2025 Supreme Court Environmental Decisions Recap: Limiting EPA's Use of "End-Result" Provisions in NPDES Permits

As we look ahead to 2026, we're sharing a series of blog posts recapping some of the most damaging U.S. Supreme Court decisions that will shape our ability to protect the environment for decades to come. (Blog 4/4)

Supreme Court Limits EPA's Use of "End-Result" Provisions in NPDES Permits

In City & County of San Francisco v. EPA, 145 S. Ct. 704 (2025) , the Supreme Court struck down certain narrative (as opposed to numeric) standards that the Environmental Protection Agency (EPA) had included in San Francisco's National Pollutant Discharge Elimination System (NPDES) permit under the Clean Water Act (CWA).

NPDES permits are required for discharges of pollutants from a point source into waters of the United States. In this case, San Francisco's wastewater treatment plant operated under a permit issued by the EPA.

Typically, an NPDES permit specifies discharge limits or treatment requirements, which may be numeric (e.g., pH levels) or narrative (e.g., "no visible sheen"). If the permit holder complies with those requirements, the Clean Water Act's "permit shield" provision deems them in compliance with the Act. This framework provides regulatory certainty: following the permit's explicit terms should protect the permittee from additional liability.

However, in 2019, the EPA added two provisions to San Francisco's wastewater treatment permit that imposed liability if the receiving waters failed to meet certain water quality standards - regardless of whether the City had met all other permit conditions. One provision prohibited any discharge that "contributes to" a violation of applicable water quality standards. The other prohibited any discharge that "creates pollution, contamination, or nuisance" under California law. These types of provisions are quite common in NPDES permits and can provide flexibility by allowing permittees to determine the most cost-effective way to comply.

The Court invalidated these provisions, coining the term "end-result provisions" to describe them. It held that the Clean Water Act authorizes the EPA to impose limitations within a permittee's control - such as limits on the facility's own discharges - but not broad requirements tied to downstream water quality conditions influenced by multiple sources. By requiring San Francisco to ensure downstream water quality regardless of other pollution contributors, the Court concluded that the EPA exceeded its statutory authority. This decision removes a longstanding tool from the EPA's regulatory toolbox and will likely make it harder to keep our waters clean.

This case also illustrates how Loper Bright Enterprises v. Raimondo continues to reshape judicial review of agency actions. In Loper Bright , the Court ended the Chevron doctrine, under which courts deferred to an agency's reasonable interpretation of ambiguous statutes. Now, judges independently interpret statutory meaning.

Here, the Court analyzed the Clean Water Act and concluded that Congress empowered the EPA to regulate only a permittee's own discharges - not to hold it responsible for the condition of the water body as a whole. Under Chevron , the Court would have asked whether the EPA's interpretation of the statute was reasonable and, if so, deferred to the agency's judgment. Under Loper Bright , however, the Court claimed the final authority to determine how the EPA and other agencies may fulfill their statutory mandates. In this case, that meant concluding that the EPA's long-used "end-result provisions" are not authorized.

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