Chapter 5 – Clean Water Act: Major Progress but Persistent Challenges


The Clean Water Act (CWA) regulates discharges into rivers, streams, and other waterbodies through a structure of industry-specific, technology-based effluent limitations, although states also retain authority to set water quality standards. The CWA sets up a National Pollution Discharge Elimination System (NPDES) mandating permits for any point source emissions into surface waters. Pollution discharges must also comply with effluent limitations and state water quality standards. Once a discharger has reduced its pollution, it may not go back to releasing more pollution under an anti-backsliding provision. New sources must comply with best available technology (BAT) standards. Federal financial support to communities to build publicly owned sewage treatment plants (POTWs) is one of the success stories of the CWA. For non-point pollution, EPA created a watershed approach using total maximum daily loads (TMDLs) and NPDES permits. The CWA regulates discharge of dredged of fill materials in navigable waters and adjacent wetlands.