The recent US Supreme Court decision in City and County of San Francisco v. EPA marks a transformative moment for Clean Water Act Permits. Issued on March 4, 2025, the ruling addresses the controversial “end-result” provisions in National Pollutant Discharge Elimination System (NPDES) permits. This decision redefines the responsibilities of the Environmental Protection Agency (EPA) and permit holders, directly impacting water quality regulation across the country.
The Clean Water Act (CWA) is designed to protect our nation’s water bodies—including lakes, rivers, and bays—by ensuring their water quality remains suitable for various uses. To enforce the CWA, the EPA issues NPDES permits that set precise limits on wastewater discharges.
In this case, the City and County of San Francisco challenged the inclusion of broad “end-result” provisions in its permit for the Oceanside combined wastewater treatment facility. Although the permit already contained standard effluent limitations, the additional provisions were designed to prevent discharges that might cause water quality standard violations and to prohibit actions that could lead to pollution or contamination under California law.
The Supreme Court ruled that the EPA is not authorized to include generic “end-result” provisions in NPDES permits. Instead, the EPA must develop and enforce specific compliance measures to ensure water quality standards are met. This decision clarifies that the responsibility for determining the necessary actions to achieve compliance falls solely on the EPA, not on water resource permit holders.
While the removal of “end-result” provisions may offer more clarity for water resource managers and facility operators, we will continue to track how the additional burden of designing and implementing compliance strategies impacts EPA administration of the NPDES program.
