USA, California, Golden Gate Bridge in the evening

The landmark decision alters the NPDES permit landscape, shifting the focus to specific actions over general outcomes.

By Michael G. Romey, Benjamin D. Gibson, Lucas I. Quass, Phil Goldberg, and Cody M. Kermanian

On March 4, 2025, the US Supreme Court issued its decision in City and County of San Francisco v. Environmental Protection Agency, 145 S.Ct. 704 (2025), which held that while the Clean Water Act (CWA) authorizes the inclusion of narrative (non-numeric) criteria in National Pollutant Discharge Elimination System (NPDES) permits, it does not authorize “end-result” requirements. End-result requirements are provisions in an NPDES permit that do not specify what actions a permittee must take or refrain from taking. Instead, end-result requirements place the responsibility for achieving specific water quality results in the receiving water body on the discharging facility itself, rather than specifying the actions the facility must take to comply with water quality standards. The Court emphasized that the Environmental Protection Agency (EPA) is responsible for determining and specifying the necessary steps to ensure compliance with water quality standards.

The Supreme Court’s decision has significant implications for NPDES permit drafting and compliance moving forward. The ruling clarifies that the CWA does not authorize the inclusion of end-result requirements in NPDES permits. The decision should therefore effectively render all EPA and State CWA NPDES permit end-result criteria, which are widespread, unenforceable.

Background

The CWA regulates the discharge of pollutants into the waters of the United States, which refers to bodies of water, including rivers, lakes, streams, and wetlands, that are subject to federal regulation under the CWA for the purpose of protecting water quality. A key component of the CWA is NPDES, which requires dischargers to obtain permits for certain discharges into waters of the United States. NPDES permits often include “effluent limitations” that specify the quantities and concentrations of pollutants that may be discharged into receiving waters. NPDES permits commonly also set forth testing, record-keeping, and reporting requirements, and prescribe specific practices that permittees must undertake to reduce pollutant loads. The Supreme Court’s opinion calls such conditions “narrative” water quality standards, and distinguishes between narrative water quality standards and the end-result requirements. Under the “permit shield” provision, an entity that adheres to the terms of its permit is deemed compliant with the CWA.1 However, failure to comply with all permit terms can expose permittees to civil penalties and criminal prosecution.

City and County of San Francisco v. Environmental Protection Agency centers around two end-result requirements in San Francisco’s NPDES permit for the Oceanside wastewater treatment facility, which discharges into the Pacific Ocean. The first end-result requirement prohibited the Oceanside facility from making any discharge that would contribute to a violation of any applicable water standard for the receiving water. The second requirement prohibited the city from performing any treatment or making any discharge that would create “pollution, contamination, or nuisance as defined by California Water Code section 13050.” These requirements held San Francisco accountable for the quality of the receiving waters into which it discharged, without specifying the actions needed to achieve compliance.

The California Regional Water Quality Control Board for the San Francisco Bay Region and the EPA approved the final Oceanside NPDES permit. San Francisco appealed to the EPA’s Environmental Appeals Board, which rejected San Francisco’s challenge. San Francisco then filed a petition for review in the Ninth Circuit, which was denied by a divided panel that determined the CWA authorizes the EPA to impose “any” limitations to ensure that applicable water quality standards are satisfied in a receiving body of water.2

In City of San Francisco v. U.S. Envtl. Prot. Agency, a divided US Court of Appeals for the Ninth Circuit panel held that narrative prohibitions, including end-result provisions, are consistent with the CWA and its implementing regulations, which provide broad authority to impose limitations necessary to ensure water quality standards.3 The Ninth Circuit rejected San Francisco’s arguments that such provisions are too vague, noting they serve as a backstop to ensure compliance with water quality standards not addressed by specific effluent limitations.4 The Ninth Circuit noted that such provisions are not only authorized, but they are required when necessary to satisfy applicable water standards.5

Supreme Court Majority Decision

San Francisco challenged the end-result provisions in the US Supreme Court, arguing that they exceeded the EPA’s statutory authority under the CWA. The City alleged that the relevant CWA provision, 33 U.S.C. Section 1311(b)(1)(C), only allows the EPA to impose specific limitations on discharges, rather than general requirements that hold a permittee responsible for achieving water quality standards in a receiving water. Justice Alito delivered the majority opinion6 and was joined by Justices Roberts, Thomas, Kavanaugh, and Gorsuch with respect to Part III (5-4) and all of the Justices except Justice Gorsuch with respect to Part II (8-1) of the opinion. In Part III, the Supreme Court held that the EPA exceeded its authority under the CWA by including end-result provisions in NPDES permits. The Court based its decision on the text of Section 1311(b)(1)(C), the history of federal water pollution control, and the broader statutory scheme of the CWA. In Part II the Court dismissed the city’s argument that all “limitations” imposed under Section 1311(b)(1)(C) must qualify as effluent limitations. Each Part of the opinion is discussed in further detail below.

Part II

In Part II of the majority opinion, eight justices rejected San Francisco’s main argument that all “limitations” imposed under Section 1311(b)(1)(C) must qualify as effluent limitations.7 The Court noted that Congress included particular language to specify effluent limitations in other sections of the CWA, so the omission of such language from Section 1311(b)(1)(C) is presumed to be intentional and purposeful. Further, the Court found San Francisco’s interpretation would eliminate the EPA’s authority to introduce narrative provisions or require a loose reading of an effluent limitation, both of which the Court recognized as undesirable results.8

Part III

As an initial matter, the Court noted the text of Section 1311(b)(1)(C) requires a permit to contain, in addition to “effluent limitations,” “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 implement any applicable water quality standard established pursuant to this chapter”9 (emphasis added by the Court). The Court found that the term “limitation” in the context of the CWA refers to specific instructions imposed by the EPA, not general end-result requirements, and that “limitations” must be concrete measures that permittees must follow to achieve water quality goals.10 In considering the history of the CWA, the Court emphasized that the 1972 amendments to the Water Pollution Control Act (WPCA), which became the CWA, moved away from a backward-looking approach to enforcement (i.e., beginning with a determination that a water body was polluted and then proving that a particular entity was responsible) in favor of direct restrictions on an entity’s discharges.11 Accordingly, the Court interpreted the EPA’s reading of the CWA as constituting a return to the WPCA approach, against congressional intent.12

In considering the broader statutory scheme of the CWA, the Court determined that the permit shield provision and the “multiple dischargers” issue both favor an interpretation of the CWA that does not allow the EPA to impose end-result requirements. The permit shield provision protects compliant permittees from liability, and the Court states that end-result requirements would negate this protection by exposing permittees to penalties even if they adhere to all specified permit terms.13 Further, the Court notes that the CWA does not provide a mechanism for allocating responsibility among multiple dischargers contributing to water quality violations, which would be necessary if end-result requirements were allowed.14

The Court dismissed the EPA’s argument that general end-result provisions are an acceptable stopgap when information necessary to develop effluent limitations is unavailable. The Court reasoned that the EPA possesses the expertise and resources necessary to determine the specific actions that permittees should take to meet water quality standards.15 Likewise, the Court was not swayed that business and municipalities would be harmed by the elimination of end-use requirements, noting that no company filing an amicus brief supported the EPA’s interpretation.16

The Dissent

Justice Barrett’s dissent to Part III, joined by Justices Sotomayor, Kagan, and Jackson, argues that the CWA’s language allows for end-result provisions and that such provisions are beneficial when detailed information is lacking, so as to prevent delays in permit issuance. The dissent disagrees with the majority’s interpretation of “limitations,” asserting that the term can, and commonly does, encompass general conditions that require permittees to achieve specific end results, and that limitations do not need to be narrowly defined as specific actions.17 Regarding the 1972 amendments to the WPCA/CWA, the dissent offers an alternative congressional intent to the one advanced by the majority.18 Instead of taking the majority’s approach and focusing on the point of regulation (discharger versus receiving waters), the dissent instead emphasizes that the timing of enforcement changed from ex post under the WPCA to ex ante under the CWA. Under the WPCA, the United States could only bring abatement actions after the pollution had occurred, whereas the CWA renders all discharges presumptively unlawful and authorizes only those discharges that comply with the CWA. The dissent therefore argues that receiving water limitations are consistent with the CWA’s goal of preventing water quality violations as a supplementary tool to specific effluent limitations.19

The dissent claims that the permit shield would still protect permittees from liability if they comply with permit terms, including end-result provisions, and that any fairness or notice concerns are better addressed through arbitrary and capricious challenges to specific permit conditions.20 The dissent also notes that the Oceanside facility is the only significant discharger at the Southwest Ocean Outfall, so the multiple discharger issue is not relevant in this instance and, in any case, does not justify categorically prohibiting receiving water limitations.21

The dissent highlights the practical benefits of receiving water limitations, including providing flexibility to the EPA and permittees and allowing for timely permit issuance.22 This flexibility is particularly important when detailed information is unavailable, allowing permits to be issued in a timely manner without unnecessary delays.

Possible Implications of the Decision

As an initial matter, the Court’s decision has broad implications on the inclusion of end-result requirements in NPDES permits, including that the EPA may no longer rely on Section 1311(b)(1)(C) for authority to include end-result provisions in NPDES permits.

End-result requirements are extremely common in NPDES permits and a frequently used method by agencies to administer certain programs. For instance, California’s Regional Water Quality Control Boards often build compliance with basin plans, beneficial uses, and sediment quality objectives into NPDES permits through end-use requirements. Moving forward, the EPA and State agencies will need to alter their permitting approach and impose more detailed and precise permit conditions to implement similar requirements. This may reduce ambiguity and help permittees better understand their compliance obligations. However, future litigation is possible regarding what qualifies as a permissive narrative versus impermissible end-result provision. Agencies could consider numeric limitations or expanded or more specific best management practices (or other compliant narrative restrictions). For State requirements, State agencies may adopt State law mechanisms instead of the CWA (e.g., the California Porter-Cologne Water Quality Act).

While the majority notes that Congress has granted the EPA the tools needed to develop new numeric limitations, this is a major expansion of agency workloads in a time of limited resources generally.23 As the EPA adjusts to the requirement for more specific permit conditions, delays may occur in the issuance of permits, particularly for complex facilities or those with limited data, resulting in potential impacts to industries that depend on timely permit approval for operations. Broader establishment of numeric limitations in general permits may also create more situations in which a numeric standard is not workable for a given discharger.

If more numeric limitations are adopted, that may create more potential legal exposure by presenting would-be plaintiffs with more targets for litigation.

  1. See, 33 U.S.C. § 1342(k). ↩︎
  2. See, 33 U. S. C. §1311(b)(1)(C)). ↩︎
  3. City of San Francisco v. U.S. Envtl. Prot. Agency,75 F.4th 1074, 1093 (9th Cir. 2023). ↩︎
  4. Id. at 1091. ↩︎
  5. Id. at 1090. ↩︎
  6. Justice Alito also authored the majority opinion in Sackett v. EPA that reversed the Ninth Circuit’s conclusion that the CWA covered wetlands with an ecologically significant nexus to traditional navigable waters. ↩︎
  7. City & Cnty. of San Francisco, at 713-14. ↩︎
  8. Id. at 714. ↩︎
  9. Id. at 715. ↩︎
  10. Id. at 715-16. ↩︎
  11. Id. at 716-17. ↩︎
  12. Id. at 717. ↩︎
  13. Id. at 717-18. ↩︎
  14. Id. at 718. ↩︎
  15. Id. at 719. ↩︎
  16. Id. at 720. ↩︎
  17. City & Cnty. of San Francisco, at 722-24 (Barrett, J., dissenting). ↩︎
  18. Id. at 724-25. ↩︎
  19. Id. at 725. ↩︎
  20. Id. at 725-26. ↩︎
  21. Id. at 726. ↩︎
  22. Id. at 726-27. ↩︎
  23. City & Cnty. of San Francisco, at at 720. ↩︎