On March 4, 2025, the Supreme Court issued its opinion in City and County of San Francisco v. Environmental Protection Agency, holding that EPA does not have the authority to issue "end-result" requirements in National Pollutant Discharge Emissions System ("NPDES") permits under the Clean Water Act ("CWA").
The CWA's NPDES framework prohibits the discharge of pollutants from point sources to any "water of the United States" unless authorized by permit.A key statutory protection is the "permit shield": if a permittee complies with its permit, it is deemed in compliance with the CWA (33 U.S.C. § 1342(k)).
At issue in this case was the City and County of San Francisco's ("San Francisco") NPDES permit for its Oceanside combined wastewater facility (mixed wastewater and stormwater). For years, the permit contained certain effluent limitations pertaining to the levels of pollutants that could be present in the material that was discharged, but in 2019, EPA added two so-called "end-result" requirements to the permit. These requirements did not set specifications for what could be discharged, but rather prohibited discharges that would violate water quality standards for the receiving water (the ocean) or otherwise pollute or contaminate it, leaving it to San Francisco to figure out how to achieve that. Specifically, the permit included the following two "end-result" requirements:
- A prohibition on any discharge that would "cause or contribute to a violation of any applicable water quality standard . . . for receiving waters."
- A statement that "neither the treatment nor the discharge of pollutants shall create pollution, contamination, or nuisance" as defined by California law.
For many years, EPA routinely included these types of "end-result" requirements in permits as a backstop to effluent limitations. In this case, San Francisco challenged these requirements as beyond EPA's authority under the CWA.
The case turned on the meaning of the term "limitation" as used in 33 U.S.C. § 1311(b)(1)(C) of the CWA. This section allows EPA to include "effluent limitations" and "any more stringent limitation" necessary to meet water quality standards in NPDES permits.
San Francisco first argued that EPA only has authority to issue effluent limitations. The Court rejected this argument, finding that Congress would not have used the language "any more stringent limitation" immediately after using the term "effluent limitations" if it intended to limit EPA's authority to only effluent limitations.
However, the Court did agree with San Francisco's alternative argument that the term "limitation" means that EPA must be the one to determine and implement standards to achieve water quality standards and cannot shift this responsibility onto permittees by prescribing only the outcome. The majority opinion pointed to three main reasons for this conclusion:
- A "limitation" is defined as a "restriction . . . imposed from without," meaning a "provision that tells a permittee that it must do certain specific things" and not an end-result requirement that puts the responsibility to figure out how to achieve it on the permittee.
- The legislative history of the CWA suggests that it was Congress' intent for the CWA to impose direct restrictions on pollution rather than to work backwards from pollution to assign responsibility. Working backwards was the statutory scheme of the original version of the CWA, and Congress overhauled it in 1972 because it did not think that system was working.
- Two features of the broader statutory scheme of the CWA support this conclusion: (1) end-result requirements would negate the CWA's "permit shield," which protects permittees from liability as long as they are complying with their permit, even if they violate water quality standards; and (2) end-result requirements would provide no mechanism for fair allocation of responsibility when there are multiple dischargers contributing to violations of water quality standards.
In sum, the majority opinion concluded that "§1311(b)(1)(C) does not authorize the EPA to include 'end-result' provisions in NPDES permits. Determining what steps a permittee must take to ensure that water quality standards are met is the EPA's responsibility."
The dissent, on the other hand, believed that EPA had the authority to impose end-result requirements under the "any more stringent limitation" language in the statute.
Implications
This decision will impact how EPA and states with NPDES authority issue permits, compelling them to set more specific requirements and relieving permittees of the burden of figuring out how to achieve water quality standards. How this will affect the permit process is still unclear. In many instances, EPA lacks detailed information required to lay out specific effluent limitations a discharger must comply with. In the past, it has issued NPDES permits with end-result requirements to avoid delays or denials of permits. Now that this is no longer an option, as the dissent points out, this may slow down the permitting processes.
For large-scale dischargers like municipal stormwater and sewer systems, this decision may prove to be a double-edged sword. While the onus is now on EPA to set specific requirements in NPDES permits instead of leaving this to the discharger, this could cause issues in obtaining permits that would otherwise have been issued with end-result requirements. Moreover, it is unclear if the current administration's efforts to downsize EPA will affect the permit process further. Affected dischargers should keep a close eye on how the impacts of this decision develop.
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