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Pacific Southwest, Region 9

Serving: Arizona, California, Hawaii, Nevada, Pacific Islands, Tribal Nations

Nonpoint Source Pollution

Nonpoint Source Pollution Quick Finder
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Tidal lagoon restored beneath Golden Gate Bridge in San Francisco
Restored tidal lagoon at Crissy Field San Francisco, Calif.

Nonpoint source (NPS) pollution, or polluted runoff, is the major source and cause of water quality impairment for waters on the state water quality limited segment lists required under CWA 303(d). Polluted runoff occurs when rain, snowmelt, irrigation water, and other water sources move across and through land, picking up pollutants and carrying them into lakes, rivers, wetlands, coastal waters and underground sources of drinking water. Taking a watershed approach to environmental issues provides an excellent opportunity for communities and agencies to work together to achieve water quality improvements.

See the national EPA Non Point Source page for more background on polluted runoff.

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