Clean Water Act
Text extracted from http://www.epa.gov/region5/defs/html/cwa.htm
The Clean Water Act is a 1977 amendment to the Federal Water Pollution Control Act of 1972, which set the basic structure for regulating discharges of pollutants to waters of the United States.
The law gave EPA the authority to set effluent standards on an industry basis (technology-based) and continued the requirements to set water quality standards for all contaminants in surface waters. The CWA makes it unlawful for any person to discharge any pollutant from a point source into navigable waters unless a permit (NPDES) is obtained under the Act.
The 1977 amendments focused on toxic pollutants. In 1987, the CWA was reauthorized and again focused on toxic substances, authorized citizen suit provisions, and funded sewage treatment plants (POTW's) under the Construction Grants Program.
The CWA provisions for the delegation by EPA of many permitting, administrative, and enforcement aspects of the law to state governments. In states with the authority to implement CWA programs, EPA still retains oversight responsibilities.
A brief history of the Clean Water Act in its first 25 years on EPA web site
The Clean Water Act in Pennsylvania, a summary by the River Network
The History of the Clean Water Act on the Natural Resources Defense Council web site.
For an overview of the federal government's role in the Protection and Management of Water Resources see the North American Commission for Environmental Cooperation (CEC).