Regulations

Congress enacted the Clean Water Act (CWA) in 1972 in response to nationwide concern over water pollution and to protect sources of drinking water. 

The Act established national programs for the prevention, reduction, and elimination of pollution in national navigable waters and ground waters. It also set standards and introduced required permits for the discharge and treatment of wastewater from industries and municipalities. The CWA has brought about significant progress in cleaning up industrial wastewater and municipal sewage -- specifically, single origins of pollution known as point sources.

With the reduction of point source pollution, it became evident that pollution from different sources over a wide, non-specific area, also known as non-point sources, was a major cause of water pollution. This is the type of pollution associated with storm water runoff. According to the Environmental Protection Agency, urban runoff is a major source of pollution for lakes and rivers. The 1987 Amendments to the CWA created provisions to address this issue.

In an effort to reduce non-point source urban runoff pollution, the NPDES Storm Water Program was developed under the Federal Water Quality Act of 1987. Phase I of NPDES was introduced in 1990, targeting facilities determined most likely to impact water quality. This program made it necessary for these facilities to obtain permit coverage under NPDES for storm water discharges. Phase I covers discharges from 10 industrial categories, construction activity disturbing 5 or more acres, and municipal separate storm sewer systems (MS4s), serving a population of at least 100,000. The Phase II rule was introduced in 1999. This program increased the number of facilities affected by the Storm Water Program. Under Phase II, MS4s serving a population of less than 100,000 and small construction sites, disturbing between 1 and 5 acres, are required to obtain permit coverage for storm water discharges.