In the closely watched case, City and County of San Francisco v. Environmental Protection Agency, the Supreme Court held in a 5-4 decision that Section 1311(b)(1)(C) of the Clean Water Act (CWA) does not authorize the Environmental Protection Agency (EPA) to condition compliance with its National Pollutant Discharge Elimination System (NPDES) permits on the quality of the receiving waters. The ruling is expected to significantly impact wastewater treatment facilities nationwide by narrowing the scope of EPA enforcement authority.