OC Stormwater Program

OC Stormwater Program

The Orange County Stormwater Program (Program) is a cooperative of the County of Orange (Unincorporated OC), Orange County Flood Control District (OCFD) and all 34 Orange County cities.


Water pollution degrades surface waters, creating unsafe conditions for fishing, swimming, and other activities as well as impacting drinking water resources. Protection and preservation of water resources in the United States is governed by the federal Clean Water Act. Passage of the 1987 Water Quality Act established regulation of non-point source pollution to augment the regulation of point source pollution established by the 1972 Federal Water Pollution Control Act. Section 402(p)(2) of the 1987 regulation created the National Pollution Discharge Elimination System (NPDES) permit program to control non-point source pollution.

The Environmental Protection Agency (EPA) enforces the CWA requirements; however, in California, the State Water Resources Control Board and nine associated Regional Water Quality Control Boards ensure compliance with the CWA under the auspices of the EPA.

Since 1990, operators of municipal separate storm sewer systems (MS4s) are required to develop a stormwater management program designed to prevent harmful pollutants from impacting water resources via stormwater runoff. In Orange County, stormwater and urban runoff enter the stormwater system from streets, curbs and gutters and travel, untreated to local water bodies or the Pacific Ocean.

As an MS4 operator, Orange County must obtain and implement NPDES permits for both the Santa Ana (SAR) and San Diego (SDR) Regional Water Quality Control Board regions. As the Principal Permittee on both SAR and SDR NPDES Permits, the County guides development and implementation of the Program, collaborating regularly with Co-permittees to ensure compliance and prevent ocean pollution.  

stormwater program


The OC Stormwater Program complies with National Pollutant Discharge Elimination System (NPDES) Permits to protect water resources. The County is under the jurisdiction of both the Santa Ana Regional Water Quality Control Board (SAR; North and Central Orange County) and the San Diego Regional Water Quality Control Board (SDR; South Orange County), who issue these permits which are revised and adopted approximately every five years.  

The current Santa Ana Regional NPDES Permit, Order No. R8-2009-0030 as amended by Order No. R8-2010-0062, became effective on November 8, 2010 and is in the process of being revised by the SAR board. The San Diego Regional Water Quality Control Board (RWQCB) adopted Order R9-2013-0001 on May 8, 2013. This Order, which was amended in February of 2015 to include areas of South Orange County, requires local government, in each of the region's Watershed Management Areas (WMAs) to develop Water Quality Improvement Plans (WQIPs). To find out more information on how South Orange County MS4 Permittees are complying with the requirements of the San Diego Regional MS4 Permit, please visit southocwqip.org.