San Francisco v. EPA: Supreme Court Strikes Down EPA’s “End-Result” Permit Requirements

On March 4, 2025, the U.S. Supreme Court issued a 5-4 decision in City and County of San Francisco v. Environmental Protection Agency, narrowing the Environmental Protection Agency’s (EPA) authority under the Clean Water Act (CWA) to impose outcome-based permit conditions—termed “end-result” requirements by the Court—on entities discharging pollutants into U.S. waters. The majority held that the CWA does not authorize the EPA or states to enforce permit provisions that make permittees responsible for the quality of receiving waters absent specific, quantifiable effluent limitations. This decision has immediate implications for the National Pollutant Discharge Elimination System (NPDES) permitting framework, particularly regarding the enforceability of narrative water quality standards.

Legal Background

Enacted in 1972, the CWA establishes a comprehensive framework for regulating the discharge of pollutants into U.S. waters, primarily…