Summary

In a 5-4 decision, the US Supreme Court weakened the Clean Water Act by limiting the EPA’s authority to issue generic water quality standards.

The majority, led by Justice Alito, ruled that the EPA must impose specific pollutant limits instead of broad, “end result” requirements. The city of San Francisco prevailed, challenging the EPA’s narrative-based permits for sewage discharges.

Dissenters, led by Justice Barrett, argued the law authorizes stronger measures to protect water supplies.

The case marks the first significant Clean Water Act challenge since Chevron deference was overturned in 2024.