any Permittee or CSO-responsible Co-permittees with CSO treatment
facilities, a compilation of the data for CSO events for which sampling
was conducted pursuant to section I.B.6 of this Permit. 
d. Precipitation during the previous year for each day, including total rainfall, peak
intensity, and average intensity. 
e. Status of the implementation of CSO outfall abatement work for which the
Permittee or CSO-responsible Co-permittees is directly responsible in accordance
with the MWRA Final CSO Facilities Plan, the Federal Court Order, as amended
and any related subsequent documents and the requirements of a CSO Variance.
The authorized typical year CSO discharge activations and volumes can be found
in Attachment I . 
f. For the outfalls listed in Attachment A , provide the following information in the
Annual Report for year 3 and every two years thereafter using the updated MWRA
model (or equivalent) for comparison: 
(1) A comparison between the precipitation for the previous year and the
precipitation in the typical year under future planned conditions used in
the MWRA Final CSO Facilities Plan or “Notice of Project Change”
document, or subsequent document, whichever is appropriate. This
comparison shall include the number of events and size of events
(including recurrence interval). 
i. For each CSO outfall that the Permittee or CSO-responsible
Co-permittee owns or operates, a comparison between the
activation volume and frequency for the previous year and
the volume and frequency expected during a typical year
under future planned conditions.

Attachment B
MWRA Advisory Board Comments 
ii. For each CSO event from one or more outfalls that the
Permittee or CSO-responsible Co-Ppermittee owns or
operates, an estimate of the recurrence interval of the storm
event, using the rainfall data collected and the information
included in the NOAA Atlas 14, or other technical reference
for defining storm event recurrence.

Attachment B
MWRA Advisory Board Comments 
NPDES Permit No. MA0103284 2023 Draft Permit 
Page 22 of 68 
iii. An evaluation of whether the Permittee’s or CSO-responsible Co-
permittees’ respective CSO outfall activation volumes and
frequencies for the previous year are in accordance with the
estimates in the MWRA Final CSO Facilities Plan or as
amended by the Court, given the precipitation which occurred
during the year, and the CSO outfall abatement activities which
have been implemented. Where CSO outfall discharges are
determined to be greater than the activation frequency or
volume in either document above, the Permittee or CSO-
responsible Co-permittees shall include their assessment of
such result, a discussion of remaining CSO outfall abatement
activities and an assessment of the impact of those projects on
attaining the level of CSO outfall control identified in the
relevant document, or any amendments thereto. 
6. Combined Sewer Overflow Outfall Monitoring 
For each combined sewer overflow outfall listed in Attachment A of this Permit, the
Permittee or CSO-responsible Co-permittees must monitor the following for their
respective outfalls: 
Parameters 
Reporting
Requirements Monitoring Requirements 
Total Monthly Measurement
Frequency 
Sample
Type 
Total Flow Report Gallons Daily, when
discharging Continuous 
Total Flow Duration (Duration of
flow through CSO discharge) Report Hours Daily, when
discharging Continuous 
Number of CSO Discharge Events Report Monthly
Count 
Daily, when
discharging Count 
a. For Total Flow, measure the total flow discharged from each CSO outfall during
the month. For Total Flow Duration, report the total duration (hours) of discharges
for each CSO outfall during the month. 
b. For those months when a CSO discharge does not occur, the Permittee and
responsible Co-permittees must indicate "no discharge" for the outfall for which
data was not collected.

Attachment B
MWRA Advisory Board Comments 
c. This information shall be submitted with the annual report required by Part I.B.5 of
this Permit. 
7. Combined Sewer Overflow Outfalls Limitations and Monitoring for the MWRA CSO
Treatment Facilities (Outfalls MWR201, MWR203, MWR205, MWR205A and MWR215)

Attachment B
MWRA Advisory Board Comments 
NPDES Permit No. MA0103284 2023 Draft Permit 
Page 23 of 68 
a. In addition to the requirements for all CSO outfalls listed above, during the period
beginning on the effective date, the Permittee is authorized to discharge treated
effluent through Outfalls MWR201, MWR203, MWR205, MWR205A and
MWR215. Outfalls MWR201 and MWR205A discharge to Class B waters with
CSO variances. Outfalls MWR203, MWR205 and MWR215 discharge into Class
SB(CSO) waters. These discharges are authorized only during wet weather (i.e.,
any period in which there is greater than 0.1 inches of rain and/or snow melt). The

Attachment B
MWRA Advisory Board Comments 
discharge shall be limited and monitored as specified below; the receiving water
and the influent shall be monitored as specified below.

Attachment B
MWRA Advisory Board Comments 
NPDES Permit No. MA0103284 2023 Draft Permit 
Page 24 of 68 
b. CSO Effluent Limits 
Effluent Characteristic 
Effluent Limitation Monitoring
Requirements 22,23,24 
Average
Monthly 
Maximum
Daily 
Measurement
Frequency 
Sample
Type 25 
Flow 26 Report Report Per Discharge
Event Recorder 
Rainfall/Precipitation 27 Report Report Per Discharge
Event 
Total 
BOD 5 
Outfalls MWR201, MWR205A, MWR203, 
MWR205, MWR215 
Report mg/L and
lb/day 
Report mg/L and
lb/day 
4/Year 28 Event 
Composite 
TSS 
Outfalls MWR201, MWR205A, MWR203, 
MWR205, MWR215 
Report mg/L and
lb/day 
Report mg/L and
lb/day 
4/Year 28 Event 
Composite 
pH Range 29 
Outfalls MWR201, MWR205A 
Outfalls MWR203, MWR205, MWR215 
6.5 - 8.3 S.U.
6.5 - 8.5 S.U. 4/Year 28 Grab 
Total Residual Chlorine 30 
Outfall MWR201
Outfall MWR203
Outfall MWR205
Outfall MWR205A
Outfall MWR215 
0.055 mg/L
0.045 mg/L
0.075 mg/L
0.01 mg/L
0.015 mg/L 
0.1 mg/L
0.078 mg/L
0.13 mg/L
0.02 mg/L
0.026 mg/L 
4/Year 28 Grab

Attachment B
MWRA Advisory Board Comments 
E. coli 30 
Outfalls MWR201, MWR205A 126 cfu/100 mL 410 cfu/100 mL 4/Year 28 Grab

Attachment B
MWRA Advisory Board Comments 
NPDES Permit No. MA0103284 2023 Draft Permit 
Page 25 of 68 
Effluent Characteristic 
Effluent Limitation Monitoring
Requirements 22,23,24 
Average
Monthly 
Maximum
Daily 
Measurement
Frequency Sample
Type 25

Attachment B
MWRA Advisory Board Comments 
Enterococcus 30 
Outfalls MWR203, MWR205 and MWR215 35 cfu/100 mL 130 cfu/100 mL 4/Year 28 Grab

Attachment B
MWRA Advisory Board Comments 
NPDES Permit No. MA0103284 2023 Draft Permit 
Page 26 of 68 
Whole Effluent Toxicity (WET) Testing 
LC 50 
Outfalls MWR201, MWR205A 31,32 
Outfalls MWR203, MWR205, MWR215 33,34 
Report
Report 
Report
Report 
2/Year 
Event 
Composite 
Salinity 
Outfalls MWR203, MWR205, MWR215 --- Report ppt 2/Year 
Event 
Composite 
Ammonia Nitrogen --- Report mg/L 2/Year 
Event 
Composite 
Total Cadmium --- Report mg/L 2/Year 
Event 
Composite 
Total Copper --- Report mg/L 2/Year 
Event 
Composite 
Total Nickel --- Report mg/L 2/Year 
Event 
Composite 
Total Lead --- Report mg/L 2/Year 
Event 
Composite 
Total Zinc --- Report mg/L 2/Year 
Event 
Composite

Attachment B
MWRA Advisory Board Comments 
Total Organic Carbon --- Report mg/L 2/Year 
Event 
Composite

Attachment B
MWRA Advisory Board Comments 
NPDES Permit No. MA0103284 2023 Draft Permit 
Page 27 of 68 
Footnotes: 
22. All samples shall be collected in a manner to yield representative data. A routine
sampling program shall be developed in which samples are taken at the same
location, and same time frame. Occasional deviations from the routine sampling
program are allowed, but the reason for the deviation shall be documented as an
electronic attachment to the applicable discharge monitoring report. The Permittee
shall report the results to the EPA and MassDEP of any additional testing above
that required herein, if testing is in accordance with 40 CFR Part 136. 
23. In accordance with 40 CFR § 122.44(i)(1)(iv), the Permittee shall monitor 
according to sufficiently sensitive test procedures (i.e., methods) approved under
40 CFR Part 136 or required under 40 CFR chapter I, subchapter N or O, for the
analysis of pollutants or pollutant parameters (except WET). A method is
“sufficiently sensitive” when: 1) The method minimum level (ML) is at or below
the level of the effluent limitation established in the permit for the measured
pollutant or pollutant parameter; or 2) The method has the lowest ML of the
analytical methods approved under 40 CFR Part 136 or required under 40 CFR
chapter I, subchapter N or O for the measured pollutant or pollutant parameter.
The term “minimum level” refers to either the sample concentration equivalent
to the lowest calibration point in a method or a multiple of the method detection
limit (MDL), whichever is higher. Minimum levels may be obtained in several
ways: They may be published in a method; they may be based on the lowest
acceptable calibration point used by a laboratory; or they may be calculated by
multiplying the MDL in a method, or the MDL determined by a laboratory, by a
factor. 
24. When a parameter is not detected above the ML, the Permittee must report the
data qualifier signifying less than the ML for that parameter (e.g., < 50 μ g/L, if
the ML for a parameter is 50 μ g/L). For reporting an average based on a mix of
values detected and not detected, assign a value of "0" to all non-detects for that
reporting period and report the average of all the results. 
25. A "grab" sample, for the purposes of this section, is an individual sample 
collected in a period of less than 15 minutes. A grab sample will be taken within
the first two hours of the start of a discharge, and every hour thereafter for the
duration of the discharge. 
A "composite" sample, for the purposes for this section, is a time-weighted
composite sample. Sampling will begin within the first two hours of the start of a

Attachment B
MWRA Advisory Board Comments 
discharge and aliquots taken no more than one hour apart for the duration of the
discharge, not to exceed twenty-four (24) hours. The aliquots will be of equal

Attachment B
MWRA Advisory Board Comments 
NPDES Permit No. MA0103284 2023 Draft Permit 
Page 28 of 68 
volume, comprising a time-weighted composite as defined in Part II Standard
Conditions. 
26. Report the peak flow rate, duration and volume for each discharge event. 
27. Report the National Weather Service data for Boston per discharge event. Report
intensity, duration and volume of each rain event. 
28. Sampling shall be concentrated during the “critical” use periods. The Permittee
shall sample one Spring event (March 1st – April 30th), two Summer events (May
1st – August 31st) and one Fall event (September 1st – October 31st). At least one
of the sampled events shall include a period of discharge from MWR205A. The
Permittee shall report “9” on its DMR during months when sampling is not
conducted. 
29. The pH shall be within the specified range at all times. The minimum and
maximum pH sample measurement values for the month shall be reported in
standard units (S.U.). 
30. The Permittee shall minimize the use of chlorine while maintaining adequate
bacterial control. Monitoring for total residual chlorine (TRC) is only required for
discharges which have been previously chlorinated, or which contain residual
chlorine. 
TRC samples must be collected concurrently with the E.coli and/or 
Enterococcus samples. 
Chlorination and dechlorination systems shall include an alarm system for
indicating system interruptions or malfunctions. Any interruption or malfunction
of the chlorine dosing system that may have resulted in levels of chlorine that
were inadequate for achieving effective disinfection, or interruptions or
malfunctions of the dechlorination system that may have resulted in excessive
levels of chlorine in the final effluent shall be reported with the monthly DMRs.
The report shall include the date and time of the interruption or malfunction, the
nature of the problem, and the estimated amount of time that the reduced levels of
chlorine or dechlorination chemicals occurred. 
Process Control TRC: For each discharge event, the Permittee must maintain a
record of process control TRC before dechlorination, using the TRC analyzer
(measured continuously) or with hourly grab samples).

Attachment B
MWRA Advisory Board Comments 
The discharge event maximum is the hourly maximum during the discharge event.

Attachment B
MWRA Advisory Board Comments 
NPDES Permit No. MA0103284 2023 Draft Permit 
Page 29 of 68 
31. The Permittee shall conduct acute toxicity tests (LC50) two times per year, once
in Quarter 2 (April 1 - June 30), and once in Quarter 3 (July 1 - Sep 30). The
LC50 is defined in Part II.E. of this Permit. The Permittee shall perform an acute
toxicity test using the daphnid ( Ceriodaphnia dubia ) and the fathead minnow
( Pimephales promelas ). Toxicity test samples shall be collected during the first
flush or as a composite over the duration of the overflow, not to exceed 24
hours. The tests must be performed in accordance with test procedures and
protocols specified in Attachment E of this Permit. 
If the discharge fails an LC50 = 100% toxicity test, the Permittee will perform a
second acute toxicity test within 30 days, or if weather does not permit, as soon
as possible. If the discharge fails the second LC50 = 100% toxicity test, the 
Permittee will submit a report to EPA discussing the results of the first two
toxicity tests and the concomitant priority pollutant testing. 
The complete report for each toxicity test shall be submitted as an attachment to 
the DMR submittal which includes the results for that toxicity test. 
32. For Part I.B.6., Whole Effluent Toxicity Testing, the Permittee shall conduct the
analyses specified in Attachment E , Part VI. CHEMICAL ANALYSIS for the
effluent sample. If toxicity test(s) using the receiving water as diluent show the
receiving water to be toxic or unreliable, the Permittee shall follow procedures
outlined in Attachment E , Section IV., DILUTION WATER. Minimum levels
and test methods are specified in Attachment E , Part VI. CHEMICAL
ANALYSIS. 
33. The Permittee shall conduct acute toxicity tests (LC50) two times per year, once
in Quarter 2 (April 1 - June 30), and once in Quarter 3 (July 1 - Sep 30). The
LC50 is defined in Part II.E. of this Permit. The Permittee shall perform an acute
toxicity test using the Inland Silverside ( Menidia beryllina ) and Mysid Shrimp
( Mysidopsis bahia ) in accordance with test procedures and protocols specified in 
Attachment C of this Permit. The Permittee shall perform a chronic toxicity test
using the 1-hour fertilization test with the Sea Urchin ( Arbacia punctulata ) in
accordance with test procedures and protocols specified in Attachment D of this
Permit. . Toxicity test samples shall be collected during the first flush or as a
composite over the duration of the overflow, not to exceed 24 hours. 
34. The complete report for each toxicity test shall be submitted as an attachment to
the DMR submittal which includes the results for that toxicity test. For Part I.B.6.,
Whole Effluent Toxicity Testing, the Permittee shall conduct the analyses
specified in Attachments C and D , Part VI. CHEMICAL ANALYSIS for the

Attachment B
MWRA Advisory Board Comments 
effluent sample. If toxicity test(s) using the receiving water as diluent show the
receiving water to be toxic or unreliable, the Permittee shall follow procedures

Attachment B
MWRA Advisory Board Comments 
NPDES Permit No. MA0103284 2023 Draft Permit 
Page 30 of 68 
outlined in Attachments C and D , Section IV., DILUTION WATER. Minimum
levels and test methods are specified in Attachment C and D , Part VI.
CHEMICAL ANALYSIS. 
C. UNAUTHORIZED DISCHARGES 
1. This Permit authorizes discharges only from the outfalls listed in Part I.A.1, Attachment A 
and Part I.B.1 in accordance with the terms and conditions of this Permit. Discharges of
wastewater from any other point sources, including sanitary sewer overflows (SSOs), are not
authorized by this Permit. The Permittee, CSO-responsible Co-permittees and Co-permittees
must provide verbal notification to EPA and MassDEP within 24 hours of becoming aware of
any unauthorized discharge from the infrastructure that they respectively own and operate,
and submit a written report within 5 days, in accordance with Part II.D.1.e (24-hour
reporting). Providing that it contains the information required in Part II.D.1.e, submission of
the MassDEP SSO Reporting Form (described in I.C.3 below) may satisfy the requirement
for a written report. See Part I.J below for reporting requirements. 
2. The Permittee, CSO-responsible Co-permittees and Co-permittees must provide notification
to the public within 24 hours of becoming aware of any unauthorized discharge from the
infrastructure that they respectively own and operate, except SSOs that do not impact a
surface water or the public, on a publicly-available website, and it shall remain on the
website for a minimum of 12 months. Such notification shall include the location (including
latitude and longitude) and description of the discharge; estimated volume; the period of
noncompliance, including exact dates and times, and, if the noncompliance has not been
corrected, the anticipated time it is expected to continue. 
3. Written notification of SSOs to MassDEP shall be made on its SSO Reporting Form (which
includes MassDEP Regional Office telephone numbers). The reporting form and instruction
for its completion may be found on-line at https://www.mass.gov/how-to/sanitary-sewer-
overflowbypassbackup-notification . For SSOs and discharges of partially treated wastewater
that are defined in 314 CMR 16.03, the Permittee, CSO-responsible Co-permittees, and Co-
permittees must meet all requirements of 314 CMR 16.00, including, but not limited to,
public notification within two hours of discovery of the discharge, reporting into MassDEP’s
electronic reporting system, and posting on the Permittee’s, CSO-responsible Co-
permittee’s, or Co-permittee’s website. 
4. Bypassing of wastewater flows is not authorized. Bypass is subject to enforcement discretion
in situations where determined necessary to prevent loss of life or damage to the plant. The
Clean Water Act ("CWA") and EPA's 1994 CSO Control Policy state that the intentional
diversion of waste streams from any portion of a treatment facility, including secondary
treatment, is a bypass. EPA regulations at 40 CFR 122.41 (m) further detail the conditions
under which EPA will not initiate an enforcement action for bypasses, including: (1) that the

Attachment B
MWRA Advisory Board Comments 
bypass was unavoidable to prevent loss of life, personal injury, or severe property damage;
and (2) there were no feasible alternatives to the bypass. Reporting of secondary bypass
events shall be carried out as set forth in provisions of Section I.A.1, Footnote 6 of this
permit.

Attachment B
MWRA Advisory Board Comments 
NPDES Permit No. MA0103284 2023 Draft Permit 
Page 31 of 68 
D. NOTICE OF ELIMINATION 
The Permittee and CSO-responsible Co-permittees shall give notice of elimination or change in
status of any CSO outfall listed in Attachment A that they respectively own and operate as
soon as possible in writing to EPA and MassDEP. 
E. OPERATION AND MAINTENANCE 
1. Wastewater Treatment Facility 2 
Operation and maintenance (O&M) of the wastewater treatment facility owned and/or operated
by the Permittee shall be in compliance with 40 CFR § 122.41 (d) and (e) and the terms and
conditions of the Part II. Standard Conditions, B. Operation and Maintenance of Pollution
Controls which is attached to this Permit. 
a. WWTF Major Storm and Flood Events Plan. Within 12 months of the effective date of 
this Permit, the Permittee shall develop and submit a WWTF Major Storm and Flood
Events Plan and begin to implement mitigation measures consistent with the schedule
contained in this paragraph. The Plan shall contain three components: (1) an asset
vulnerability evaluation, (2) a systemic vulnerability evaluation 3 of the assets, and (3) a
mitigation measures alternatives analysis. The Plan shall include resiliency and
implementation planning informed by an evaluation of all WWTF vulnerabilities to
major storm and flood events. 4 The planning process shall be iterative, and re-
evaluations shall be conducted: (1) if on- or off-site structures are added, removed or
significantly changed in any way that will impact the vulnerability of the WWTF; and
(2) as data sources used for such evaluations are revised, or generated. At a minimum,
the Plan must take future conditions into consideration, specifically the midterm (i.e., 
2 Wastewater Treatment Facility means any devices and systems used in the storage, treatment, recycling and
reclamation of municipal sewage or industrial wastes of a liquid nature. It does not include sewers, pipes and other
conveyances to the wastewater treatment facility. 
3 To determine the vulnerabilities to the facilities from major storm and flood events, you must conduct the
evaluation using, at a minimum, the worst-case data relating to changes in precipitation, sea level rise, extreme
weather events, coastal flooding, inland flooding, sewer flow and inflow and infiltration and relevant to the facilities
from: 1) the data generated by the 13 federal agencies that conduct or use research on global change that contributed
to the latest National Climate Assessment produced by the U.S. Global Change Research Program (USGCRP); 2)
climate data generated by the Commonwealth of Massachusetts; and 3) resiliency planning completed by the
municipality in which a given facility is located (i.e., City of Boston) and incorporate the results of the evaluation in
a manner that demonstrates that the control measures taken are precautionary and sufficiently protective. Evaluation
must be completed by a qualified person on a five-year basis considering: 1) historical observations from all years
the Permittee has operated the facility prior to this permit’s term; 2) set midterm (i.e., 20-30 years) and long-term
(i.e., 80-100 years) ranges. 
4 “Major storm and flood events” refer to instances resulting from major storms such as hurricanes, extreme/heavy
precipitation events, and pluvial, fluvial, and flash flood events such as high-water events, storm surge, and high-tide
flooding. “Extreme/heavy precipitation” refers to instances during which the amount of rain or snow experienced in a
location substantially exceeds what is normal. What constitutes a period of heavy precipitation varies according to

Attachment B
MWRA Advisory Board Comments 
location and season. “Extreme/heavy precipitation” does not necessarily mean the total amount of precipitation at a
location has increased, but just that precipitation is occurring in more intense or more frequent events.

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MWRA Advisory Board Comments 
NPDES Permit No. MA0103284 2023 Draft Permit 
Page 32 of 68 
20-30 years) and long-term (i.e., 80-100 years) and, in the case of sea level change, the
plan must consider extreme sea level change. The Plan shall be updated at least every
five (5) years from the effective date of this Permit and must take future conditions
into consideration. 5 
(1) Component 1: Asset Vulnerability Evaluation . This first component of the 
WWTF Major Storm and Flood Events Plan must assess the vulnerability of
individual WWTF-related assets. The Permittee may find EPA’s guide:
Flood Resilience: A Basic Guide for Water and Wastewater Utilities 6 and
EPA’s website 7 Creating Resilient Water Utilities (CRWU) helpful for
completing this component. 
The Asset Vulnerability Evaluation shall include, at a minimum, the
following: 
i. Description of planning priorities related to major storm
and flood event vulnerabilities presented by the location of
the WWTF (e.g., proximity to waterbodies which may
cause flooding). 
ii. Identification of all assets related to the WWTF (e.g., 
buildings, laboratories and offices, WWTF, septage collection
facilities, etc.), the elevation of each asset, and if the asset falls
into the 100-year flood map or the 500-year flood map; 8 
iii. Description of structural improvements, either completed or
planned, and/or other mitigation measures 9 designed to
minimize 10 the impacts of major storm and flood events to each
specific asset identified above. 
The Permittee shall consider, at a minimum, the following measures: 
5 It will be advantageous to the Permittee to consider low, medium, high and extreme levels of sea level change to
determine priority assets and plan for increasingly protective mitigation measures. 
6 https://www.epa.gov/sites/default/files/2015-08/documents/flood_resilience_guide.pdf 
7 https://www.epa.gov/crwu 
8 See https://www.epa.gov/sites/default/files/2015-08/documents/flood_resilience_guide.pdf for a basic guide to
flood resiliency for water and wastewater utilities. 
9 Mitigation measure can be, for example, an emergency planning activity, equipment modification/upgrade or new
capital investment/construction project.

Attachment B
MWRA Advisory Board Comments 
10 For the purposes of this provision, the term “minimize” means to reduce and/or eliminate to the extent achievable
the impacts to the facilities.

Attachment B
MWRA Advisory Board Comments 
NPDES Permit No. MA0103284 2023 Draft Permit 
Page 33 of 68 
(a) Construction of flood barriers to protect infrastructure
or reinforce existing structures to withstand flooding
and additional exertion of force; 
(b) Establish remote locations for operations, equipment,
records and data backups; 
(c) Plan and establish alternative or on-site power supply; 11 
(d) Relocate facilities and/or infrastructure to higher elevations; 
(e) Catalog emergency resources used during a major storm
or flood event; 
(f) Develop emergency response plans; 
(g) Establish contracts for backup supplies of critical chemicals; 
(h) Establish mutual aid agreements with neighboring utilities; 
(i) Integrate long-term risks into capital improvement plans; 
(j) Participate in community planning and
regional collaborations; 
(k) Conduct staff training for implementing your emergency
procedures at regular intervals; 
(l) When designing new or replacement facilities, strive to locate
facilities above the relative base flood elevation 12 for both the
1% (100-year) and 0.2 % (500-year) chance storm events. 
iv. Identify the source of data used to assess vulnerabilities
to major storm and flood events. 
v. Identify potential funding sources 13 for resilience planning and
implementation. (e.g., EPA, FEMA, MassDEP, capital
planning, etc.). 
(2) Component 2: Systemic Vulnerability Evaluation . Upon completing
assessment of the vulnerabilities of individual assets, the Permittee shall
evaluate the vulnerability of its WWTF system as a whole. This second
component of the evaluation shall include, at a minimum, a systematic 
11 The Permittee shall clearly document measures taken specifically to manage energy system disruptions, such as a
general power outage, as well as document whether and, if so, to what extent, power supply adequate to ensure safe
and reliable operations of the facility is threatened during a major storm or flood. They shall clearly document
measures that have been taken to address any risks the facility faces of losing power during a major storm or flood in
a manner that could result in environmental or public health impacts. 
12 For activities proposed for MA facilities within Areas Subject to Protection under M.G.L. c. 131, § 40 or the 100-
foot buffer zone, the Base Flood Elevation is defined at 310 CMR 10.04, Definitions of Special Flood Hazard Area,
Velocity Zone, and Coastal High Hazard Area, Land Subject to Coastal Storm Flowage at 310 CMR 10.36 and

Attachment B
MWRA Advisory Board Comments 
Bordering Land Subject to Flooding, and Isolated Land Subject to Flooding at 310 CMR 10.57. Also refer to the
Massachusetts State Building Code for any other required standards related to Base Flood Elevation. 
13 See https://www.epa.gov/fedfunds

Attachment B
MWRA Advisory Board Comments 
NPDES Permit No. MA0103284 2023 Draft Permit 
Page 34 of 68 
vulnerability evaluation for each asset identified in Part I.E.1.a.(1),
including the following: 
i. Define the criticality of the asset to overall treatment
facility operations. 14 
ii. Identify the highest 15 priority assets for the facility/system and
the measures taken (or planned) to reduce facility vulnerability
to risks that could degrade overall system operations in a
manner that would result in environmental or public health
impacts. 
(3) Component 3: Mitigation Measures Alternatives Evaluation. Upon
completing assessment of the vulnerabilities of the WWTF system as a
whole, the Permittee shall provide an assessment of asset-specific
mitigation measures, and/or, if appropriate, combinations of mitigation
measures to minimize the impact of major storm and flood events. The
Permittee shall then select the most effective mitigation measure(s) and
include a schedule for implementation. This third component shall
include, at a minimum, the following: 
i. An evaluation of mitigation measure alternatives including
a cost-effectiveness analysis and a review of technical,
environmental, and institutional factors. 
ii. For each mitigation measure, quantitatively document
(including assumptions and methodologies) the residual risk
today, in the midterm (i.e., 20-30 years) and the long-term (i.e.,
80-100 years). The evaluation should include estimates of
which customers and geographic areas bear the residual risk
after implementation of the mitigation measures. Residual risk
is a term that refers to the risk remaining for an asset or system,
after mitigation measures are taken. 
iii. Selection of mitigation measures to be undertaken, including: 
14 For example, an asset like a pumping station or headworks is often scored “high” for criticality, as the safe and
reliable operation of many assets during a major storm or flood depend upon the continued operation of that
particular asset. If a pump station is degraded or fails, many other assets operations can degrade or fail, resulting in
environmental or public health impacts.

Attachment B
MWRA Advisory Board Comments 
15 Based on the combined assessment of asset-level vulnerability today and in the midterm (i.e., 20-30 years) and
long-term (i.e., 80-100 years), the criticality of that asset’s performance to the operations of the system today and in
the midterm (i.e., 20-30 years) and long-term (i.e., 80-100 years).

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MWRA Advisory Board Comments 
NPDES Permit No. MA0103284 2023 Draft Permit 
Page 35 of 68 
(a) a schedule 16 of implementation for each selected mitigation
measure; 17 and 
(b) a map showing the location of planned mitigation measure. 
(4) Annual Report . The Permittee shall submit an Annual Operation and
Maintenance Report on the WWTF Major Storm and Flood Events Plan 
implementation and results for the prior calendar year including
documenting any changes to the WWTF or other assets that may impact
the current vulnerability evaluation. The first annual report is due the first
March 31 following submittal of the Wastewater Treatment Facility Major
Storm and Flood Events Plan and shall be included with the annual report
required in Part I.E.3. below. 
2. Sewer System 
Operation and maintenance (O&M) of the sewer system owned and operated, respectively, by the
Permittee, CSO-responsible Co-permittees: Boston Water and Sewer Commission (BWSC), City
of Cambridge, City of Chelsea and City of Somerville; and each of the Co-permittee
municipalities listed in Attachment B shall be in compliance with the terms and conditions of
Part C, Part D, Part E, Part F and Part J of this Permit and the General Requirements of Part II, of
this Permit for only its own infrastructure, activities and required reporting with respect to the
portions of the collection system that it owns or operates. 
No Permittee, CSO-responsible Co-permittee, or Co-permittee shall be responsible for violations
of Part B, Part C, Part D, Part E, Part F and Part J of this Permit and/or the General Requirements
of Part II committed by another Permittee Permittee, CSO-responsible Co-permittee, or Co-
permittee relative to the portions of the collection system owned and operated by such other
Permittee, CSO-responsible Co-permittee, or Co-permitteePermittee. CSO-responsible Co-
permittees and Co-permittees are also not responsible for any violations of Parts A, D, G, H, I, J,
or K committed by Permittee. In the event of any conflict between the above provisions and any
other term or provision of this Permit, the above provisions shall control. As set forth below, Tthe
Permittee, CSO-responsible Co-permittees, and Co-permittees are required to complete the
following activities for the respective portions of the collection system which they operate: 
16 In describing the schedule to implement mitigation measures, the Permittee shall clearly document which
mitigation measures identified in the Plan have or have not been integrated into that system’s capital planning
process. A mitigation measure is integrated when a budget line item in that system’s current and adopted capital plan

Attachment B
MWRA Advisory Board Comments 
clearly identifies the year of completion and expenditure that has been budgeted and approved to complete that
mitigation measure. 
17 For all measures considered, the Permittee must document in the Plan the factual basis (i.e., the maps, data sets
and calculations for the analysis), for either implementing or not implementing the measure. The factual basis and
analysis must be presented in sufficient detail to allow EPA, the public, or an independent qualified person to
evaluate the reasonableness of the decision. For measures already in place, including requirements from state, local
or federal agencies, a description of the measures and how they meet the requirement(s) of this Permit must be
documented in the Plan.

Attachment B
MWRA Advisory Board Comments 
NPDES Permit No. MA0103284 2023 Draft Permit 
Page 36 of 68 
a. Maintenance Staff 
The Permittee, the CSO-responsible Co-permittees and Co-permittees shall provide an
adequate staff to carry out the operation, maintenance, repair, and testing functions
required to ensure compliance with the terms and conditions of this Permit that apply,
respectively, to the Permittee, CSO-responsible Co-permittees, or Co-permittees.
Provisions to meet this requirement shall be described in the Sewer System O&M Plan
required pursuant to Part I.E.2.e below. 
b. Preventive Maintenance Program 
The Permittee, CSO-responsible Co-permittees and Co-permittees shall maintain an
ongoing preventive maintenance program to prevent overflows and bypasses caused by
malfunctions or failures of the sewer system infrastructure that each owns and operates.
The program shall include an inspection program designed to identify all potential and
actual unauthorized discharges from the sewer system that each Permittee, CSO-
responsible Co-permittee, and Co-permittee owns and operates. Plans and programs to
meet this requirement shall be described in the Sewer System O&M Plan required
pursuant to Part I.E.2.e. below. 
c. Infiltration/Inflow 
(1) The Permittee, CSO-responsible Co-permittees and Co-permittees shall
control infiltration and inflow (I/I) into the sewer system that each owns
and operates as necessary to prevent high flow related unauthorized
discharges from their collection systems and high flow related
violations of the wastewater treatment plant's effluent limitations. Plans
and programs to control I/I shall be described in the Sewer System
O&M Plan required pursuant to Part I.E.2.e. below. 
(2) The Permittee, MWRA, shall update its existing I/I Reduction Plan. As
part of the update, the Permittee must identify the goals and strategies of
the 2002 Regional I/I Reduction Plan that have been completed and justify
the goal or strategy be removed from the updated Plan. Additionally, the
Permittee shall also consider new steps, strategies, and technologies to be
implemented in addressing I/I. Finally, the Permittee shall include a
discussion of historical SSO locations and upstream levels of I/I, with a
specific proposal including the use of new strategies and technologies to
reduce I/I in these contributing areas. 
Specifically, for the portion of the regional sewer system operated by
MWRA, the MWRA shall update their existing Sanitary Sewer Overflow

Attachment B
MWRA Advisory Board Comments 
Plan, now renamed Sanitary Sewer Overflow Mitigation Plan, and submit
to EPA and MassDEP within 1 year of the effective date of this Permit,
and begin implementing an effective and updated plan consisting of the
following:

Attachment B
MWRA Advisory Board Comments 
NPDES Permit No. MA0103284 2023 Draft Permit 
Page 37 of 68 
i. Identification of all SSO locations; 
ii. A program for periodic inspection and monitoring of overflows
which occur during wet weather; 
iii. Identification of all SSOs that occur as a result of operational
and maintenance deficiencies (e.g., sewer backups, pump
failures) and a plan for improved operation and maintenance
to prevent recurrences; 
iv. Updated procedures for notification of potentially affected
entities (e.g., drinking water suppliers) and the public of
overflows that may endanger human health. 
v. As part of the sewer system operation and maintenance plan
required in I.E.2.e for the portion of the regional sewer system
operated by the MWRA, which shall establish staffing and
operations procedures at MWRA pump stations, headworks
facilities, and at any critical conveyance structures (siphons,
CSO regulators/facilities), which shall encompass the following
goals: 
(a) Maximizing conveyance of wastewater flows to Deer
Island for treatment and discharge; 
(b) Optimizing use of MWRA collection and transport facilities
to manage any capacity restrictions and minimize risk of SSO
impacts to public drinking water supplies, primary contact
resource areas, or other areas where surcharging and/or
overflow conditions will result in serious public health
impacts; and 
(c) At locations where SSO risk is significant, provisions for
preemptive and response actions to mitigate the potential
impacts of the discharge. 
(3) The Draft Permit maintains the requirement for the Permittee, MWRA, to
submit an annual summary report ("Annual Infiltration and Inflow (I/I)
Reduction Report") of all actions taken to reduce I/I during the MWRA's
past fiscal year by September 1st of each year. The Report shall continue
to contain both estimated and actual Community Wastewater Flow
Components Estimates for each of the MWRA member communities
which shall be placed on the MWRA web page for public informational
purposes. The Community Wastewater Flow Components Estimates table
should differentiate between CSO and non-CSO communities. Commented [A1]: Provision seems to summarize a
possible permit requirement but is not written in actual
permit language. As stated in the Advisory Board’s
comments, this provision needs to be re-written and the
public afforded an additional opportunity to comment.

Attachment B
MWRA Advisory Board Comments 
(4) The Draft Permit also requires the Co-permittees to prepare and submit I/I
Reduction Plans. Massachusetts regulations at 314 CMR 12.04 (2)
required municipalities to submit I/I Analysis Reports to MassDEP.

Attachment B
MWRA Advisory Board Comments 
NPDES Permit No. MA0103284 2023 Draft Permit 
Page 38 of 68 
Municipalities were then required to conduct Sewer System Evaluation
Surveys in accordance with their I/I Analysis Report. EPA notes that these
reports can be the basis for I/I Plans to be developed and submitted by the
Co-permittees to remove excessive I/I from the collection system that it
owns and/or operates as required in I.E.2.e below. 
d. Sewer System Mapping 
Within 30 months of the effective date of this Permit, the Permittee, CSO-responsible Co-
permittees and Co-permittees shall prepare a map of the sewer collection system it that each owns
and operates. The map shall be on a street map of the community, with sufficient detail and at a
scale to allow easy interpretation. The sewer system information shown on the map shall be based
on current conditions and shall be kept up-to-date and available for review by federal, state, or
local agencies upon request. Such map(s) shall include, but not be limited to the following: 
1. All sanitary sewer lines and related manholes; 
2. All combined sewer lines, related manholes, and catch basins; 
3. All combined sewer regulators and any known or suspected connections between the
sanitary sewer and storm drain systems (e.g., combination manholes); 
4. All connection points where Co-permittee collection systems connect to the Permittee-
owned collection system or the collection system of another community. 
5. All outfalls, including the treatment plant outfall(s), CSOs, and any known or
suspected SSOs, including stormwater outfalls that are connected to combination
manholes; 
6. All pump stations and force mains; 
7. The wastewater treatment facility(ies); 
8. All surface waters (labeled); 
9. Other major appurtenances such as inverted siphons and air release valves; 
10. A numbering system which uniquely identifies manholes, catch basins,
overflow points, regulators and outfalls; 
11. The scale and a north arrow; and 
12. The pipe diameter, date of installation, type of material, distance between manholes,
and the direction of flow. 
e. Sewer System O&M Plan 
The Permittee, CSO-responsible Co-permittees and Co-permittees shall develop and
implement a Sewer System O&M Plan for the portion of the system it owns and operates. 
Commented [A2]: Provision seems to summarize a
possible permit requirement but is not written in actual
permit language. As stated in the Advisory Board’s
comments, this provision needs to be re-written and the
public afforded an additional opportunity to comment.

Attachment B
MWRA Advisory Board Comments 
(1) Within six (6) months of the effective date of the Permit, the Permittee,
CSO-responsible Co-permittees, and Co-permittees shall each submit to
EPA and the State:

Attachment B
MWRA Advisory Board Comments 
NPDES Permit No. MA0103284 2023 Draft Permit 
Page 39 of 68 
i. A description of the collection system management goals,
staffing, information management, and legal authorities; 
ii. A description of the collection system and the overall
condition of the collection system including a list of all pump
stations and a description of recent studies and construction
activities; and 
iii. A schedule for the development and implementation of the full
Sewer System Operation and Maintenance Plan including the
elements in Parts I.E.2.e.(3)(i) through (3)(ix) below. 
(2) Within 12 months of the effective date of the Permit, the Permittee, CSO-
responsible Co-Permittees and Co-permittees shall develop and
implement a Sewer System Flood Events Plan as an element of the Sewer
System Operations and Maintenance Plan that covers the sewer collection
system that each owns and operates . The Plan shall contain three
components: (1) an asset vulnerability evaluation, (2) a systemic
vulnerability evaluation of the system and (3) an alternatives analysis. The
Plan shall include resiliency planning and implementation informed by an
evaluation 18 of all sewer system vulnerabilities to major storm and flood
events 19 . The planning process shall be iterative, and re-evaluations shall
be conducted; (1) if on- or off-site structures are added, removed or
significantly changed in any way that will impact the vulnerability of the
sewer system and (2) as data sources used for such evaluations are revised
or generated. At a minimum, the Plan must take future conditions into
consideration, specifically midterm (i.e., 20-30 years) and long-term (i.e.,
80-100 years) and, in the case of sea level change, the plan must consider
extreme sea level change. The Plan shall be updated every five (5) years
from the effective date of this Permit. 
18 To determine the vulnerabilities to the facilities from major storm and flood events, you must conduct the
evaluation using, at a minimum, the worst-case data relating to changes in precipitation, sea level rise, extreme
weather events, coastal flooding, inland flooding, sewer flow and inflow and infiltration and relevant to the facilities
from: 1) the data generated by the 13 federal agencies that conduct or use research on global change that contributed
to the latest National Climate Assessment produced by the U.S. Global Change Research Program (USGCRP); 2)
climate data generated by the Commonwealth of Massachusetts; and 3) resiliency planning completed by the
municipality in which a given facility is located (i.e., City of Boston) and incorporate the results of the evaluation in
a manner that demonstrates that the control measures taken are precautionary and sufficiently protective. Evaluation
must be completed by a qualified person on a five-year basis considering: 1) historical observations from all years
the Permittee has operated the facility prior to this Permit’s term; 2) set midterm (i.e., 20-30 years) and long-term
(i.e., 80-100 years) ranges. 
19 “Major storm and flood events” refer to instances resulting from major storms such as hurricanes, extreme/heavy
precipitation events, and pluvial, fluvial, and flash flood events such as high-water events, storm surge, and high-tide
flooding. “Extreme/heavy precipitation” refers to instances during which the amount of rain or snow experienced in a

Attachment B
MWRA Advisory Board Comments 
location substantially exceeds what is normal. What constitutes a period of heavy precipitation varies according to
location and season. “Extreme/heavy precipitation” does not necessarily mean the total amount of precipitation at a
location has increased-just that precipitation is occurring in more intense or more frequent events.

Attachment B
MWRA Advisory Board Comments 
NPDES Permit No. MA0103284 2023 Draft Permit 
Page 40 of 68 
i. Component 1: Asset Vulnerability Evaluation . The first
component of the Sewer System Operation and Maintenance
Plan must assess the vulnerability of individual sewer system-
related assets. The Permittee, CSO-responsible Co-permittees
and Co-permittees may find EPA’s guide: Flood Resilience: A
Basic Guide for Water and Wastewater Utilities 20 and EPA’s
website 21 Creating Resilient Water Utilities (CRWU) helpful
for completing this component. 
The Each Permittee’s, CSO-responsible Co-permittee’s , and Co-
permittee’s Asset Vulnerability Evaluation shall include, at a
minimum, the following: 
(a) Description of planning priorities related to the location of the
sewer system that each owns and operates; 
(b) Identification of all assets (e.g., pump stations, pipes, etc.) that
each owns and operates, the elevation of the asset, and if the asset
falls into the 100-year flood map or the 500-year flood map, 22 
(c) Description of structural improvements, and/or other mitigation
measures 23 to minimize 24 the impacts of major storm and flood
events to each specific asset identified in Part I.E.2.e.(2).i.(b)
above. 
The Permittee, CSO-responsible Co-Permittees, and Co-permittees
shall consider, at a minimum, the following measures: 
(i) Construction of flood barriers to protect structure or
reinforce existing structures to withstand flooding
and additional exertion of force; 
(ii) Establish remote locations for operations, equipment,
records and data backups; 
(iii) Plan and establish alternative or on-site power supply; 25 
20 https://www.epa.gov/sites/default/files/2015-08/documents/flood_resilience_guide.pdf 
21 https://www.epa.gov/crwu 
22 See https://www.epa.gov/sites/default/files/2015-08/documents/flood_resilience_guide.pdf for a basic guide to
flood resiliency for water and wastewater utilities. 
23 Mitigation measure can be an emergency planning activity, equipment modification/upgrade or new capital
investment/construction project. 
24 For the purposes of this provision, the term “minimize” means to reduce and/or eliminate to the extent achievable
the impacts to the facilities.

Attachment B
MWRA Advisory Board Comments 
25 The Permittee shall clearly document measures taken specifically to manage energy system disruptions, such as a
general power outage, well as document whether and, if so, to what extent, power supply adequate to ensure safe and
reliable operations of the facility is threatened during a major storm or flood. They shall clearly document measures
that have been taken to address any risks the facility faces of losing power during a major storm or flood in a manner
that could result in environmental or public health impacts.

Attachment B
MWRA Advisory Board Comments 
NPDES Permit No. MA0103284 2023 Draft Permit 
Page 41 of 68 
(iv) Relocate facilities and/or infrastructure to higher elevations; 
(v) Catalog emergency resources used during a major storm
or flood event; 
(vi) Develop emergency response plans; 
(vii) Establish mutual aid agreements with neighboring utilities; 
(viii) Integrate long-term risks into capital improvement plans; 
(ix) Participate in community planning and
regional collaborations; 
(x) Conduct staff training for implementing your
emergency procedures at regular intervals; 
(xi) When designing new or replacement facilities, strive
to locate facilities above the base flood elevation; 26 
(xii) Identify the source of data used to assess vulnerabilities to
major storm and flood events; and 
(xiii) Identify the potential funding sources 27 for resilience
planning and implementation (e.g., EPA, FEMA,
MassDEP, capital planning, etc.). 
ii. Component 2: Systemic Vulnerability Evaluation. Upon
completing assessment of the vulnerabilities of individual
assets, the Permittee, CSO-responsible Co-permittees, and
Co-permittees shall each evaluate the vulnerability of its the
sewer system that each owns and operates as a whole. This
second component of the plan shall include, at a minimum. a
systematic vulnerability evaluation for each asset identified
in Part I.E.2.e.(2).i.(b), including the following: 
(a) Define the criticality of each asset to the overall sewer
system operations; and 
(b) Identify the highest priority assets for the sewer system and
measures 28 taken to reduce system vulnerability to risks that
could degrade the overall system operations in a manner that
would result in environmental or public health impacts. 
26 For MA facilities, for activities proposed within Areas Subject to Protection under M.G.L. c. 131, § 40 or the 100-
foot buffer zone, the Base Flood Elevation is defined at 310 CMR 10.04, Definitions of Special Flood Hazard Area,
Velocity Zone, and Coastal High Hazard Area, Land Subject to Coastal Storm Flowage at 310 CMR 10.36 and
Bordering Land Subject to Flooding, and Isolated Land Subject to Flooding at 310 CMR 10.57. Also refer to the
Massachusetts State Building Code for any other required standards related to Base Flood Elevation. 
27 See https://www.epa.gov/fedfunds

Attachment B
MWRA Advisory Board Comments 
28 For example, an asset like a pumping station or headworks is often ranked “high” for criticality, as the safe and
reliable operation of many assets during a major storm or flood depend upon the continued operation of that
particular asset. If a pump station is degraded or fails, the operations of many other assets can degrade or fail,
resulting in environmental or public health impacts.

Attachment B
MWRA Advisory Board Comments 
NPDES Permit No. MA0103284 2023 Draft Permit 
Page 42 of 68 
iii. Component 3: Alternatives Evaluation . Upon completing
assessment of the vulnerabilities of the sewer system as a
whole, the Permittee, CSO-responsible Co-Permittees, and Co-
permittees shall each provide an assessment of individual
asset-specific, and/or, if appropriate, combinations of
mitigation measures must be presented in order to determine
the most effective mitigation measures to minimize the impact
of major storm and flood events. 
This third component shall include, at a minimum, the following with regard to
alternative evaluation, at a minimum: 
(a) An evaluation of alternatives including a cost-effectiveness
analysis and a review of technical, environmental, and
institutional factors. The alternatives analysis should
conclude with the development of a recommended plan. 
(b) For each alternative, quantitatively document (including
assumptions and methodologies) the residual risk today and
for the midterm (i.e., 20-30 years) and long-term (i.e., 80-100
years). The evaluation should include estimates of which
customers and geographic areas bear the residual risk from the
approach to resiliency planning in that system. Residual risk is
a term that refers to the risk remaining for an asset or system,
after mitigation measures are taken. 
(c) For each asset, document the total projected alternatives for
implementing all planned mitigation measures identified in
the Sewer System Major Storm and Flood Events Plan. 
(d) Selection of mitigation measures to be undertaken, including: 
(i) a schedule to implement each selected mitigation measure;
and

Attachment B
MWRA Advisory Board Comments 
(ii) a map showing the location of planned mitigation
measures.

Attachment B
MWRA Advisory Board Comments 
NPDES Permit No. MA0103284 2023 Draft Permit 
Page 43 of 68 
iv. Annual Report. The Permittee and each CSO-responsible Co-
permittee and Co-permittee shall submit an Annual Operation
and Maintenance Report on the Sewer System Major Storm and
Flood Events Plan implementation and results for the prior
calendar year including documenting any changes to the sewer
system or other assets that may impact the current vulnerability
evaluation. The first annual report is due the first March 31
following submittal of the Sewer System Major Storm and
Flood Events Plan and shall be included with the annual report
required in Part I.E.3 below. 
(3) The full Sewer System O&M Plan shall be completed, implemented, and
submitted to EPA and to MassDEP within twenty-four (24) months from
the effective date of this Permit. The Plan submitted by each Permittee,
CSO-responsible Co-permittee and Co-permittee shall include: 
i. The required submittal from paragraph I.E.2.e.(1)
above, updated to reflect current information; 
ii. A preventive maintenance and monitoring program for the
collection system; including resiliency evaluation and planning
that the Permittee, CSO-responsible Co-permittees and or Co-
permittees owns and operates; 
iii. Description of sufficient staffing necessary to properly operate
and maintain the sanitary sewer collection system that the
Permittee, CSO-responsible Co-permittees, orand Co-
permittees owns and operates and how the operation and
maintenance program is staffed; 
iv. Description of funding, the source(s) of funding and provisions
for funding sufficient for implementing the plan that the each
Permittee, CSO-responsible Co-permittees, and or Co-
permittees owns and operates planhas developed; 
v. Identification of known and suspected overflows and back-ups,
including manholes, in the sewer system that Permittee, CSO-
responsible Co-permittee, or Co-permittees each owns and
operates. A description of the cause of the identified overflows
and back-ups, corrective actions taken, and a plan for

Attachment B
MWRA Advisory Board Comments 
addressing the overflows and back-ups consistent with the
requirements of this permit that apply to the Permittee, CSO-
responsible Co-permittees, and Co-permittees; 
vi. A description of the Permittee’s, CSO-responsible Co-
permittee’s, or Co-permittee's programs for preventing I/I

Attachment B
MWRA Advisory Board Comments 
NPDES Permit No. MA0103284 2023 Draft Permit 
Page 44 of 68 
related effluent violations and all unauthorized discharges of
wastewater, including overflows and by-passes and the
ongoing program to identify and remove sources of I/I. The
program shall include an inflow identification and control
program that focuses on the disconnection and redirection of
illegal sump pumps and roof down spouts; 
vii. An educational public outreach program for all aspects of I/I
control, particularly private inflow, for the sewer system that
Permittee, CSO-responsible Co-permittees, or Co-permittee
each owns and operates; and 
viii. An Overflow Emergency Response Plan to protect public
health from overflows and unanticipated bypasses or upsets
that exceed any effluent limitation in the Permit applicable
to the sewer system owned and operated, respectively, by
Permittee and each CSO-responsible Co-permittee and Co-
permittee. 
ix. The resiliency evaluation and planning portion of the Sewer
System O&M Plan shall be revised at least every five years.
See Part I.E.2.e.(2). 
3. Annual Reporting Requirement 
The Permittee, CSO-responsible Co-permittees and Co-permittees shall each submit a
summary report of activities related to the implementation of its O&M Plan during the
previous calendar year. The report shall be submitted to EPA and to MassDEP annually
by March 31. The first annual report is due on the first March 31 following submittal of
the O&M Plan required by Part I.E. of this Permit. The summary report shall, at a
minimum, include: 
a. A description of the staffing levels maintained during the year; 
b. A map and a description of inspection and maintenance activities conducted, and
corrective actions taken during the previous year; 
c. Expenditures for any collection system maintenance activities and corrective
actions taken during the previous year; 
d. A map with areas identified for investigation/action in the coming year;

Attachment B
MWRA Advisory Board Comments 
e. A summary of unauthorized discharges during the past year and their causes and
a report of any corrective actions taken as a result of the unauthorized discharges
reported pursuant to the Unauthorized Discharges section of this Permit; and 
f. If the average annual flow in the previous calendar year exceeded 80 percent of the
facility's 361 MGD design flow (288.8 MGD), or there have been capacity related
overflows, the report shall include: 
(4) Plans for further potential flow increases describing how the Permittee
will maintain compliance with the flow limit and all other effluent
limitations and conditions; and

Attachment B
MWRA Advisory Board Comments 
NPDES Permit No. MA0103284 2023 Draft Permit 
Page 45 of 68 
(5) A calculation of the maximum daily, weekly, and monthly infiltration and
the maximum daily, weekly, and monthly inflow for the reporting year. 
g. The Annual Operation and Maintenance Report on the implementation and
results of the WWTF Major Storm and Flood Events Plan (beginning the first
March 31 following submittal of this Plan) for the prior calendar year; and 
h. The Annual Operation and Maintenance Report on the implementation and
results of the Sewer System Major Storm and Flood Events Plan (beginning the
first March 31 following submittal of this Plan) for the prior calendar year. 
F. ALTERNATE POWER SOURCE 
In order to maintain compliance with the terms and conditions of this Permit, the Permittee,
CSO-responsible Co-permittees and Co-permittees shall provide an alternative power
source(s) sufficient to operate the portion of the publicly owned treatment works that each it
owns and operates, as defined in Part II.E.1 of this Permit. 
G. INDUSTRIAL USERS AND PRETREATMENT PROGRAM 
1. The Permittee shall submit to EPA and the State the name of any Industrial User (IU) subject
to Categorical Pretreatment Standards under 40 CFR § 403.6 and 40 CFR chapter I,
subchapter N (Parts 405-415, 417-430, 432, 447, 449-451, 454, 455, 457-461, 463-469, and
471 as amended) who commences discharge to the facility after the effective date of this
permit. 
This reporting requirement also applies to any other IU who is classified as a Significant
Industrial User (SIU) which discharges an average of 25,000 gallons per day or more of
process wastewater into the facility (excluding sanitary, noncontact cooling and boiler
blowdown wastewater); contributes a process wastewater which makes up five (5) percent or
more of the average dry weather hydraulic or organic capacity of the facility; or is designated
as such by the Control Authority as defined in 40 CFR § 403.3(f) on the basis that the
industrial user has a reasonable potential to adversely affect the wastewater treatment
facility’s operation, or for violating any pretreatment standard or requirement (in accordance
with 40 CFR § 403.8(f)(6)). 
2. In the event that the Permittee receives originals of reports (baseline monitoring reports, 90-
day compliance reports, periodic reports on continued compliance, etc.) from industrial users
subject to Categorical Pretreatment Standards under 40 CFR § 403.6 and 40 CFR chapter I,
subchapter N (Parts 405-415, 417-430, 432-447, 449-451, 454, 455, 457-461, 463-469, and 471
as amended), or from a Significant Industrial User, the Permittee shall forward the originals of
these reports within ninety (90) days of their receipt to EPA, and copy the State.

Attachment B
MWRA Advisory Board Comments 
3. In accordance with 40 CFR § 122.44(j)(1) the Permittee must identify, in terms of character
and volume, any SIUs discharging into the POTW or facility subject to Pretreatment
Standards under section 307(b) of CWA and 40 CFR Part 403. SIUs information shall be

Attachment B
MWRA Advisory Board Comments 
NPDES Permit No. MA0103284 2023 Draft Permit 
Page 46 of 68 
updated at a minimum of once per year or at that frequency necessary to ensure that all SIUs
are properly permitted and/or controlled. The records shall be maintained and updated as
necessary. 
4. Beginning the first full calendar year after the effective date of the Permit, the Permittee shall 
commence annual sampling of the following types of industrial discharges into the POTW: 
• Commercial Car Washes 
• Platers/Metal Finishers 
• Paper and Packaging Manufacturers 
• Tanneries and Leather/Fabric/Carpet Treaters 
• Manufacturers of Parts with Polytetrafluoroethylene (PTFE) or teflon type
coatings (i.e., bearings) 
• Landfill Leachate 
• Centralized Waste Treaters 
• Known or Suspected PFAS Contaminated Sites 
• Fire Fighting Training Facilities 
• Airports 
• Any Other Known or Expected Sources of PFAS 
Sampling shall be conducted using Method 1633 for the PFAS analytes listed in Attachment
H . The industrial discharges sampled, and the sampling results shall be summarized and
submitted to EPA and copy the State as an electronic attachment to the March discharge
monitoring report due April 15 of the calendar year following the testing. 
5. Legal Authority 
The Permittee has been delegated primary responsibility for enforcing against
discharges prohibited by 40 CFR § 403.5 and applying and enforcing any national
Pretreatment Standards established by the United States Environmental Protection
Agency in accordance with Section 307 (b) and (c) of The Clean Water Act (Act), as
amended by The Water Quality Act (WQA), of 1987. 
The Permittee shall operate an industrial pretreatment program in accordance with the
General Pretreatment Regulations found in 40 CFR Part 403 and the approved
pretreatment program submitted by the Permittee. The pretreatment program was
approved on July 20, 1982 and has subsequently incorporated substantial modifications
as approved by EPA. The approved pretreatment program, and any approved
modifications thereto, is hereby incorporated by reference and shall be implemented in a
manner consistent with the following procedures, as required by 40 CFR Part 403.

Attachment B
MWRA Advisory Board Comments 
The Permittee must have or develop a legally enforceable municipal code or rules and
regulations to authorize or enable the POTW to apply and enforce the requirements of
Sections 307(b) and (c) and 402(b)(8) and (9) of the Act and comply with the

Attachment B
MWRA Advisory Board Comments 
NPDES Permit No. MA0103284 2023 Draft Permit 
Page 47 of 68 
requirements of § 403.8(f)(1). At a minimum, this legal authority shall enable the POTW
to: 
a. Deny or condition new or increased contributions of pollutants, or changes in the
nature of pollutants, to the POTW by Industrial Users where such contributions do
not meet applicable Pretreatment Standards and Requirements or where such
contributions would cause the POTW to violate its NPDES Permit; 
b. Require compliance with applicable Pretreatment Standards and Requirements by
Industrial Users; 
c. Control through permit, order, or similar means, the contribution to the POTW by
each Industrial User to ensure compliance with applicable Pretreatment Standards
and Requirements. In the case of Industrial Users this control shall be achieved
through permits or equivalent control mechanism identified as significant under 40
CFR § 403.3(v), as required by § 403.8(f)(1)(iii); 
d. Require (a) the development of a compliance schedule by each Industrial User for
the installation of technology required to meet applicable Pretreatment Standards
and Requirements and (b) the submission of all notices and self-monitoring
reports from Industrial Users as are necessary to assess and assure compliance by
Industrial Users with Pretreatment Standards and Requirements, including but not
limited to the reports required in § 403.12; 
e. Carry out all inspection, surveillance and monitoring procedures necessary to
determine, independent of information supplied by Industrial Users, compliance or
noncompliance with applicable Pretreatment Standards and Requirements by
Industrial Users. At a minimum, all significant industrial users shall be sampled
and inspected at the frequency established in the approved IPP, but in no case less
than once per year, and with adequate maintenance of records, Representatives of
the POTW shall be authorized to enter any premises of any Industrial User in
which a Discharge source or treatment system is located or in which records are
required to be kept under § 403.12(o) to assure compliance with Pretreatment
Standards. Such authority shall be at least as extensive as the authority provided
under section 308 of the Act; 
f. Obtain remedies for noncompliance by any Industrial User with any Pretreatment
Standard and Requirement. All POTW's shall be able to seek injunctive relief for
noncompliance by Industrial Users with Pretreatment Standards and
Requirements. All POTWs shall also have authority to seek or assess civil or
criminal penalties in at least the amount of $1,000 a day for each violation by

Attachment B
MWRA Advisory Board Comments 
Industrial Users of Pretreatment Standards and Requirements in accordance with §
403.8(f)(1)(vii)(A); and

Attachment B
MWRA Advisory Board Comments 
NPDES Permit No. MA0103284 2023 Draft Permit 
Page 48 of 68 
g. Comply with the confidentiality requirements set forth in § 403.14.
6. Implementation Requirements 
The Permittee shall operate a pretreatment program in accordance with the General
Pretreatment Regulations found in 40 CFR Part 403 and with the legal authorities,
policies, procedures, and financial provisions of the approved Pretreatment program
submitted by the Permittee. The approved Pretreatment program, and any approved
modifications thereto, is hereby incorporated by reference and shall be implemented in a
manner consistent with the following procedures, as required by 40 CFR Part 403: 
a. In accordance with 40 CFR § 122.44(j)(1), Identify, in terms of character and
volume of pollutants contributed from Industrial Users discharging into the
POTW subject to Pretreatment Standards under section 307(b) of CWA and 40
CFR Part 403. 
b. The Permittee must notify these identified Industrial Users of applicable
Pretreatment Standards and any applicable requirements in accordance with 40
CFR § 403.8(f)(2)(iii). Pursuant to 40 CFR § 403.8(f)(6), prepare and maintain a
list of significant industrial users and identify the criteria in 40 CFR §
403.3(v)(1) applicable to each industrial user. 
c. The Permittee must carry out inspection procedures and randomly sample and
analyze the effluent from Industrial Users and conduct surveillance activities in
accordance with 40 CFR § 403.8(f)(2)(v), which will determine independent of
information supplied by the industrial user, whether the industrial user is in
compliance with the Pretreatment Standards. At a minimum, all significant
industrial users shall be sampled and inspected at the frequency established in the
approved IPP but in no case less than once per year and maintain adequate records. 
d. The Permittee shall receive and analyze self-monitoring reports and other notices
submitted by Industrial Users in accordance with the self-monitoring requirements
in 40 CFR § 403.12; This must include timely and appropriate reviews of industrial
user reports and notifications to identify all violations of the user's permit, the local
ordinance, and federal pretreatment standards and requirements. 
e. The Permittee shall evaluate whether each SIU needs a plan to control Slug
Discharges in accordance with 40 CFR § 403.8(f)(2)(vi). SIUs must be evaluated
within 1 year of being designated an SIU. If required, the Permittee shall require
the SIU to prepare or update and implement a slug prevention plan that contains at
least the minimum required elements in 40 CFR § 403.8(f)(2)(vi)(A-D) and
incorporate the slug control requirements into the SIU’s control mechanism.

Attachment B
MWRA Advisory Board Comments 
f. Pursuant to 40 CFR § 403.8(f)(2)(vii), the Permittee shall investigate instances
of non-compliance with Pretreatment Standards and requirements indicated in

Attachment B
MWRA Advisory Board Comments 
NPDES Permit No. MA0103284 2023 Draft Permit 
Page 49 of 68 
required reports and notices or indicated by analysis, inspection, and surveillance
activities. 
g. The Permittee shall publish, at least annually, in a newspaper or newspapers of
general circulation that provides meaningful public notice within the jurisdiction(s)
served by the POTW, a list of all non-domestic users which, at any time in the
previous 12 months, were in significant noncompliance as defined in 40 CFR §
403.8 (f)(2)(viii). 
h. The Permittee shall provide sufficient resources and qualified personnel to
implement its Pretreatment program in accordance with 40 CFR § 403.8(f)(3); 
i. The Permittee shall enforce all applicable Pretreatment Standards and requirements
and obtain remedies for noncompliance by any industrial user. The Permittee shall
develop, implement, and maintain an enforcement response plan in accordance
with 40 CFR § 403.8(f)(5). 
j. Pursuant to 40 CFR § 403.8(g), the Permittee that chooses to receive electronic

The text goes on. The rest is in the file.