Contra Costa County Watershed Program


The County Watershed Program (CWP) is responsible for ensuring that the County complies with its municipal stormwater National Pollutant Discharge Elimination System (NPDES) permits. The NPDES program is mandated by the Federal Clean Water Act, and administered in California by the State Water Resources Control Board and the Regional Water Quality Control Boards on behalf of the U.S. Environmental Protection Agency (USEPA).

Riverside Ditch, Bay Point

The NPDES program requires that all point sources that discharge into waters of the United States, including municipalities' storm drain systems, obtain a permit. The County's storm drain system collects water from numerous non-point sources of pollution, and is permitted as a MS4 (Municipal Separate Storm Sewer System) NPDES permit. The County complies with the requirements of its NPDES permit by implementing various stormwater pollution prevention activities in the unincorporated areas of Contra Costa County, including:

  • Ensuring pollutants stay out of the storm drain system, creeks, the Delta, and the Bay so that only "Rain [Goes] Down the Drain"
  • Managing and enforcing our stormwater compliance program and Enforcement Response Plan County Watershed Program Logo with Red-winged Blackbird on Cattailsto minimize stormwater impacts
  • Requiring new development projects mitigate impacts to stormwater quality and flow rates
  • Promoting pollution prevention awareness
  • Educating and outreaching to the public
  • Supporting local non-profit creek groups
  • Inspecting businesses to ensure responsible stormwater-related practices
  • Investigating and responding to illicit discharges
  • Sweeping streets to remove pollutants before they enter the storm drain system

CWP's current NPDES permits are the Municipal Regional Permit (MRP) for discharges to the San Francisco Bay (Region 2); and the East Contra Costa County Permit for discharges to the Delta (Region 5). The MRP was adopted on October 14, 2009, and applies to 76 Bay Area municipalities in order to standardize requirements, pool resources and achieve results on a large scale.

The East County Permit was adopted on September 23, 2010 and applies to the Cities of Antioch, Oakley, Brentwood, unincorporated Contra Costa County and the Contra Costa County Flood Control District. The East County Permit largely mimics the MRP. Some of our new requirements are:

  • MS4 collection system screening
  • Pump station monitoring for dissolved oxygen, conducting post-storm inspections, and trash removal
  • More public outreach and citizen involvement events
  • Increased levels of water quality monitoring
  • Focus on trash reduction, including conducting annual trash assessments/clean-ups of hot spots, and installing full trash capture units in the MS4 system, with the goal of reducing trash to County creeks by 40% by 2014, 70% by 2017, and no trash reaching creeks from our MS4 system by 2022.

CWP is also responsible for implementing certain provisions of the MRP on behalf of the Contra Costa County Flood Control and Water Conservation District (FCD). The FCD is responsible for maintaining drainage areas throughout Contra Costa County.

CWP's authority is supported by the Contra Costa County Ordinance 96-21, Title 1014 - Stormwater Management and Discharge Control (PDF).

Contact Us

  1. 255 Glacier Drive
    Martinez, CA 94553
    Phone: (925) 313-2000
    Fax: (925) 313-2333

    Office Hours

    Monday - Thursday
    7:00AM to 5:00PM
    7:00AM to 4:00PM
    Closed 12:00PM to 1:00PM