Supreme Court Strikes Down ‘End Result’ Discharge Limitations in CWA’s NPDES Permit System

In San Francisco v. EPA, released March 4^th 2025, the United States Supreme Court ruled that Section 1311(b(1)(C) of the Clean Water Act (CWA) does not allow the U.S. Environmental Protection Agency (EPA) to include ‘end result’ provisions in National Pollutant Discharge Elimination System (NPDES) permits, which had been used to regulate San Franciso’s combined sewer and stormwater system. (Click here to read the opinion). San Francisco’s permit prohibited any discharge that “contributes to a violation of any applicable water quality standard” or create any discharge that “creates pollution, contamination, or nuisance” under California law.

San Francisco had argued that all “limitations” imposed under Section 1311 must be “effluent limitations,” but the USSC did not agree. Instead, a 5-justice majority found merit in the San Francisco’s secondary argument, that Section 1311 does not allow a permit restriction to be contingent on the quality of the water that receives the discharge. The Court found that the history of the CWA supports this conclusion, because Congress had removed a similar backward-looking structure in 1972 that required the EPA to determine which point source had caused a violation after-the-fact. The Court described ‘end result’ restrictions as an unfair burden-shift from the EPA, who implements the law, onto the permit holder, who is responsible only for his own discharge and not the entire body of water. The Court also justified this interpretation by noting that the ‘permit shield’ of the CWA would be worthless if a permit holder could be found in violation simply because a body of water, which can have many point sources, fails to meet standards. The Court notes that not all “narrative limitation” in permits are ruled out; only those which are conditioned on the ‘end result’ of receiving water.

Four Justices in Dissent noted that the CWA allows “any” limitation apart from “effluent limitation” and that this broad word would allow an ‘end result’ based restriction. They concluded that a permit limitation might be vague or unreasonable, and thus subject to challenge, but that the CWA itself would allow an ‘end result’ based limitation as falling under the plain meaning of “any.” They criticize the Court for re-drawing the meaning of the word ‘limitation’ to mean a ‘restriction from without’ instead of an internal restriction, which is contemplated by the CWA’s phased planning and implementation process.

This ruling is likely to have an impact on ‘general permit’ holders, who might now be subject to more specific narrative restrictions in future EPA permits. Smaller businesses who hold permits may need greater technical and legal support in the future when seeking new or updated NPDES permits.