NPDES logoCalifornia Water Boards

What Is NPDES ?

The federal Clean Water Act created the National Pollutant Discharge Elimination System permit program in 1987.  NPDES controls the discharge of pollutants into the Waters of the United States.  Discharges from sewage treatment plants and storm water runoff into storm drain systems (e.g., catch basins, ditches,  creaks), rivers, lakes, ground water basins, and estuaries are regulated.  Rain, snow, and ice melt run-off from agricultural land and impervious surfaces (e,g., rooftops, hardscape, streets, parking lots) carry pollutants such as oil, pesticides, herbicides, manure, sediment, trash, bacteria and heavy metals, which are the leading cause of water quality impairments in California.

How Is NPDES Enforced ?

In California, Titles 23 and 27 of the Code of Regulations authorizes the 9 Regional Water Quality Control Boards to issue general Municipal Regional permits in urbanized areas and individual permits to pretreat storm water discharge.  Temporary and permanent Best Management Practices are used to detain and remove pollutants carried by rainwater from agricultural land, construction sites, and completed buildings.  These methods include:

  • silt fences
  • sediment ponds
  • mechanical filters
  • pervious pavements
  • bio-filtration (landscaping)

California’s Porter-Cologne Water Quality Control Act also requires anyone discharging waste that could affect the quality of state waters, such as feedlots, dairies, orchards, and timber harvesting, to be permitted by the Regional Water Quality Boards.

What Are NPDES Design Standards ?

The Water Boards do not publish design standards.  Local permitted agencies, technical organizations, engineering firms, and CalTrans have develop design guidelines and standard plans for implementing Water Board regulations, many of which are available from BUILDING in CALIFORNIA.

Check the Links below for additional information.



State Water Resources Control Board

California Storm Water Quality Association

Regional Water Quality Control Board

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