The Clean Water Act (CWA), codified at 33 U.S.C. Chapter 26, is the cornerstone of surface water quality protection in the United States. The act establishes the basic structure for regulating discharges of pollutants into the 'waters of the United States' and for regulating quality standards for those waters. It was enacted in 1972 as a major overhaul of the Federal Water Pollution Control Act of 1948.