Summary data sourced from reports from the California Integrated Water Quality System (CIWQS) sanitary sewer overflow (SSO) database and were generated using the Interactive SSO Reports tool from the State Water Resources Control Board (SWRCB) Sanitary Sewer Overflow Reduction Program. Data on Category 1, 2 and 3 SSOs in LA County for the years 2013 to 2017 was used. The number and volume of spills was analyzed. For some spills, only a portion of the spill volume may have reached a waterbody. Spills were categorized as small (<1,000 gallons), minor (between 1,000 and 10,000 gallons), or major (>10,000 gallons).
See "Number and Volume of Sewage Spills to Water (2013-2017) Detailed" for more detailed data.