Regulatory Background
The California State Water Resource Control Board and the nine Regional Water Quality Control Board (RWQCB), through the Clean Water Act, help address water pollution by regulating point sources that discharge pollutants, such as stormwater and non-stormwater discharges, to waters of the United States under the National Pollutant Discharge Elimination System (NPDES) Permitting Program. Orange County is located within the Santa Ana and San Diego RWQCB regions:
- Santa Ana RWQCBexplore covers North Orange County, which includes central Orange County. The County of Orange, Orange County Flood Control District (OCFCD), and the 26 cities of North Orange County are regulated by a Phase I MS4 Permit issued by the Santa Ana RWQCB.
-
- San Diego RWQCBexplore covers South Orange County. The County of Orange, OCFCD, and the 10 cities of South Orange County (south of El Toro Road) are regulated by a Phase I Regional MS4 Permit issued by the San Diego RWQCB.
These MS4 Permits require the development of stormwater program(s) that aim to (1) effectively prohibit non-stormwater discharges into the storm drain system and (2) reduce the discharge of pollutants to the maximum extent practicable through the implementation of best management practices (BMPs) and other control strategies. These permits incorporate Total Maximum Daily Loads (TMDL), which set limits on pollutants discharged into water bodies to protect their beneficial uses. TMDLs applicable to North Orange County can be found on the Santa Ana RWQCB’s websiteand TMDLs applicable to South Orange County can be found on the San Diego RWQCB’s website.
H2OC Stormwater Program
While each Permittee has a plan outlining the strategies and activities they will implement to comply with MS4 Permit requirements, “H2OC” serves as the cooperative stormwater program, which includes all Orange County MS4 Permittees. As the “Principal Permittee” on both Santa Ana Region and San Diego Region MS4 Permits, the County guides development and implementation of the H2OC Stormwater Program, collaborating with Permittees to ensure compliance and prevent pollution in our waterways.
