This lawsuit was legally complex — and a little ironic for one of America's most environmentally progressive cities. Here's the core dispute:

SF has a permit from the EPA that allows it to discharge treated wastewater into the Bay and Ocean. The dispute began when the agency included contested provisions in San Francisco's Bayside Permit renewal in 2013 and later added them to the city's Oceanside Permit in 2019, prompting the lawsuit. SFist

These contested provisions were what's called "end-result" requirements. In plain terms, the EPA's permit language said SF couldn't discharge anything that contributed to violations of water quality standards in the receiving waters — meaning the Bay or the Ocean — not just what came out of SF's own pipes. San Francisco argued that these provisions are too vague and put the city in a difficult position, leaving it vulnerable to private lawsuits and continual enforcement action by the EPA. Wikipedia As the SFPUC general manager put it, the EPA was essentially saying "you can't pollute too much, but we won't tell you what too much is until after you've already done it."

The financial stakes were enormous. San Francisco was facing the prospect of at least $10 billion in capital expenditures, expected annual utility rates of nearly $9,000 per ratepayer — a ten-fold increase from today's average yearly bills of $851. Smart Water Magazine

SF's key argument was: we can control what comes out of our pipes, but we can't control the overall water quality of the Pacific Ocean or the Bay, since many other sources discharge into those waters too. The EPA countered that the language was clear enough and that these broad standards are necessary tools for protecting water quality.

The case went all the way to the Supreme Court, which ruled 5-4 in San Francisco's favor on March 4, 2025. The Court held that the Clean Water Act allows the EPA to issue water quality permits that contain limits only on a permit holder's discharges — which they can control — and not permits that make permit holders responsible for the overall quality of the receiving water, which they cannot control. San Francisco Water Power Sewer

The controversy: While SF won, environmentalists were alarmed. Critics warned that the ruling could set a playbook for other polluters and could stymie the EPA's ability to implement the Clean Water Act, a bedrock environmental law that has kept water safe for the last 50 years. San Francisco Water Power Sewer In an odd twist, the lawsuit drew support from fossil fuel industry groups, and some city officials were surprised to hear that SF had sued the EPA at all — including some who were hoping the city would lose. Oyez