The Clean Water Act (“CWA”) prohibits “discharge of any pollutant by any person” into the water of the United States without a National Pollutant Discharge Permit (“NPDES”). Puget Soundkeeper All. v. Port of Tacoma, 104 F.4th 95,95 (9th Cir. 2024). While the Environmental Protection Agency (“EPA”) has the authority to issue regulations implementing the CWA and NPDES permits, Congress authorized the EPA to delegate the power to the state, which it has done in almost all states. Id at 100.

The CWA creates a floor that the states must comply with. However, states have the authority to create regulations that raise that floor and issue NPDES under EPA-delegated authority, provided they still comply with the CWA requirements. Atl. States Legal Found. v. Eastman Kodak Co., 12 F.3d 353, 359 (2d Cir. 1993). Section 505 of the CWA allows citizens' suits for enforcement of NPDES permit violations. How far this power extends is where the circuit split lies.