Orange County enforces stormwater quality under two Phase I NPDES MS4 Permits issued by the Santa Ana and San Diego Regional Water Quality Control Boards. Title 9 of the OCCO (Water Quality) and the NPDES program require all construction and development projects in unincorporated areas to implement Best Management Practices (BMPs) and submit a Water Quality Management Plan (WQMP) before grading or building permits are issued.
Under the County's NPDES Stormwater Program, non-exempt projects in unincorporated Orange County must prepare and submit a project-specific Water Quality Management Plan (WQMP) describing permanent post-construction BMPs before any grading or building permit is issued. An Erosion and Sediment Control Plan (ESCP) must accompany all grading and building plan submittals. Title 9 of the OCCO governs water quality standards for the OC Flood Control District, prohibiting non-stormwater discharges to the storm drain system. The H2OC regional program coordinates compliance across all 34 co-permittees. Construction sites disturbing one acre or more must also obtain coverage under the State Construction General Permit (CGP) and file a Notice of Intent with the State Water Resources Control Board.
Violations of NPDES permit conditions can result in state-imposed penalties up to $10,000 per day per violation under the Clean Water Act. The County may issue stop-work orders, withhold grading permits, or require corrective action. Failure to implement required BMPs may result in enforcement by the Regional Water Quality Control Board.
Midway City, CA
Midway City is an unincorporated CDP in Orange County, CA, surrounded by Westminster. Because it has no city government, Orange County Codified Ordinances Ti...
Orange County, CA
Unincorporated Orange County exempts one small detached non-habitable accessory structure - a shed - per 7,200 square feet of building site area from accesso...
Orange County, CA
Carports in unincorporated Orange County are governed by Section 7-9-70.3(d) of the Codified Ordinances, which requires carports to comply with main-building...
Orange County, CA
Unincorporated Orange County allows the conversion of an existing garage, carport, or accessory structure into an accessory dwelling unit (ADU) under Section...
Orange County, CA
Unincorporated Orange County requires every pool/spa deeper than 18 inches to be enclosed by a barrier at least 60 inches (5 ft) high under California Health...
Orange County, CA
Unincorporated Orange County allows ADUs on any residentially zoned lot under OC Zoning Code (Title 7, Division 9) and California Government Code §65852.2 (A...
Side-by-side rule comparisons with other cities in Orange County.
See how other cities in Orange County handle stormwater management.
See how Midway City's stormwater management rules stack up against other locations.
Help us keep this page accurate. If you notice an error or outdated information, let us know.