(Slip Opinion)

OCTOBER  TERM,  2024

1

Syllabus

NOTE:  Where  it  is  feasible,  a  syllabus  (headnote)  will  be  released,  as  is
being  done  in  connection  with  this  case,  at  the  time  the  opinion  is  issued.
The  syllabus  constitutes  no  part  of  the  opinion  of  the  Court  but  has  been
prepared  by  the  Reporter  of  Decisions  for  the  convenience  of  the  reader.
See United States v. Detroit Timber & Lumber Co., 200 U. S. 321, 337.

SUPREME COURT OF THE UNITED STATES

Syllabus

CITY AND COUNTY OF SAN FRANCISCO,
CALIFORNIA v. ENVIRONMENTAL PROTECTION
AGENCY

CERTIORARI TO THE UNITED STATES COURT OF APPEALS FOR
THE NINTH CIRCUIT

No. 23–753.  Argued October 16, 2024—Decided March 4, 2025

Under the Clean Water Act (CWA), 33 U. S. C. §1151 et seq., the Envi-
ronmental Protection Agency (EPA) and authorized state agencies is-
sue  permits  that  impose  requirements  on  entities  that  wish  to  dis-
charge  “pollutants”  into  the  waters  of  the  United  States.    A  critical
component  of  the  CWA  regulatory  scheme  is  the  National  Pollutant
Discharge Elimination System (NPDES), which makes it unlawful to
discharge pollutants into covered bodies of water unless authorized by
permit. EPA  v.  California ex  rel.  State  Water  Resources Control  Bd.,
426 U. S. 200, 205.  These permits typically include “effluent limita-
tions” on discharges that restrict the “quantities, rates, and concentra-
tions  of  chemical,  physical,  biological,  and  other  constituents.”
§1362(11).   Failure to comply with permit limitations exposes permit-
tees  to  civil  penalties  and  even  criminal  prosecution.    §§1319(c)  and
(d).  Under what is known as the “permit shield” provision, however,
an entity that adheres to the terms of its permit is deemed to be com-
pliant with the Act. §1342(k).

This case involves a challenge to “end-result” requirements—permit
provisions that do not spell out what a permittee must do or refrain
from doing but instead make a permittee responsible for the quality of
the  water  in  the  body  of  water  into  which  the  permittee  discharges
pollutants.  The  City  of  San  Francisco  operates  two  combined
wastewater  treatment  facilities  that  process  both  wastewater  and
stormwater.  Combined Sewer Overflow (CSO) Control Policy, 59 Fed.
Reg. 18689; 75 F. 4th 1074, 1082 (CA9).  During periods of heavy pre-
cipitation, the combination of wastewater and stormwater may exceed
the facility’s capacity, and the result may be the discharge of untreated

2

CITY AND COUNTY OF SAN FRANCISCO v. EPA

Syllabus

water, including raw sewage, into the Pacific Ocean or the San Fran-
cisco Bay. 59 Fed. Reg. 18689; EPA, Office of Water, Combined Sewer
Overflows:  Guidance  for  Permit  Writers,  p.  1–1;  75  F.  4th,  at  1082–
1083.  In 1994, the EPA adopted its CSO Control Policy, which requires
municipalities  with  combined  systems  to  take  prescribed  measures
and to develop and implement a Long-Term Control Plan, and provides
for a two-phase permitting process.  59 Fed. Reg. 18691, 18696.

For  many  years,  San  Francisco’s  NPDES  permit  for  its  Oceanside
facility was renewed without controversy, but in 2019, the EPA issued
a renewal permit that added two end-result requirements. 75 F. 4th,
at 1084–1085.  The first of these prohibits the facility from making any
discharge  that  “contribute  to  a  violation  of  any  applicable  water
quality standard” for receiving waters.  Id., at 1085.  The second pro-
vides  that  the  City  cannot  perform  any  treatment  or  make  any  dis-
charge that “create pollution, contamination, or nuisance as defined
by  California  Water  Code  section  13050.”  Ibid.  (internal  quotation
marks  omitted).    San  Francisco  argued  that  the  end-result  require-
ments exceed EPA’s statutory authority, but the Ninth Circuit denied
the city’s petition for review.  The court held that §1311(b)(1)(C) au-
thorizes  EPA  to  impose  “any”  limitations  ensuring  applicable  water
quality standards are satisfied in a receiving body of water.

Held: Section 1311(b)(1)(C) does not authorize the EPA to include “end-
result” provisions in NPDES permits.  Determining what steps a per-
mittee must take to ensure that water quality standards are met is the
EPA’s  responsibility,  and  Congress  has  given  it  the  tools  needed  to
make that determination.  Pp. 7–19.

(a) Not all “limitations” under §1311 must qualify as effluent limita-
tions.    While  §§1311(b)(1)(A)  and  (B)  refer  to  “effluent  limitations,”
§1311(b)(1)(C) refers to “any more stringent limitation.”  This distinc-
tion shows that Congress intentionally authorized limitations beyond
effluent  limitations  because  “it  is  generally  presumed  that  Congress
acts  intentionally  and  purposely  in  the  disparate  inclusion  or  exclu-
sion” of language in a statute.  Russello v. United States, 464 U. S. 16,
23 (internal quotation marks omitted).  Other CWA provisions support
this by referring to “effluent limitations and other limitations” under
§1311.  See, e.g., §§1341(d), 1365(f).  Moreover, San Francisco’s inter-
pretation  would  either  invalidate  widely  accepted  narrative  permit
provisions or require an improbably broad reading of “effluent limita-
tion.”  Pp. 7–9.

(b) Section  1311(b)(1)(C)  does  not  authorize  permit  requirements
conditioning  compliance  on  receiving  water  quality.  The  provision’s
text, structure, and context support this interpretation.  Pp. 9–19.
“meet”

in
§1311(b)(1)(C)  suggest  EPA  must  set  specific  rules  permittees  must

“implement,”  and

“limitation,”

(1) The

terms

Cite as:  604 U. S. ____ (2025)

3

Syllabus

follow to achieve water quality goals.  A “limitation” is a “restriction
. . . imposed from without,” not an end-result requirement leaving per-
mittees to determine necessary steps.  Webster’s Third New Interna-
tional Dictionary 1312.  When a provision tells a permittee that a par-
ticular end result must be achieved, the direct source of the restriction
comes from within, not “from without.”  To “implement” standards re-
quires “concrete measures,” not simply mandating achievement of re-
sults.  Id., at 1134; §1311(b)(1)(C).  A limitation that is “necessary to
meet” an objective is most naturally understood to mean a provision
that sets out actions that must be taken to achieve the objective.  Pp.
10–12.

(2)  The pre-1972 Water Pollution Control Act (WPCA) contained
a  provision  that  allowed  direct  enforcement  against  a  polluter  if  the
quality  of  the  water  into  which  the  polluter  discharges  pollutants
failed to meet water quality standards.  See Federal Water Pollution
Control Act, ch. 758, §§1, 2(d)(1), 2(d)(4), 2(d)(7), 62 Stat. 1155, 1156–
1157.  But Congress deliberately omitted such provisions when over-
hauling  the  law  in  1972.    Instead,  the  CWA  imposes  “direct  re-
strictions” on polluters rather than working backward from pollution
to  assign  responsibility.  EPA,  426  U. S.,  at  204.    The  Government’s
interpretation  would  undo  what  Congress  plainly  sought  to  achieve
when it scrapped the WPCA’s backward-looking approach.  Pp. 12–14.
(3) Two features of the broader statutory scheme further support
this  conclusion.    First,  end-result  requirements  would  negate  the
CWA’s “permit shield” protecting compliant permittees from liability.
Second, EPA’s interpretation provides no mechanism for fairly allocat-
ing  responsibility  among  multiple  dischargers  contributing  to  water
quality violations.  Pp. 14–16.

(c) The agency has adequate tools to obtain needed information from
permittees without resorting to end-result requirements.  Its reliance
on  the  Combined  Sewer  Overflow  Policy  is  misplaced  as  that  policy
authorizes narrative limitations but not end-result requirements.  And
concerns about disrupting general permits are unfounded given that
narrative limitations remain available.  Pp. 17–19.

75 F. 4th 1074, reversed and remanded.

ALITO, J., delivered the opinion of the Court, in which ROBERTS, C. J.,
and THOMAS and KAVANAUGH, JJ., joined, in which GORSUCH, J., joined
as  to  all  but  Part  II,  and  in  which  SOTOMAYOR,  KAGAN,  BARRETT,  and
JACKSON, JJ., joined as to Part II.  BARRETT, J., filed an opinion dissent-
ing in part, in which SOTOMAYOR, KAGAN, and JACKSON, JJ., joined.

Cite as:  604 U. S. ____ (2025)

1

Opinion of the Court

NOTICE: This opinion is subject to formal revision before publication in the
United  States  Reports.  Readers  are  requested  to  notify  the  Reporter  of
Decisions,  Supreme  Court  of  the  United  States,  Washington,  D. C.  20543,
pio@supremecourt.gov, of any typographical or other formal errors.

SUPREME COURT OF THE UNITED STATES

_________________

No. 23–753
_________________

CITY AND COUNTY OF SAN FRANCISCO,
CALIFORNIA, PETITIONER v. ENVIRON-
MENTAL PROTECTION AGENCY

ON WRIT OF CERTIORARI TO THE UNITED STATES COURT OF
APPEALS FOR THE NINTH CIRCUIT



JUSTICE ALITO delivered the opinion of the Court.
Under  the  Clean  Water  Act  (CWA),  86  Stat.  816,  33
U. S. C. §1251 et seq., the Environmental Protection Agency
(EPA)  and  authorized  state  agencies1  may  issue  permits
that impose requirements on entities that wish to discharge
“pollutants” (a broadly defined term) 2 into the waters of the
United States.3  Permits issued by these agencies include
what  the  CWA  calls  “effluent  limitations,”  that  is,  provi-
sions that specify the quantities of enumerated pollutants
that may be discharged.4  It is also common for permits to
set out other steps that a discharger must take.  These may
include  testing,  record-keeping,  and  reporting  require-
ments,  as  well  as  requirements  obligating  a  permittee  to
follow  specified  practices  designed  to  reduce  pollution.

——————

1 See  33  U. S. C.  §1342(b).    The  provision  at  issue  in  this  case,
§1311(b)(1)(C), applies equally to federal and state permits, but for con-
venience, we refer only to the EPA when referring to the scope of permit-
ting authority under that provision.

2 §1362(6).
3 §1362(7).
4 §1362(11).

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CITY AND COUNTY OF SAN FRANCISCO v. EPA

Opinion of the Court

None of these so-called narrative requirements is at issue
here.

Instead, this case involves provisions that do not spell out
what  a  permittee  must  do  or  refrain  from  doing;  rather,
they make a permittee responsible for the quality of the wa-
ter in the body of water into which the permittee discharges
pollutants.  When a permit contains such requirements, a
permittee that punctiliously follows every specific require-
ment in its permit may nevertheless face crushing penalties
if the quality of the water in its receiving waters falls below
the applicable standards.  For convenience, we will call such
provisions “end-result” requirements.

The permittee in this case is a wastewater treatment fa-
cility owned by San Francisco.  For the past five years, the
facility’s permit has included two end-result requirements,
and if those provisions are upheld, the City could be heavily
penalized even though it was never put on notice that it was
obligated to take any specific step other than those it un-
dertook.    San  Francisco  argues  that  the  end-result  provi-
sions in its permit are not authorized by the CWA, and its
position is supported by many other similarly situated cit-
ies, including New York, the District of Columbia, Boston,
and  Buffalo,  as  well  as  national  and  state  associations
whose  members  collectively  “provide  wastewater  and
stormwater  services  to  the  majority  of  .” 5

We  hold  that  the  two  challenged  provisions  exceed  the
EPA’s  authority.    The  text  and  structure  of  the  CWA,  as
well  as  the  history  of  federal  water  pollution  legislation,
make this clear.  And resorting to such requirements is not
necessary to protect water quality.  The EPA may itself de-
termine what a facility should do to protect water quality,

——————

5 Brief for Public Wastewater and Stormwater Agencies et al. as Amici

Curiae 2.

Cite as:  604 U. S. ____ (2025)

3

Opinion of the Court

and the Agency has ample tools to obtain whatever infor-
mation  it  needs  to  make  that  determination.   If  the  EPA
does its work, our holding should have no adverse effect on
water quality.

I
A

To understand the issue before us, it is helpful to take a
brief look back at the history of federal water pollution leg-
islation.  For most of the Nation’s history, the Federal Gov-
ernment played a secondary role in this field.  See Sackett
v. EPA, 598 U. S. 651, 659 (2023).  In 1948, however, Con-
gress  passed  the  Federal  Water  Pollution  Control  Act
(WPCA), ch. 758, 62 Stat. 1155, which represented a cau-
tious expansion of federal authority.  K. Murchison, Learn-
ing  From  More  Than  Five-and-a-Half  Decades  of  Federal
Water  Pollution  Control  Legislation:  Twenty  Lessons  for
the  Future,  32  Env.  Affairs  L. Rev.  527,  530–531  (2005)
The  WPCA  reaffirmed  the  long-accepted  principle  that
“controlling water pollution” was primarily a state respon-
sibility, but it also declared that the pollution of certain in-
terstate  waters  had  become  “a  public  nuisance”  and  was
“subject  to  abatement  in  a  suit”  brought  by  the  Attorney
General on behalf of the United States.  §§1, 2(d)(1), 2(d)(4),
2(d)(7), 62 Stat. 1155–1157.

Over the next 24 years, the WPCA was amended numer-
ous  times,6  and  the  federal  role  gradually  grew,  but  the
basic structure of federal enforcement actions remained the
same.  The starting point was the identification of a body of
water with substandard water quality.  After that, federal

——————

6 See  Water  Pollution  Control  Act  Amendments  of  1956,  Pub.  L.  84–
660, 70 Stat. 498; Federal Water Pollution Control Act Amendments of
1961, Pub. L. 87–88, 75 Stat. 204; Water Quality Act of 1965, Pub. L. 89–
234, 79 Stat. 903; Water Quality Improvement Act of 1970, Pub. L. 91–
224, 84 Stat. 91.

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CITY AND COUNTY OF SAN FRANCISCO v. EPA

Opinion of the Court

authorities had to work backward and prove that a partic-
ular  entity  should  be  held  responsible  for  the  problem.7
Both  the  original  version  of  the  1948  Act  and  all  amend-
ments enacted before 1972 proved to be ineffective due in
part to this backward-looking model.  See EPA v. California
ex rel. State Water Resources Control Bd., 426 U. S. 200, 202
(1976).

By 1972, the WPCA’s inadequacy was apparent, and Con-
gress made a fresh start.  It amended the WPCA by deleting
all  its  provisions  and  substituting  what  is  now  generally
known  as  the  Clean  Water  Act.  The  CWA  jettisoned  the
WPCA’s  retrospective  approach  and  aimed  directly  at  the
sources  of  pollution.  A  critical  component  of  the  CWA
scheme  is  the  National  Pollutant  Discharge  Elimination
System (NPDES), see id., at 204–205, which makes it un-
lawful to discharge pollutants into covered bodies of water
unless  authorized  by  permit.    Permits  issued  under  this
program may contain several different types of provisions.
Some are known as “effluent limitations,” see 33 U. S. C.
§1311, which are defined as restrictions on the “quantities,
rates, and concentrations of chemical, physical, biological,
and  other  constituents.”  §1362(11).    Section  1311(b)(1),
subparagraphs  (A)  and  (B)  require  compliance  with  one
type  of  effluent  limitations:  those  that  are  based  on  what
can  be  achieved  using  specified  pollution-treatment  tech-
nologies.  See 40 CFR §122.44(a)(1) (2023).  In most cases,
these technology-based limitations are sufficient, but when
they  are  not,  NPDES  permits  also  include  water  quality-
33  U. S. C.
based  effluent
§1311(b)(1)(C).  These  WQBELs,  unlike  technology-based
effluent limitations, are “set without regard to cost or tech-
nology availability.”  Natural Resources Defense Council v.
EPA, 808 F. 3d 556, 565 (CA2 2015); see Natural Resources

(WQBELs).

limitations

——————

7 See §2(d), 62 Stat. 1156–1157; 70 Stat. 504–505; 75 Stat. 208–209; 79

Stat. 909.

Cite as:  604 U. S. ____ (2025)

5

Opinion of the Court

Defense  Council,  Inc.  v.  EPA, 859  F. 2d  156,  208  (CADC
1988)  (per curiam).  Instead,  they  permit  only  those  dis-
charges that may be made without unduly impairing water
quality.

In addition to these effluent limitations, it is common for
permits to include requirements that do not set numerical
limitations on allowed discharges.  One example, which is
apparently common in so-called general permits, is a provi-
sion demanding that permittees follow certain “best prac-
tices” that aim to limit pollution.8

Under the NPDES system, permittees have a very strong
incentive to comply with all permit terms.  For one thing,
the CWA gives the EPA a very big “stick.”  Permittees that
do not comply may be hit with enormous civil penalties and
may face criminal prosecution for “knowing” or even “negli-
gent”  violations.    See  §§1319(c)  and  (d);  40  CFR  §19.4
(2023).  At the same time, the CWA holds out an enticing
“carrot.”  Under what is known as the “permit shield” pro-
vision, an entity that adheres to the terms of its permit is
deemed  to  be  compliant  with  the  Act.  See  33  U. S. C.
§1342(k).

B
The case now before us involves a particular type of pub-
lic  wastewater  treatment,  one  that  processes  both
wastewater  (water  that  has  been  used  in  a  home)  and
stormwater (rainwater that does not sink into the ground).
Many major cities have such systems, and they present spe-
cial  problems.  During  periods  of  heavy  precipitation,  the
combination of wastewater and stormwater may exceed the
facility’s treatment capacity, and the result may be the dis-
charge of untreated water, including raw sewage.  See Com-
bined  Sewer  Overflow  (CSO)  Control  Policy,  59  Fed.  Reg.

——————

8 See Brief for National Association of Home Builders et al. as Amici

Curiae 1, 11–12.

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CITY AND COUNTY OF SAN FRANCISCO v. EPA

Opinion of the Court

18689 (1994); EPA, Office of Water, Combined Sewer Over-
flows:  Guidance  for  Permit  Writers,  p. 1–1  (1995).    This
problematic  feature  of  combined  facilities  was  recognized
long ago; installing a new system that handles stormwater
and wastewater separately is enormously expensive.9

To  address  the  problem  of  CSOs,  the  EPA  adopted  its
CSO  Control  Policy,  which  requires  municipalities  with
combined systems to take prescribed measures and to de-
velop and implement a Long-Term Control Plan.  59 Fed.
Reg. 18691.  The CSO Policy provides for a two-phase per-
mitting process.  Id., at 18696.  During phase I, permits re-
quire municipalities to implement nine minimum controls
and  to  develop  a  long-term  plan.    Then,  during  phase  II,
that plan must be implemented.  Ibid.  In 2000, Congress
amended  the  CWA  and  gave  the  CSO  Control  Policy  the
force of a statute.  See 33 U. S. C. §1342(q)(1).

C
The  city  of  San  Francisco  operates  two  combined  treat-
ment facilities: the Bayside facility, which discharges into
San Francisco Bay, and the Oceanside facility, which emp-
ties into the Pacific Ocean.  The permit at issue in this dis-
pute  concerns  only  the  Oceanside  facility,10  which  treats
water from 250 miles of sewers and serves approximately
250,000 residents.  75 F. 4th 1074, 1082 (CA9 2023).

For many years, the Oceanside facility’s NPDES permit
was renewed without controversy, but in 2019, the two end-
result  requirements  that  San  Francisco  now  challenges
were added.  Id., at 1084–1085.  The first of these prohibits
the facility from making any discharge that “contribute
to a violation of any applicable water quality standard” for
receiving  waters.  Id.,  at  1085.  The  second  provides  that

——————

9 T. Camp, The Problem of Separation in Planning Sewer Systems, 38

J. Water Pollution Control Federation 1959 (1966).

10 See App. to Pet. for Cert. 80–140.

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7

Opinion of the Court

the  City  cannot  perform  any  treatment  or  make  any  dis-
charge that “create pollution, contamination, or nuisance
as defined by California Water Code section 13050.”  Ibid.
(internal quotation marks omitted).

in

The California Regional Water Quality Control Board for
the San Francisco Bay Region approved the final Oceanside
NPDES permit, and the EPA did the same.11  Id., at 1088.
San  Francisco  appealed  to  the  EPA’s  Environmental  Ap-
peals  Board  (EAB),  objecting  to,  among  other  things,  the
two new provisions just noted.  City and Cty. of San Fran-
cisco,  18  E. A. D.  322,  325  (2020).    The  EAB  rejected  San
Francisco’s challenge, and the City then filed a petition for
review
the  Ninth  Circuit  under  33  U. S. C.
§1369(b)(1)(F).  75 F. 4th, at 1088.  A divided Ninth Circuit
panel denied that petition, holding that §1311(b)(1)(C) au-
thorizes the EPA to impose “any” limitations that seek to
ensure that applicable water quality standards are satisfied
in a receiving body of water.  Id., at 1089–1090.  In dissent,
Judge Collins argued that the CWA “draws an explicit dis-
tinction between the ‘limitations’ that the agency must de-
vise and impose on a particular permittee’s discharges” and
the water quality standards themselves.  Id., at 1102 (Col-
lins, J., dissenting).  The majority, he maintained, erred by
making the “ ‘water quality standards’ themselves the ap-
plicable ‘limitation’ for an individual discharger.”  Ibid.

We granted certiorari to decide whether the EPA can im-
pose requirements like those at issue.  602 U. S. ___ (2024).

II

Contending

the  Ninth  Circuit  misread
§1311(b)(1)(C), San Francisco leads with the argument that

that

——————

11 Both the California Regional Water Quality Control Board and the
EPA had to approve the NPDES permit because the Oceanside facility
discharges into waters that fall under both state and federal jurisdiction.
75 F. 4th 1074, 1082 (CA9 2023) (case below).

8

CITY AND COUNTY OF SAN FRANCISCO v. EPA

Opinion of the Court

all “limitations” imposed under §1311 must qualify as efflu-
ent limitations.  The statutory text dooms this broad argu-
ment.  “here Congress includes particular language in
one section of a statute but omits it in another section of the
same Act, it is generally presumed that Congress acts in-
tentionally and purposely in the disparate inclusion or ex-
clusion.”  Russello v. United States, 464 U. S. 16, 23 (1983)
(internal quotation marks omitted).  We have invoked this
canon time and time again.  See, e.g., Gallardo v. Marstiller,
596 U. S. 420, 429–430 (2022); Salinas v. Railroad Retire-
ment Bd., 592 U. S. 188, 196 (2021); Azar v. Allina Health
Services, 587 U. S. 566, 576–577 (2019).  And it is fatal to
San Francisco’s argument here.  Sections 1311(b)(1)(A) and
(B) refer to “effluent limitations,” but the very next provi-
sion, §1311(b)(1)(C), refers instead to “any more stringent
limitation.”  We cannot believe that Congress omitted the
term  “effluent”  from  §1311(b)(1)(C)  simply  because  it
wanted to save ink or assumed that regulators and inter-
ested  parties  would  understand  that  the  omission  of  the
term was inconsequential.

Other provisions of the CWA support this conclusion by
describing §1311 as authorizing the EPA to impose effluent
or  other  limitations.    See  §1341(d)  (referring  to  “effluent
limitations  and  other  limitations,  under  section  1311”);
§1365(f ) (referring to “effluent limitation or other limita-
tion under section 1311”); §1367(d) (same); see also Na-
tional  Assn.  of  Mfrs.  v.  Department  of  Defense,  583  U. S.
109, 122 (2018) (interpreting the phrase “effluent limitation
or other limitation” in the CWA’s judicial review provision,
§1369, to encompass both “effluent” limitations and limita-
tions  such  as  “non-numerical  operational  practice”  and
“equipment specification”).

These reasons convince us that San Francisco’s argument
is  wrong,  but  if  more  were  needed,  it  is  telling  that  the
City’s  interpretation  would  lead  to  either  drastic  conse-
quences that the City is unwilling to embrace or a very loose

Cite as:  604 U. S. ____ (2025)

9

Opinion of the Court

interpretation of the term “effluent limitation” that would
undermine the City’s argument.  As noted earlier, it is com-
mon for permits to contain “narrative” provisions requiring
permittees to do such things as following certain “best prac-
tices.”  These provisions do not directly restrict the “quan-
tities, rates, or concentration” of pollutants that a permittee
may discharge, and therefore they do not fit easily within
the definition of an “effluent limitation.”  Nevertheless, the
City acknowledges their legitimacy, see Brief for Petitioner
15, 33, n. 22, and if that is correct, it must follow either that
(1)  §1311(b)(1)(C)  authorizes  the  imposition  of  limitations
other than effluent limitations (which would, of course, de-
feat the City’s argument) or (2) the statutory definition of
an  effluent  limitation  should  be  read  very  loosely  (which
raises the question why this broad interpretation would not
encompass the provisions at issue here).  Under either al-
ternative, the City is on perilous ground.

These problems overwhelm any help that the City can de-
rive from the fact that §1311 is titled “Effluent limitations.”
The title of a statutory provision can inform its interpreta-
tion, but it is not conclusive.  See Dubin v. United States,
599 U. S. 110, 120–121 (2023).  And here, the title of §1311
is not enough to win the day for the City.  Section 1311 is a
lengthy provision, and most of its subsections concern efflu-
ent limitations.  The title “Effluent limitations” provides a
rough  description  of  the  provision’s  general  sweep,  but  it
cannot be read as doing more than that.

III
In addition to the broad argument discussed above, San
Francisco  advances  a  narrower  alternative,  namely,  that
even if §1311(b)(1)(C) is not limited to effluent limitations,
it  “does  not  authorize  EPA  to  impose  NPDES  permit  re-
quirements  that  condition  permitholders’  compliance  on
whether  receiving  waters  meet  applicable  water  quality

10

CITY AND COUNTY OF SAN FRANCISCO v. EPA

Opinion of the Court

standards.”  Brief for Petitioner 19.  We agree with this ar-
gument.  As the City maintains, “he text, structure, and
pre-  and  post-enactment  context”  support  this  interpreta-
tion.  Ibid.

A
We begin with the text of §1311(b)(1)(C), which, as noted,
requires a permit to contain, in addition to “effluent limita-
tions,” “any more stringent limitation” that is “necessary to
meet”  certain  “water  quality  standards”  that  are  imposed
under  state  law  “or  any  other  federal  law  or  regulation”;
and “any more stringent limitation” that is “required to im-
plement any applicable water quality standard established
pursuant to this chapter.”  (Emphasis added.)  All the itali-
cized terms in the preceding sentence suggest that the most
natural reading of §1311(b)(1)(C)  is that it authorizes the
EPA  to  set rules  that a  permittee  must  follow  in  order to
achieve a desired result, namely, a certain degree of water
quality.

We start with the term “limitation.”  As used in the rele-
vant context, a limitation is a “restriction or restraint im-
posed from without (as by law.”  Webster’s Third New In-
ternational  Dictionary  1312  (1976)  (emphasis  added).  A
provision that tells a permittee that it must do certain spe-
cific things plainly qualifies as a limitation.  Such a provi-
sion imposes a restriction “from without.”  But when a pro-
vision simply tells a permittee that a particular end result
must be achieved and that it is up to the permittee to figure
out what it should do, the direct source of restriction or re-
straint is the plan that the permittee imposes on itself for
the purpose of avoiding future liability.  In other words, the
direct source of the restriction comes from within, not “from
without.”

We do not dispute that the term “limitation” is sometimes
used in a looser sense, but our task is to ascertain what the
term means in the specific context in question.  And here,

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11

Opinion of the Court

our interpretation of the meaning of the term “limitation”
in §1311(b)(1)(C) must take into account the way in which
the term is used in the two preceding statutory subsections,
§§1311(b)(1)(A) and (B).  In both those provisions, the “lim-
itations” are imposed directly by the EPA, and it is there-
fore natural to presume that the term has a similar mean-
ing in §1311(b)(1)(C).  See, e.g., McDonnell v. United States,
579 U. S. 550, 568–569 (2016); Yates v. United States, 574
U. S. 528, 544 (2015) (plurality opinion); A. Scalia & B. Gar-
ner, Reading Law 195–198 (2012).  So the use of the term
“limitation” in §§1311(b)(1)(A) and (B) provides an opening
clue that the EPA’s interpretation of §1311(b)(1)(C) may be
wrong.

The terms “implement” and “meet” point in the same di-
rection.  The implementation of an objective generally re-
fers to the taking of actions that are designed “to give prac-
tical effect  to and ensure of actual fulfillment by concrete
measures.”  Webster’s Third New International Dictionary,
at 1134.  Section 1311(b)(1)(C) tells the EPA to impose re-
quirements to “implement” water quality standards—that
is,  to  “ensure”  “by  concrete  measures”  that  they  are  “ac-
tual” “fulfill.”  Simply telling a permittee to ensure
that  the  end  result  is reached  is  not  a  “concrete  plan”  for
achieving the desired result.  Such a directive simply states
the desired result; it does not implement that result.

Section 1311(b)(1)(C)’s other directive—that the EPA im-
pose limitations that are “necessary to meet” certain water
quality  standards–is  similar.  The  verb  to  “meet,”  in  the
sense operative here, means “to comply with; fulfill; satisfy”
or  “to  come  into  conformity  with.”    Random  House  Una-
bridged Dictionary 1195 (2d ed. 1987).  Thus, a limitation
that  is  “necessary  to  meet”  an  objective  is  most  naturally
understood to mean a provision that sets out actions that
must be taken to achieve the objective.

In assessing what the directives in §1131(b)(1)(C) mean,

12

CITY AND COUNTY OF SAN FRANCISCO v. EPA

Opinion of the Court

it is helpful to consider the use of the relevant terms in eve-
ryday  speech.    Suppose  a  State  requires  that  all  schools
“meet” certain standards of math proficiency, and suppose
the  principal  of  a  school  calls  a  faculty  meeting  and  in-
structs the teachers to “implement” those standards.  The
principal’s obvious expectation would be that the teachers
would devise and “implement” a plan to make sure that the
desired end is “met.”  It is unlikely that the principal would
be happy if the teachers simply told their students that a
state math proficiency test would be administered and that
they should make sure they passed.  That would not consti-
tute the implementation of the desired end, i.e., meeting the
State’s standard of math proficiency.

Attempting  to  counter  this  interpretation,  the  EPA
stresses §1311(b)(1)(C)’s use of the term “any” in the phrase
“any more stringent limitation,” arguing that “any” is a very
broad term.  That argument misconstrues the term’s effect.
The  adjective  “any”  is  indeed  a  broad  term,  but  it  cannot
expand  the  reach  of  the  noun  it  modifies.    A  reference  to
“any  mammal”  would  capture  all  mammals,  but  it  would
not encompass a bird or fish.  Similarly, §1311(b)(1)(C) en-
compasses any limitation that is necessary to meet or im-
plement water quality standards, but not provisions that do
not fall within that category.

B
The text of the CWA militates against the Government’s
interpretation of §1311(b)(1)(C) for yet another reason that
stands out when the history of federal water pollution con-
trol  legislation  is  kept  in  mind.    Under  the  Government’s
reading, a permittee may be held liable if the quality of the
water into which it discharges pollutants fails to meet wa-
ter quality standards.  Before 1972, the WPCA contained a
provision that did exactly that in no uncertain terms.  But
when Congress overhauled the WPCA in 1972, it scrapped
that provision and did not include in the new version of the

Cite as:  604 U. S. ____ (2025)

13

Opinion of the Court

Act anything remotely similar.  Under these circumstances,
the absence of a comparable provision in the CWA is telling.
This glaring void resulted from a deliberate and promi-
nent policy  choice.  As recounted earlier, before 1972, the
basic structure of federal enforcement efforts was a lawsuit
seeking  to  hold  a  polluter  accountable  for  contributing  to
what  amounted  to  or  was  expressly  termed  a  violation  of
water  quality  standards.    Building  on  the  enforcement
model originally adopted in the 1948 Act, the 1965 amend-
ments of the WPCA required the adoption of “water quality
standards,” and they then provided that “violators” of these
standards  were  subject  to  suit  by  the  United  States.    79
Stat.  907–909.    That  is  where  matters  stood  until  1972
when  Congress  again  amended  the  WPCA  by  deleting  its
entire  text  and  substituting  what  is  now  popularly  called
the CWA.

This  overhaul  of  the  WPCA  continued  to  require  the
adoption of water standards, 33 U. S. C. §1313, but the re-
vised  statutory  text  conspicuously  omitted  any  provision
authorizing either the United States or any other party to
bring suit against an entity whose discharges were contrib-
uting to a violation of those standards.

This omission cannot be viewed as accidental or inconse-
quential.  The repealed enforcement provision went to the
heart of what Congress viewed as a major defect in the old
scheme.  As we have noted, the 1972 overhaul aimed to fa-
cilitate  enforcement  by  “making  it  unnecessary  to  work
backward from an overpolluted body of water to determine
which point sources  responsible” and thus subject to
suit.  EPA  v.  California,  426  U. S.,  at  204.  Instead,  the
amended  WPCA  sought  to  achieve  “acceptable  quality
standards”  by  means  of  “direct  restrictions”  on  polluters.
Ibid.  The  Government’s  interpretation  would  undo  what
Congress  plainly  sought  to  achieve  when  it  scrapped  the

14

CITY AND COUNTY OF SAN FRANCISCO v. EPA

Opinion of the Court

WPCA’s backward-looking approach.12

C
It is a “ ‘fundamental canon of statutory construction that
the  words  of  a  statute  must  be  read  in  their  context  and
with a view to their place in the overall statutory scheme.’ ”
Utility  Air  Regulatory  Group  v.  EPA,  573  U. S.  302,  320
(2014) (quoting FDA v. Brown & Williamson Tobacco Corp.,
529 U. S. 120, 133 (2000)).  Thus, in construing §1311, we
must also take into account the broader statutory scheme,
and at least two features of that  scheme point in favor  of
our interpretation.

1
The  first  is  the  so-called  “permit  shield”  provision,  33
U. S. C. §1342(k), under which a permittee is deemed to be
in compliance with the CWA if it follows all the terms in its
permit.  This protection is very valuable because violations
of  the  CWA,  even  if  entirely  inadvertent,  are  subject  to
hefty penalties.  The CWA imposes a regime of strict civil
liability, see, e.g., United States v. Allegheny Ludlum Corp.,
366 F. 3d 164, 174 (CA3 2004), and a party that violates a
permit term may be fined up to $25,000 per day per viola-
tion.  §1319(d).  As  San  Francisco  explains,  it  may  take
months to gather the information necessary to detect a drop
below  the  applicable  water  quality  standards,  see  Tr.  of

——————

12 The dissent suggests that the 1972 Congress was displeased with the
prior enforcement regime because it was too burdensome for the Govern-
ment, not because it was unfair for entities against which enforcement
actions were brought.  See post, at 8–9 (BARRETT, J., dissenting in part).
But whether or not this assessment of Congress’s intent is correct, what
matters  for  present  purposes  is  that  Congress  deliberately  deleted  a
longstanding  provision  that  expressly  authorized  what  the  dissent
wishes to perpetuate.  The idea that Congress sought to preserve the old
enforcement mechanism by squirreling it away in §1311(b)(1)(B)’s inapt
language defies belief.

Cite as:  604 U. S. ____ (2025)

15

Opinion of the Court

Oral  Arg.  16,  and  after  substandard  water  quality  is  de-
tected, it may take some time to devise and implement ap-
propriate corrective measures.  Indeed, there may be occa-
sions (such as the multiple-discharger situation we discuss
below, see infra this page and 16), when there is nothing a
permittee can do to bring about a prompt correction.  For
these  reasons,  the  potential  civil  penalties  for  noncompli-
ance can mount up and reach enormous sums.  In a pending
suit against San Francisco regarding the Bayside facility,
the penalties sought are $10 billion.  See Tr. of Oral Arg.
102.  In addition to all this, a permittee who is found to have
acted “knowingly” or even “negligently” may be criminally
prosecuted.  §1319(c).

Because of the harsh penalties for violating the terms of
a permit, the permit shield is invaluable.  Because of it, a
discharger that complies with all permit conditions can rest
assured that it will not be penalized.  But the benefit of this
provision  would  be  eviscerated  if the  EPA  could  impose a
permit provision making the permittee responsible for any
drop in water quality below the accepted standard.  A per-
mittee could do everything required by all the other permit
terms.  It could devise a careful plan for protecting water
quality, and it could diligently implement that plan.  But if,
in the end, the quality of the water in its receiving waters
dropped below the applicable water quality levels, it would
face dire potential consequences.  It is therefore exceedingly
hard  to  reconcile  the  Government’s  interpretation  of
§1311(b)(1)(C) with the permit shield.  And contrary to the
Government’s contention, the possibility that a court might
ultimately exercise its “broad discretion” to mitigate penal-
ties, see Brief for Respondent 44 (internal quotation marks
omitted), is not enough to make up for disarming the shield.

2
One final structural feature cements the case against the
EPA’s interpretation: the absence of any provision dealing

16

CITY AND COUNTY OF SAN FRANCISCO v. EPA

Opinion of the Court

with the problem that arises when more than one permittee
discharges  into  a  body  of  water  with  substandard  water
quality.  As previously explained, it is hard to believe that
the  1972  Congress  used  §1311(b)(1)(C)  to  perpetuate  (in
camouflaged  form)  the  backward-looking  enforcement
scheme in the prior version of the WPCA.  And it is even
harder  to  accept  the  proposition  that  Congress  did  that
without setting out any method for dealing with the multi-
discharger problem.  “here may be dozens or even hun-
dreds of . . . permitted and unpermitted discharges into the
same waterbody.”  Brief for National Mining Association et
al. as Amici Curiae 9.  In such situations, the pre-1972 en-
forcement scheme made it necessary for federal authorities
to “unscramble the polluted eggs after the fact.”  Wilming-
ton v. United States, 157 Fed. Cl. 705, 710 (2022).  By 1972,
it  was  recognized  that  this  was  impractical,  yet  the  EPA
maintains that Congress retained the backward-looking ap-
proach without making any attempt to address the vexing
multiple-discharger problem.

The EPA’s only response to this argument is to note that
in this case the Oceanside facility is the only entity that dis-
charges into the relevant area of the Pacific Ocean.  But the
multiple-discharger  problem  goes  to  the  meaning  of
§1311(b)(1)(C),  and  that  provision  cannot  mean  one  thing
in a single-discharger case and another when there are mul-
tiple dischargers.13

——————

13 In response to our arguments about the two structural features dis-
cussed  above,  the  dissent  contends  that  our
interpretation  of
§1311(b)(1)(C) is not necessary to protect permittees because even with-
out that interpretation a permittee subjected to an end-result provision
could challenge it as arbitrary and capricious.  See post, at 10–12 (opinion
of BARRETT, J.).  Of course, that response is no answer to our argument
that §1311(b)(1)(C) does not authorize end-result provisions in the first
place.    And  in  any  event,  it  is  not  clear  that  individual  arbitrary-and-
capricious challenges would provide adequate protection.  Unless some
form  of  judicial  relief  could  be  obtained  before  an  end-result  provision

Cite as:  604 U. S. ____ (2025)

17

Opinion of the Court

IV
Before concluding, we briefly address three additional ar-

guments advanced by the Government.

A
The EPA maintains that the imposition of end-result lim-
itations is the best course of action when “the information
necessary to develop additional ‘effluent limitations’ is un-
available.”  Brief for Respondent 41.  And it complains that
it  should  not  bear  the  burden  of  determining  what  a  per-
mittee should do to protect water quality because a permit-
tee is likely to have better access to necessary information
and a superior understanding of the operation of its facility
and the changes that could be made to provide further pro-
tection for water quality.

We  are  not  moved  by  this  argument.    For  one  thing,  it
appears that the EPA and state permitting authorities have
used  end-result  requirements  routinely,  not  just  when  a
permit holder has failed to provide necessary information.
See In re Lowell, 18 E. A. D. 115, 176 (EAB 2020); App. to
Pet. for Cert. 519.  And in any event, the EPA possesses the
expertise (which it regularly touts in litigation) and the re-
sources necessary to determine what a permittee should do.
It is also armed with ample tools to deal with situations in
which a permittee is slow to provide needed information or
is otherwise uncooperative.  The EPA can set a schedule for
the provision of information and can refuse to issue a per-
mit until the permittee complies.  If necessary, it can make
use of its emergency powers.  See 33 U. S. C. §1364.14

——————
took effect, a permittee’s potential liability could reach astronomical pro-
portions before the challenge was finally resolved.

14 The dissent argues that end-result provisions are in the best inter-
ests  of  regulated  entities  because  the  alternative  may  be  delay  in  the
issuance of permits.  Post, at 14 (opinion of BARRETT, J.).  If that were
true,  one  would  expect  regulated  parties  to  favor  such  provisions,  but
none has done so.  On the contrary, a long list of municipalities and other

18

CITY AND COUNTY OF SAN FRANCISCO v. EPA

Opinion of the Court

B

The  EPA  contends  that  Congress  authorized  the  use  of
end-result requirements when it codified the Agency’s CSO
Policy in 1994, see 33 U. S. C. §1342(q)(1).  And in support
of that argument, it cites language in the policy that per-
tains to phase I permits.  But the permit in question here is
a phase II permit, and the EPA does not claim that its in-
terpretation is supported by any CSO Policy provision re-
lating to such permits.15

In  any  event,  the  phase  I  language  to  which  the  EPA
points  does  not  authorize  the  imposition  of  end-result  re-
quirements.  The policy states that a phase I permit should
require  a  permittee  to  “omply  with  applicable   . . . expressed in the form of a narrative

——————
permittees support San Francisco’s position.  See supra, at 2; infra, at
19–20.  These sophisticated entities are better positioned than the dis-
sent to judge what is good for them.

15 In fact, the CSO Control Policy specifies exactly what a phase II per-
mit  should  contain,  and  those  requirements  are  inconsistent  with  the
end-result  limitation  that  the  EPA  imposes  here.    Under  the  policy,  a
phase  II  should  contain:  (1)  “equirements  to  implement  the
technology-based  controls”;  (2)  “arrative  requirements  which  insure
 that the selected CSO controls are implemented, operated and main-
tained  as  described  in  the  long-term  CSO  control  plan”;  (3)  “ater
quality-based effluent limitations . . . requiring, at a minimum, compli-
ance with . . . numeric performance standards for the selected CSO con-
trols”; (4) “ requirement to implement, with an established schedule,
the approved post-construction water quality assessment program”; (5)
“ requirement to reassess overflows to sensitive areas in those cases
where elimination or relocation of the overflows is not physically possible
and  economically  achievable”;  (6)  “onditions  establishing  require-
ments for maximizing the treatment of wet weather flows”; and (7) “
reopener clause authorizing the NPDES authority to reopen and modify
the permit upon determination that the CSO controls fail to meet   or  protect  designated  uses.”    59  Fed.  Reg.  18696.
Again,  although  the  purpose  is  to  improve  the  quality  of  the  relevant
bodies  of  water,  these  permitting  components  all  relate  to  the  dis-
chargers’ behavior and the permitting authority’s supervision of that be-
havior.

Cite as:  604 U. S. ____ (2025)

19

Opinion of the Court

limitation.”  59 Fed. Reg. 18696 (emphasis added).  Our de-
cision  does  not  rule  out  “narrative  limitations.”    “Limita-
tions,” as we understand the term, see supra, at 10–11, are
permitted under §1311(b)(1)(C), and limitations may be ex-
pressed in both numerical and non-numerical (i.e., “narra-
tive”) form.

Attempting to read more into the phase I language, the
EPA cites guidance it issued in 1995, but Congress did not
codify that guidance, and we are not obligated to accept ad-
ministrative guidance that conflicts with the statutory lan-
guage  it  purports  to  implement.  See  Loper  Bright  Enter-
prises v. Raimondo, 603 U. S. 369 (2024).  We also note that
other guidance issued by the EPA is arguably inconsistent.
See EPA, Combined Sewer Overflows: Guidance for Permit
Writers, at A–1 to A–7.

C
Finally, the EPA contends that the rejection of its inter-
pretation of 33 U. S. C. §1311(b)(1)(C) would have disrup-
tive  consequences for businesses that rely on “general per-
mits.”  Brief  for  Respondent  38;  Tr.  of  Oral  Arg.  83.
(General permits cover an entire category of point sources
in a given area.  See South Fla. Water Management Dist. v.
Miccosukee Tribe, 541 U. S. 95, 108, n. * (2004).)  Such per-
mits  are  important  for  certain  businesses,  such  as  home
builders, other construction companies, and certain agricul-
tural  enterprises,  see  Brief  for  National  Association  of
Home  Builders  et al.  as  Amici  Curiae  1,  11,  but  no  such
company has submitted a brief supporting the EPA’s inter-
pretation.  On the contrary, a brief filed on behalf of such
companies urges us to reject the EPA’s position.  Id., at 4–
7.  What is important, these companies tell us, are narra-
tive  limitations  other  than  end-result  requirements,  and
they specifically cite provisions demanding compliance with
“best-management  practices”  and  “operational  require-

20

CITY AND COUNTY OF SAN FRANCISCO v. EPA

Opinion of the Court

ments and prohibitions.”  Our decision allows such require-
ments.

V
In  sum,  we  hold  that  §1311(b)(1)(C)  does  not  authorize
the EPA to include “end-result” provisions in NPDES per-
mits.  Determining what steps a permittee must take to en-
sure that water quality standards are met is the EPA’s re-
sponsibility, and Congress has given it the tools needed to
make that determination.  If the EPA does what the CWA
demands, water quality will not suffer.

The judgment of the Ninth Circuit is reversed.

*

*

*

It is so ordered.

Cite as:  604 U. S. ____ (2025)

1

BARRETT, J., dissenting in part

SUPREME COURT OF THE UNITED STATES

_________________

No. 23–753
_________________

CITY AND COUNTY OF SAN FRANCISCO,
CALIFORNIA, PETITIONER v. ENVIRON-
MENTAL PROTECTION AGENCY

ON WRIT OF CERTIORARI TO THE UNITED STATES COURT OF
APPEALS FOR THE NINTH CIRCUIT



JUSTICE  BARRETT,  with  whom  JUSTICE  SOTOMAYOR,
JUSTICE KAGAN, and JUSTICE JACKSON join, dissenting in
part.

The Environmental Protection Agency issued San Fran-
cisco a permit allowing it to discharge pollutants from its
combined sewer system into the Pacific Ocean.  The permit,
of course, does not give the city free rein, and among its con-
ditions are prohibitions on discharges that contribute to a
violation of applicable water quality standards.  San Fran-
cisco  challenges  these  conditions  on  the  ground  that  EPA
lacks  statutory  authority  to  impose  them.  The  city  is
wrong.  The relevant provision of the Clean Water Act di-
rects EPA to impose “any more stringent limitation” that is
“necessary to meet . . . or required to implement any appli-
cable water quality standard.”  33 U. S. C. §1311(b)(1)(C).
Conditions  that  forbid  the  city  to  violate  water  quality
standards  are  plainly  “limitations”  on  the  city’s  license  to
discharge.

Notwithstanding  the  straightforward  statutory  lan-
guage, the Court sides with San Francisco.  I join Part II of
its  opinion,  which  rightly  rejects  the  city’s  primary  argu-
ment.  In Part III, however, the Court embraces an equally
weak theory—that the permit’s restrictions are not “limita-
tions,” as that word is ordinarily used.  The Court’s analysis

2

CITY AND COUNTY OF SAN FRANCISCO v. EPA

BARRETT, J., dissenting in part

is contrary to the text, so I respectfully dissent in part.

I
A
Under the Clean Water Act, “the discharge of any pollu-
tant by any person” is unlawful except as expressly author-
ized.  33 U. S. C. §1311(a).  As relevant here, authorization
comes in the form of “National Pollutant Discharge Elimi-
nation System (NPDES) permits,” which EPA (or, in some
circumstances, a State) may issue to allow discharges.  Be-
fore  issuing  a  permit,  however,  the  Agency  must  ensure
that  “such  discharge  will  meet  . . .  all  applicable  require-
ments”  under  several  different  statutory  provisions.
§1342(a)(1).

Section  1311(b)  is  one  such  provision.    It  works  in  two
steps  for  permits  like  San  Francisco’s.    First,  under
§1311(b)(1)(A),  EPA  must  set  “effluent  limitations”  that
“shall require the application of the best practicable control
technology currently available.”  “ ‘ffluent limitation’ ” re-
fers  to  a  restriction  “on  quantities,  rates,  and  concentra-
tions  of  chemical,  physical,  biological,  and  other  constitu-
ents which are discharged from point sources” into waters
subject to EPA’s jurisdiction.  §1362(11).

Second,  under  §1311(b)(1)(C),  EPA  must  impose  “any
more  stringent  limitation,  including  those  necessary  to
meet water quality standards, . . . or required to implement
any  applicable  water  quality  standard.”  Water  quality
standards—which are devised by the States and subject to
federal  approval—“consist  of  the  designated  uses  of  the
navigable waters involved and the water quality criteria for
such waters based upon such uses.”  §1313(c)(2)(A).  Efflu-
ent limitations, standing alone, are not always sufficient to
protect the desired water quality, as set forth in the water
quality  standards.  So  point  sources,  “ ‘despite  individual
compliance with effluent limitations, may be further regu-
lated to prevent water quality from falling below acceptable

Cite as:  604 U. S. ____ (2025)

3

BARRETT, J., dissenting in part

levels.’ ”    Arkansas  v.  Oklahoma,  503  U. S.  91,  101  (1992)
(quoting  EPA  v.  California  ex  rel.  State  Water  Resources
Control Bd., 426 U. S. 200, 205, n. 12 (1976)).  Importantly,
the  Act  does  not  itself  require  dischargers  to  heed  water
quality standards; the standards are enforceable only inso-
far  as  they  are  incorporated  into  permit  conditions  under
§1311(b)(1)(C).

Section 1311(b) therefore sets forth a coherent regime.  In
the  first  instance,  EPA  regulates  water  pollution  through
technology-based  effluent  limitations  that  restrict  the
“quantities, rates, and concentrations” of harmful materials
that permittees may discharge.  §1362(11).  But when the
technology-based effluent limitations are insufficient to en-
sure  that  the  water  quality  standards  are  met,  EPA  has
supplemental authority to impose further limitations.

B
As  the  Court  explains,  San  Francisco  operates  a  com-
bined  sewer  system,  which  transports  sewage  and  storm-
water runoff via the same conduits.  See ante, at 5–7.  Such
systems  occasionally  overflow  in  wet  weather—and  when
they  do,  they  discharge  both  stormwater  and  untreated
sewage into waters potentially regulated by the Clean Wa-
ter Act.  59 Fed. Reg. 18689 (1994).  As relevant here, “com-
bined  sewer  overflow”  events  from  one  component  of  San
Francisco’s  sewer  system  result  in  the  discharge  of  pollu-
tants into the Pacific Ocean via the Southwest Ocean Out-
fall, which is located within EPA’s jurisdiction, 3.3 nautical
miles off the coast of San Francisco.  These discharges are
presumptively unlawful under §1311(a) and hence require
a permit.

The  city’s  NPDES  permit  contains  both  the  technology-
based  effluent  limitations  required  by  §1311(b)(1)(A)  and
additional  limitations  to  protect  the  water  quality  stand-
ards  under  §1311(b)(1)(C).    This  latter  category  includes
two  “receiving  water  limitations”—requirements  defining

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BARRETT, J., dissenting in part

the  permissible  discharge  by  reference  to  its effect  on  the
quality of the waters that receive it, rather than by refer-
ence to the nature of the discharge itself.  (These are what
the Court calls “ ‘end-result’ requirements.”  Ante, at 2.)  The
first states that San Francisco “shall not cause or contribute
to  a  violation  of  any  applicable  water  quality  standard.”
App. to Pet. for Cert. 97.  The second provides that “ei-
ther the treatment nor the discharge of pollutants shall cre-
ate pollution, contamination, or nuisance” as defined by the
California Water Code.  Id., at 339.

The city’s permit thus tracks the structure of §1311(b).  It
restrains discharges initially through technology-based ef-
fluent  limitations,  as  required  by  §1311(b)(1)(A).    But  be-
cause the effluent limitations may be insufficient to ensure
that California’s water quality standards are met, the per-
mit  contains  supplemental  limitations,  as  required  by
§1311(b)(1)(C).  The concern that the technology-based ef-
fluent limitations may fall short is on display in this case—
discharges from components of San Francisco’s sewer sys-
tem  have  allegedly  led  to  serious  breaches  of  the  water
quality standards, such as “discoloration, scum, and float-
ing  material,  including  toilet  paper,  in  Mission  Creek.”
Complaint in United States v. City and County of San Fran-
cisco, No. 3:24–cv–02594 (ND Cal., May 1, 2024), ECF Doc.
1,  p.  22.  The  receiving  water  limitations  imposed  under
§1311(b)(1)(C) are included to ensure that such breaches do
not occur.

II
A
San  Francisco  dedicates  almost  all  its  briefing  to  the
proposition that the receiving water limitations are unlaw-
ful because §1311(b)(1)(C) allows only effluent limitations.
In other words, San Francisco reads the phrase “any more
stringent limitation” to mean “any more stringent effluent
limitation.”  As the Court explains, this argument is flatly

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5

BARRETT, J., dissenting in part

inconsistent with the text of §1311(b).  See ante, at 7–9.  In
my  view,  the  failure  of  that  argument  should  have  ended
this case.

The Court continues, however, with a theory largely of its
own  making.    Whatever  “any  more  stringent  limitation”
may mean, the Court says, it does not authorize EPA to di-
rect permittees to comply with the water quality standards.
This  conclusion  is  puzzling.    The  entire  function  of
§1311(b)(1)(C) is to ensure that permitted discharges do not
violate  state  water  quality  standards.    And  as  discussed
above, the provision gives EPA broad authority to achieve
that  aim  through  conditions  imposed  in  NPDES  permits.
Why would that broad authority not allow EPA to tell per-
mittees that they must not cause or contribute to a violation
of  the  very  standards  that  §1311(b)(1)(C)  serves  to  safe-
guard?

The answer, according to the Court, is that a restriction
does not count as a “limitation” if the permittee must iden-
tify the steps necessary to comply with it.  Ante, at 10.  San
Francisco’s  permit  only  authorizes  discharges  that  do  not
degrade water quality below the applicable standard.  It is
up to the city, however, to formulate a plan to achieve that
result.  The city’s plan, the Court asserts, is a “limitation”
on its discharges, but the permit condition is not.  See ibid.
As  best  I  can  tell,  the  Court  thinks  that  only  the  “direct
source  of  restriction  or  restraint”—apparently,  the  most
specific restriction—counts as a “limitation.”  Ibid.

The Court offers nothing to substantiate this proposition,
and it is wrong as a matter of ordinary English.  It is com-
monplace  for  “limitations”  to  state  “that  a  particular  end
result must be achieved and that it is up to the 
to figure out what it should do.”  Ibid.  For example, a com-
pany could impose spending “limitations” by requiring each
branch to spend no more than its allotted budget, while still
leaving branch managers flexibility to determine how to al-
locate those funds.  A doctor could impose a “limitation” on

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CITY AND COUNTY OF SAN FRANCISCO v. EPA

BARRETT, J., dissenting in part

a patient’s diet by telling the patient that she must lose 20
pounds over the next six months, even if the doctor does not
prescribe a specific diet and exercise regimen.  And an air-
line  could  impose  a  “limitation”  on  the  weight  of  checked
bags, even though it does not tell passengers what items to
pack.  “Limitations” can be general as well as specific, and
general limitations can call for more specific ones.

In this context, “limitation” is simply a synonym for “
restrictive  condition.”  Funk  &  Wagnalls  New  Standard
Dictionary of the English Language 1437 (1952).  And con-
ditions can be stated at many levels of generality—includ-
ing in terms of end results.  A college may condition a schol-
arship on the student’s maintenance of a minimum GPA.  A
homeowner  may  condition  payment  for  a  new  roof  on  the
contractor’s  satisfaction  of  industry  standards.    An  em-
ployer  may  condition  job  perks  on  the  employee’s  perfor-
mance.  In each example, the condition is a limitation on a
benefit or payment.  There are strings attached.

The Court also misconstrues §1311(b)(1)(C)’s reference to
limitations that are “necessary to meet” or “required to im-
plement”  the  water  quality  standards.    As  for  the  former
phrase, “necessary to meet” does not imply anything about
the specificity or concreteness of the limitations adopted by
EPA.  Rather, the limitations on San Francisco’s permit are
“necessary  to  meet”  the  water  quality  standards  because
without them, the standards would not bind the city.  The
limitations  thus  ensure  that  San  Francisco  will  “ ‘comply
with,’ ” “ ‘fulfill,’ ” “ ‘satisfy,’ ” or “ ‘come into conformity with’ ”
the water quality standards.  Ante, at 11 (quoting Random
House Unabridged Dictionary 1195 (2d ed. 1987)).

Nor  does  the  phrase  “required  to  implement”  help  the
Court.  “Implement,” the Court says, generally means “ ‘to
give practical effect to and ensure of actual fulfillment by
concrete measures.’ ”  Ante, at 11.  That is true but incom-
plete.  The full definition reads: “to carry out: ACCOMPLISH,
FULFILL, . . . esp.:  to  give  practical  effect  to  and  ensure  of

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7

BARRETT, J., dissenting in part

actual fulfillment by concrete measures.”  Webster’s Third
New  International  Dictionary  1134  (1976).    So  while  the
word  is  often  used  in  the  sense  of  taking  “concrete
measures,” such measures are not necessary to satisfy the
definition of “implement.”

Regardless, the receiving water limitations “implement”
the water quality standards in both the broad and narrow
senses of the word.  They are required to “carry out ac-
complish,  fulfill” the standards: When effluent limita-
tions fall short, discharges from the city’s combined sewer
system will otherwise degrade water quality below the ap-
plicable  standard.    Ibid.  (capitalization  altered).  And  the
limitations are “concrete measures,” ibid., because they are
the means by which EPA “implement any applicable wa-
ter quality standard,”  §1311(b)(1)(C).  They give the stand-
ards “practical effect” by making them enforceable.  Id., at
1134.

There is no getting around it: The receiving water limita-
tions are “limitations.”  If they are vague or unreasonable,
they  are  vulnerable  to  challenge  on  one  or  both  of  those
grounds.  See,  e.g.,  Natural  Resources  Defense  Council  v.
EPA, 808 F. 3d 556, 578 (CA2 2015) (invalidating a receiv-
ing water limitation as arbitrary and capricious).  But even
a vague or unreasonable limitation is still a “limitation.”

B
With the text of §1311(b)(1)(C) against it, the Court tries
to marshal support for its approach from the Clean Water
Act’s history, as well as from what the Court describes as
the  “broader  statutory  scheme.”    Ante,  at  12–16.    Neither
helps.

1

As for the statutory history: Advancing a specific theory
of the congressional intent behind the Clean Water Act, the
Court contends that EPA’s interpretation would revive the

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CITY AND COUNTY OF SAN FRANCISCO v. EPA

BARRETT, J., dissenting in part

“backward-looking” policy regime that the Act was designed
to replace.  See ante, at 12–14.  Before the Act, the United
States  enforced  federal  water  pollution  laws  primarily
through  abatement  actions.    See  33  U. S. C.  §1160  (1970
ed.).  Though  the  Act  abolished  this  cause  of  action,  the
Court  claims  that  receiving  water  limitations  function  in
essentially  the  same  way.    Just  as  the  United  States  did
when it brought abatement suits, EPA would have to “ ‘work
backward from an overpolluted body of water’ ” to combat
water pollution.  Ante, at 13 (quoting State Water Resources
Control Bd., 426 U. S., at 204).  Thus, the Court insists, the
use  of  receiving  water  limitations  would  “undo”  the  Act’s
shift from abatement suits to “ ‘direct restrictions’ on pollut-
ers.”  Ante,  at  13  (quoting  State  Water  Resources  Control
Bd., 426 U. S., at 204).

Of course, no theory of “what Congress plainly sought to
achieve,” ante, at 13–14, could justify an implausible inter-
pretation of §1311(b)(1)(C).  Here, however, the Court does
not  even  deliver  on  the  claim  that  its  account  “plainly”
tracks Congress’s goal.  Ante, at 13–14.  Because receiving
water  limitations  do  not  actually  replicate  the  old  abate-
ment  regime,  the  Court’s  rendition  is  not  the  only  (much
less the most obvious) explanation for the statutory before
and  after.  There  is  another  explanation,  and  it  is  one  in
which receiving water limitations fit right in.

Under  the  old  system,  the  United  States  could  bring
abatement actions only after the pollution had already oc-
curred.  See  33  U. S. C.  §1160(c)(5)  (1970  ed.).    A  glaring
problem with this approach is that an ex post enforcement
regime does not adequately deter polluters or prevent pol-
lution.  Making matters worse, this regime involved “cum-
brous enforcement procedures” that made it next to impos-
sible  to  bring  abatement  actions.  State  Water  Resources
Control  Bd.,  426  U. S.,  at  202;  see  also  33  U. S. C.  §1160
(1970 ed.) (requiring, prior to an abatement action, that the

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9

BARRETT, J., dissenting in part

United States hold a conference of the relevant state agen-
cies, then provide the state agency six months to take reme-
dial action, then call a public hearing with the state agency
and  the  discharger);  K.  Murchison,  Learning  From  More
Than Five-and-a-Half Decades of Federal Water Pollution
Control  Legislation:  Twenty  Lessons  for  the  Future,  32
Env. Aff. 527, 534 (2005) (“According to a report prepared
by the Senate Committee on Public Works, the federal gov-
ernment  initiated  only  one  enforcement  action  under  the
Federal Water Pollution Control Act prior to 1970”).

The

Congress  chose  a  different  regulatory  model  when  it
adopted  the  Act  in  1972.    The  Act  renders  all  discharges
presumptively unlawful.  Then, under the current ex ante
permitting  regime,  EPA  authorizes  only  those  discharges
that comply with the Act.  Should a permittee fail to comply
with  the  terms  of  its  permit,  EPA  has  broad  authority  to
sue.  See 33 U. S. C. §§1319(b)–(d) (authorizing civil actions
for  injunctive  relief,  civil  penalties  for  violations,  and  in
some instances criminal sanctions).
receiving  water

imposed  under
§1311(b)(1)(C)  are  entirely  consistent  with  this  scheme.
Again,  the  technology-based  effluent  limitations  imposed
under  §1311(b)(1)(A)  do  the  primary  work  of  gating  dis-
charges  at  the  front  end  to  minimize  pollution.    The
§1311(b)(1)(C) limitations guard against any residual risk
that  discharges  will  violate  the  water  quality  standards.
Because these limitations supplement rather than replace
the  technology-based  effluent  limitations,  there  is  no  risk
that broadly worded receiving water limitations will recre-
ate the ineffective abatement regime that prevailed prior to
1972.

limitations

Furthermore,  the  receiving  water  limitations  operate
within the broader context of the Act’s permitting regime.
These permits impose a prospective requirement on permit-
tees  to  comply  with  permit  conditions.    Under  the  old  re-
gime, a discharger could take an approach of “pollute first

10

CITY AND COUNTY OF SAN FRANCISCO v. EPA

BARRETT, J., dissenting in part

and apologize later,” secure in the knowledge that an abate-
ment suit was unlikely and that such a suit would at most
allow  judgment  to  “secur  abatement  of  any  pollution
proved.”  33 U. S. C. §1160(h) (1970 ed.).  A permittee who
violates a permit condition, by contrast, necessarily exposes
itself  to  enforcement  actions  by  EPA,  as  well  as  potential
penalties.  See 33 U. S. C. §§1319(b)–(d).  Receiving water
limitations, like any other permit condition, thus operate as
“ ‘direct  restrictions’  on  polluters.”    Ante,  at  13  (quoting
State Water Resources Control Bd., 426 U. S., at 204).

2

The  Court  also  claims  that  the  receiving  water  limita-
tions  are  inconsistent  with  two  features  of  the  “broader
statutory scheme.”  Ante, at 14–16.  First, it contends that
the receiving water limitations are at odds with the permit
shield provision because violations of the permit condition
(and the attendant liability) are hard to predict.  Ante, at
14–15.  Second, it argues that the Clean Water Act is silent
about  the  problem  of  multiple  dischargers  into  the  same
body of water—and if the Act allowed EPA to condition a
permit on maintaining water quality standards, the Court
says, it surely would have spelled out how to deal with such
an obvious complication.  Ante, at 15–16.  Both of these ar-
guments boil down to the Court’s concern that receiving wa-
ter limitations might be unfair to permittees.  In some cir-
cumstances, they might be.  But any unfairness should be
addressed  through  arbitrary-and-capricious  challenges—
not a statutory rewrite.

Start with the permit shield provision.  Under §1342(k),
compliance  with  the  terms  of  a  permit  “shall  be  deemed
compliance” with various substantive provisions of the Act,
thereby shielding permit holders from liability.  The Court
insists  that  receiving  water  limitations  like  those  in  the
city’s permit would “eviscerat” that benefit by failing to
provide fair notice.  Ante, at 14–15.

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11

BARRETT, J., dissenting in part

The permit shield provision, however, serves the specific
role of immunizing permittees that comply with a permit.
See  §1342(k).    For  instance,  it  “insulate  permit  holders
from changes in various regulations during the period of a
permit” and “relieve them of having to litigate in an en-
forcement  action  the  question  whether  their  permits  are
sufficiently strict.”  E. I. du Pont de Nemours & Co. v. Train,
430 U. S. 112, 138, n. 28 (1977).  The receiving water limi-
tations do not eliminate that benefit.  It remains true that
San  Francisco  cannot  be  sued  under  the  theory  that  the
city’s permit is insufficient to ensure compliance with the
Act.

Really, the Court’s argument reduces to the broader pol-
icy concern that it may be difficult for regulated entities to
comply with receiving water limitations and that they may
lack adequate notice of a violation.  But again, that concern
goes to the question whether  a particular receiving water
limitation is rational.  If a permittee cannot reasonably de-
termine  how  to  comply  with  a  receiving  water  limitation,
then the permit condition may be invalidated as arbitrary
and capricious.  (In fact, San Francisco made arbitrary-and-
capricious arguments below, but the Ninth Circuit rejected
them; the city did not seek this Court’s review of that issue.
See  75  F.  4th  1074,  1092–1093  (2023).)  And  as  EPA
acknowledged at oral argument, the Agency “may not im-
pose  limitations  of  any  kind  that  are  unconstitutionally
vague.”  Tr. of Oral Arg. 51.  These concerns do not speak to
the relevant question here, which is whether receiving wa-
ter limitations comport with the Act.

The Court is also wrong to suggest that receiving water
limitations  are  categorically  impermissible  because  there
may be multiple dischargers into one body of water in some
circumstances.  See ante, at 15–16.  It makes little sense to
say that an agency always lacks authority to take a certain
action  just  because  the  action  would  be  unreasonable  in
some scenarios.  And as the Court itself recognizes, there is

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CITY AND COUNTY OF SAN FRANCISCO v. EPA

BARRETT, J., dissenting in part

no multiple-discharger problem here: San Francisco is the
only significant discharger at the Southwest Ocean Outfall.
Ante, at 16.  If EPA does start imposing receiving water lim-
itations  in  contexts  where  permittees  cannot  control  the
quality  of  the  receiving  waters—such  as  where  there  are
multiple dischargers—then, again, the permittee can bring
an arbitrary-and-capricious challenge.

3
Finally, the Court downplays the valuable uses of receiv-
ing water limitations.  To begin, EPA imposes such limita-
tions when the Agency “lacks the information necessary to
develop  more  tailored  limitations.”   Tr.  of  Oral  Arg.  51.
That is the case here: San Francisco has consistently failed
to  update  its  Long-Term  Control  Plan  for  managing  com-
bined  sewer  overflows.    See  75  F.  4th,  at  1095  (observing
that San Francisco has not updated its plan since 1991).  By
imposing  receiving  water  limitations,  EPA  was  neverthe-
less able to issue a permit to San Francisco while complying
with the Clean Water Act.

The  Court  does  not  explain  what  other  course  of  action
EPA  could  take.    Instead,  it  states,  without  citation,  that
“EPA possesses the expertise . . . and the resources neces-
sary to determine what a permittee should do.”  Ante, at 17.
This  bare  assertion  simply  ignores  the  obvious  problem—
how is EPA expected to deploy its expertise when it lacks
the  basic  information  necessary  to  make  a  decision?    The
Court also suggests that the Agency could refuse to issue a
permit  until  the  applicant  provides  the  necessary  infor-
mation.  Ibid.    But  this  gives  the  game  away:  The  entire
point of EPA’s argument is that it is preferable for EPA to
impose  broadly  worded  conditions  in  its  permits  than  to
deny  permits  altogether  and  potentially  shut  down  San
Francisco’s sewer system.  Nor can EPA simply “make use
of  its  emergency  powers”  when  permittees  fail  to  provide
necessary  information.  Ibid.    Such  powers  are  available

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13

BARRETT, J., dissenting in part

only  when  there  is  “imminent  and  substantial  endanger-
ment to the health of persons or to . . . the livelihood of . . .
persons.”  §1364(a).  As  the  name  “emergency”  suggests,
these powers provide a limited avenue for the Agency to sue
in response to a crisis.  They do not provide a solution to the
problem of non-compliant permittees.

Receiving water limitations are also useful when EPA is-
sues  general  permits  to  broad  categories  of  dischargers
(such  as  for  construction  projects).    See  South  Fla.  Water
Management  Dist.  v.  Miccosukee  Tribe,  541  U. S.  95,  108,
n. (2004) (observing that such “permits greatly reduce . . .
administrative  burden  by  authorizing  discharges  from  a
category  of  point  sources  within  a  specified  geographic
area”).  In lieu of individualized and prescriptive permitting
conditions—which would take time to craft and with which
small businesses might have difficulty complying—EPA in-
stead allows the permittee to proceed under more general
language.  EPA can therefore issue the permit quickly and
give responsible permittees flexibility to choose how to com-
ply with the permit.

After today, the alternative for entities seeking a general
permit  is  not  for  EPA  to  issue  the  permit  without  the
§1311(b)(1)(C) limitation.  Instead, the alternative is for the
permit to be delayed or even denied.  See Tr. of Oral Arg. 83
(If the Court “take away  ability to rely on these
sorts of prohibitions,” then the Agency is “going to need to
ask for more information because it’s only with that infor-
mation” that the Agency can “develop more tailored limita-
tions”).  Section  1311(b)(1)(C)  is  not  optional;  EPA  is  re-
quired to issue the limitations necessary to ensure that the
water  quality  standards  are  met.    So  taking  a  tool  away
from EPA may make it harder for the Agency to issue the
permits  that  municipalities  and  businesses  need  in  order
for their discharges to be lawful.

The  Court  dismisses  this  concern,  noting  that  “no  . . .

14

CITY AND COUNTY OF SAN FRANCISCO v. EPA

BARRETT, J., dissenting in part

company has submitted a brief supporting . . . EPA’s inter-
pretation.”  Ante, at 19.  But there is no reason to think that
the  sampling  of  trade  associations  from  which  this  Court
happens to hear reflects the views of all potentially affected
parties.  And  in  any  event,  neither  the  cited  amicus  brief
nor the Court itself has any response to EPA’s straightfor-
ward point: If the Agency must impose individualized con-
ditions for each permittee under §1311(b)(1)(C), then it will
be more difficult and more time consuming for the Agency
to issue permits.

*

*
Receiving  water  limitations  are  not  categorically  incon-
sistent with the Clean Water Act.  Because the Court holds
otherwise, I respectfully dissent in part.

*

