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The National Pollutant Discharge Elimination System (NPDES) was originally created as an amendment to the Clean Water Act (CWA) in 1972 and established a permit program to control water pollution by regulating the discharge of pollutants into waters of the United States. Initially, NPDES permits focused on regulating point source pollution which originates from a definite source, such as industrial facilities, and discharges at a specific point. In the early 1970s, only one-third of the nation’s waters were considered safe for fishing and swimming. Through the advancement of CWA and NPDES, two-thirds of the nation’s waters were considered safe by the mid-1990s. In 1987, an amendment to the CWA directed the NPDES program to address non-point source (NPS) pollution through a phased approach. NPS pollution does not have a specific origin or discharge location but is considered to be general surface runoff containing pollutants from streets, parking lots, construction sites, homes, businesses and many other sources. Phase I of the NPDES permit program began in 1990 and applied to construction sites disturbing 5 or more acres of soil and municipalities with populations equal to 100,000 or more. Phase II of the NPDES permit program became effective on March 10, 2003 and applied to construction sites disturbing between 1 and 5 acres of soil and municipalities with populations between 10,000 and 100,000. NPDES is a federally mandated program that is implemented and enforced locally. Currently, all construction sites disturbing 1 or more acres of soil must obtain an NPDES General Permit from the State Water Resources Control Board (SWRCB). The County of Sonoma has obtained Municipal Separate Storm Sewer System (MS4) permits from the North Coast Regional Water Quality Control Board (NC RWQCB) and the San Francisco Bay Regional Water Quality Control Board (SFB RWQCB). For further information regarding SUSUMP, refer to PRMD website resource: http://www.sonoma-county.org/prmd/sw/sw-npdes.htm.