San Diego Region - Sanitary Sewer System Spills

Sanitary sewer systems convey wastewater (sewage) from homes, businesses, and industries to municipal wastewater treatment plants. Sewage is untreated or partially treated domestic, municipal, commercial, and/or industrial waste and typically contains high levels of pathogens, toxicants, nutrients, and other pollutants that threaten public and environmental health. Sanitary sewer spills may pollute receiving waters, threaten beneficial uses of surface water and groundwater, and impair the recreational uses and aesthetic enjoyment of our waters.

Statewide Waste Discharge Requirements for Sanitary Sewer Systems

The State Water Resources Control Board (State Water Board) Order No. 2022-0103-DWQ, Statewide Waste Discharge Requirements General Order for Sanitary Sewer Systems (Statewide WDRs) became effective on June 5, 2023. The Statewide WDRs regulate public agencies that own/operate sanitary sewer systems greater than one mile in length, and give the Regional Water Boards discretion to regulate sanitary sewer systems of any size that are owned/operated by public agencies, federal agencies, or private entities.

The Statewide WDRs require agencies to develop and implement sewer system management plans, spill emergency response plans, and to report all sanitary sewer spills to the State Water Board’s online California Integrated Water Quality System (CIWQS) Sanitary Sewer System Database. CIWQS data is publicly accessible and can be both viewed and downloaded via the links provided below. A monthly summary of spills in the region is provided in the San Diego Water Board’s Executive Officer Reports.

San Diego Region Waste Discharge Requirements for Sanitary Sewer Systems

Sanitary sewer systems in the San Diego Region are also regulated under the San Diego Water Board’s Order No. R9-2007-0005, Waste Discharge Requirements for Sewage Collection Agencies in the San Diego Region (San Diego Region WDRs). The San Diego Region WDRs establish additional prohibitions and requirements beyond those provided in the Statewide WDRs and apply to all sewage collection agencies in the San Diego Region enrolled under the Statewide WDRs.

Online Sanitary Sewer System Spills Database

Sanitary sewer system spills are reported by sewage collection agencies to the San Diego Water Board using CIWQS, the State Water Board's regulatory and water quality information management system. The State Water Board website also includes an interactive geographic information system (GIS) mapping tools which can be used to spatially display spills reported to the CIWQS. Below are links related to the CIWQS sanitary sewer systems spills database and GIS mapping tool:

• CIWQS Help Center – Sanitary Sewer Systems
• State Board Public Reports website
• Interactive Sanitary Sewer Systems Spill Reports
• Public Sanitary Sewer Systems Incident Map
• Sanitary Sewer Overflows (SSO) Data Visualization Tool - San Diego Region

Permits and Related Documents

• Statewide WDRs (Order No. 2022-0103-DWQ)
• Statewide WDRs General Order Information Website
• San Diego Region WDRs (Order No. R9-2007-0005)
• 24-hour Report Form for Category 1 Spills (to be used if CIWQS is not working)
• Sewer System Management Plan and Program Audit Due Dates Look Up

Additional Resources

• Sewage Pollution Within the Tijuana River Watershed
• US. Environmental Protection Agency Sanitary Sewer Overflow Webpage
• California Water Environment Association (Education & Training on Managing Sanitary Sewer Systems)