Post Construction

Post-construction storm water management in areas undergoing new development or redevelopment is necessary because runoff from these areas have been shown to significantly affect receiving waterbodies. Many studies indicate that prior planning and design for the minimization of pollutants in post-construction storm water discharges is the most cost-effective approach to storm water quality management. 

Municipal Separate Storm Sewer Systems (MS4) Permit

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


As an MS4 operator, the City of Yorba Linda must implement the requirements of the National Pollution Discharge Elimination System (NPDES) permits for the Santa Ana Regional Water Quality Control Board (SARWQCB) region. The Orange County Stormwater Program is a cooperative of the County of Orange, Orange County Flood Control District (OCFCD) and all 34 Orange County cities. In May and December, 2009, the SARWQCB adopted the Fourth Term NPDES permits (PDF).