What happened?
The U.S. Supreme Court issued a divided opinion on March 4, 2025, that reversed a Ninth Circuit decision upholding a National Pollutant Discharge Elimination System (NPDES) permit issued to San Francisco for its combined sewer system treatment facility.
What did the Supreme Court hold?
The Supreme Court held that the federal Clean Water Act (CWA) does not allow EPA or authorized state agencies to impose in NPDES permits so-called “end-result” limits—those that make a permittee directly responsible for the quality of the water in the body of water into which the permittee discharges pollutants.
Why Does It Matter?
The decision matters because, as a result of the Supreme Court’s holding, EPA, as well as authorized state agencies such as the Minnesota Pollution Control Agency, are now precluded from including in NPDES permits certain narrative conditions frequently found in many current NPDES permits, such as those prohibiting the permittee from creating nuisance conditions or causing or contributing to a violation of water quality standards in the water body receiving the permittee’s discharge. What this will mean in practice is less clear. Being unable to use these types of conditions could result in agencies issuing less-protective permits. Conversely, if agencies take the time to develop specific steps permittees must take to protect the receiving water to the same extent as the former “end-result” limitations did, this could result in more work for the agencies and a delay in the permitting process. The court’s decision also could have the benefit of making it easier for permittees to be protected by the Clean Water Act’s “permit shield,” since the vagueness of some end-result permit conditions can make it difficult for a permittee to demonstrate compliance, as required for the permit shield.
Background
On March 4, 2025, the United States Supreme Court issued a divided opinion with significant implications for federal and state NPDES permit programs. City and County of San Francisco v. U.S. Environmental Protection Agency, March 4, 604 U.S. ------- (2025). By rejecting what the court termed “end-result” permit limitations—those that make a permittee directly responsible for water quality in the body of water into which the permittee discharges—the court has removed a key tool for regulators seeking to craft NPDES permits protective of receiving waters.
The case involved San Francisco’s combined sewer system, a wastewater collection system typical of many municipalities that conveys both sewage and stormwater through shared pipes to a treatment facility. The city’s facility discharges treated wastewater into the Pacific Ocean through multiple discharge points, including a primary discharge point (Point No. 001) that is more than 3 miles from shore. Because of this distance, Point no. 001 is under exclusive federal jurisdiction; so, the city’s NPDES permit for the treatment facility is issued jointly by EPA and the California Regional Water Quality Control Board for the San Francisco Bay Region, which has delegated authority to implement the NPDES permit program. During heavy precipitation, the city’s treatment facility can exceed its capacity and overflow, largely untreated, into the Pacific Ocean. Such combined sewer overflows (CSOs), which typically contain high levels of pollutants, are subject to additional scrutiny under the NPDES program, and permitted municipalities with combined sewer systems must implement extensive control measures and develop a long-term control plan (LTCP) to control CSOs.
In 2019, EPA and the Regional Water Board reissued the city’s NPDES permit for its treatment facility. In addition to numeric effluent limitations—which specify maximum concentrations or loading of pollutants known to be of concern—the permit contained two non-numeric “narrative” conditions, providing that the city’s discharge shall not “cause or contribute to a violation of any applicable [state or federal] water quality standard,” nor “create pollution, contamination or nuisance” as defined by California code. The city challenged these narrative permit conditions as too vague. The city argued, among other things, that the conditions are unlawful and the Supreme Court granted certiorari on May 28, 2024,for the following reasons:
- EPA failed to meet its CWA obligation to specify the pollutant limits or operational requirements that will achieve compliance with water quality standards (WQS).
- EPA failed to follow its own rules for setting numeric effluent limits based on WQS.
The Ninth Circuit Court of Appeals rejected these arguments and upheld the permit, City and County of San Francisco v S. Environmental Protection Agency, 75 F.4th 1074 (9th Cir. 2023).
The Supreme Court’s Decision
The Supreme Court’s analysis focused on the interpretation of 33 USC § 1311(b)(1)(C), which requires EPA and implementing state agencies to impose upon NPDES permittees, in addition to federal technology-based effluent limitations (TBELs):
"any more stringent limitation, including those necessary to meet water quality standards, treatment standards, or schedules of compliance, established pursuant to any State law or regulations…or any other Federal law or regulation, or required to implement any applicable water quality standard established pursuant to this chapter."
This section generally requires NPDES permits to include limitations based upon state water quality standards, when TBELs are insufficient to ensure the receiving water will meet applicable water quality standards. Under EPA regulations, if there is a “reasonable potential” that a discharger’s effluent will cause or contribute to a violation of a WQS in the receiving water, then a permit limitation is required for the relevant pollutant. 40 CFR 122.44(d)(1)(i).
Justice Alito, writing for the majority, rejected San Francisco’s argument that “any more stringent limitation” under section 1311(b)(1)(C) refers only to effluent limitations. There was no reasonable basis for assuming, Justice Alito opined, that Congress mistakenly omitted “effluent” from the phrase “any more stringent limitation”; rather, Congress envisioned a broader concept of “limitation.” Plus, the city’s proposed narrow interpretation would exclude widely used “narrative” NPDES permit conditions, which are non-numeric directives requiring permittees to, e.g., follow “best management practices” (BMPs) to reduce pollutants in their effluent. Justice Alito noted that while narrative permit provisions do not fit easily within the definition of an “effluent limitation,” 33 U.S.C. § 1362(11), their validity was not disputed. See 40 CFR 122.44(k)(authorizing the use of BMPs in NPDES permits place of numeric effluent limitations, in certain circumstances).
However, Justice Alito agreed with San Francisco’s second, alternative argument that even if Section 1311(b)(1)(C) is broader than just effluent limitations, it nonetheless does not authorize EPA to impose NPDES permit requirements that “condition permitholders’ compliance on whether receiving waters meet applicable water quality standards.” The court referred to these types of conditions as “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.”
To support this position, Justice Alito looked first to the language of Section 1311(b)(1)(C), which requires EPA or an authorized state agency to impose permit limitations “necessary to meet” or “required to implement” any applicable water quality standard. The most natural reading, he concluded, is that this authorizes EPA to set rules that a permittee must follow in order to achieve the water quality standards, not to simply require permittees to ensure the standards are met.
This position was supported by dictionary definition of “limitation,” Justice Alito held, as referencing a restriction imposed “from without,” e.g., EPA detailing the specific steps an NPDES permittee must take to ensure the water quality standards in the receiving water will be met. However, when a permit provision “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 restraint is the plan that the permittee imposes on itself for the purpose of avoiding future liability.” In this case, the restriction comes “from within” and thus does not fall within the meaning of “limitation.”
Justice Alito also noted that the legislative history does not support the use of end-result permit provisions. Specifically, whereas the pre-1972 Water Pollution Control Act (WPCA) contained a provision that allowed direct enforcement against a permittee if the quality of the water into which they discharged failed to meet water quality standards, i.e., an end-result provision, when Congress significantly amended the WPCA in 1972 (to create the modern-day Clean Water Act), Congress deliberately omitted such provisions. Instead, Justice Alito wrote, the CWA now imposes “direct restrictions” on polluters rather than working backward from pollution to assign responsibility; EPA’s contrary position, he held, would “undo what Congress plainly sought to achieve when it scrapped the WPCA’s backward-looking approach.”
Justice Alito next emphasized that allowing end-result permit provisions would eviscerate the CWA’s permit shield, 33 U.S.C. § 1342(k), under which a permittee is deemed to be in compliance with the CWA (and can avoid the severe penalties for violating the Act) if it follows all the terms in its permit. A permittee cannot reasonably ensure that the water receiving its discharge will meet applicable water quality standards, Justice Alito explained, because there typically are many factors out of the permittee’s control that affect the quality of a receiving water.
Finally, Justice Alito concluded that end-result provisions did not account for situations where multiple permittees discharge to the same water, making it impossible for one permittee to individually ensure the water will meet applicable standards.
Accordingly, the majority reversed the Ninth Circuit.
Justice Barrett’s Dissent
Justice Barrett, joined by Justices Sotomayor, Kagan and Jackson, wrote a partial dissent. She agreed with the majority that the interpretation of “any more stringent limitation” should not be limited to “effluent limitations.” However, she disagreed that the CWA prohibited end-result limitations. The entire function of Section 1311(b)(1)(C), she wrote, is to ensure that permitted discharges do not violate state water quality standards, so why would that broad authority not allow EPA to tell permittees that they must not cause or contribute to a violation of those same standards? Justice Barrett found the majority’s interpretation of “limitation” too narrow, noting, as an example, that an airline could impose a “limitation” on the weight of checked bags, i.e., an “end result,” even though it does not tell passengers what items to pack. As for the majority’s arguments about the CWA’s permit shield or the issue of multiple dischargers to the same water, Justice Barrett contended that these relate to the broader policy concern that it may be difficult for regulated entities to comply with end-result limitations, and they may lack adequate notice of a violation. But this is ultimately a question whether a particular end-result permit limitation is rational or arbitrary and capricious—an issue that can be challenged in court; it is not necessary to eliminate end-result limitations altogether.
Ramifications of the Supreme Court’s Decision
The primary ramification of the Supreme Court’s decision in this case is that EPA, as well as authorized state agencies such as the Minnesota Pollution Control Agency, are now precluded from including in NPDES permits the types of narrative conditions frequently found in many current NPDES permits, such as those prohibiting the permittee from creating nuisance conditions or causing or contributing to a violation of water quality standards in the receiving water body. What this will mean in practice is less clear. Being unable to use these types of conditions could result in agencies issuing less-protective permits. Conversely, if agencies take the time to develop specific steps permittees must take to protect the receiving water to the same extent as the former “end-result” limitations did, this could result in more work for the agencies and a delay in the permitting process. Finally, a benefit for permittees from not having end-result limitations may be a stronger permit shield. This is because a permit shield is only effective if the permittee is in compliance with their permit; the vagueness of some end-result permit conditions—e.g., not creating “pollution” or “nuisance” in the receiving water—can make it difficult to demonstrate compliance.
For more information, contact Jeremy Greenhouse.
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