Wet-weather sampling initiated to look for sewer biofilm in San Diego watershed

SCCWRP and its partners have launched an initial round of wet-weather sampling in the San Diego River watershed  to investigate whether the microbial community that grows inside nearby sewer pipes – known as biofilm – can be found in stormwater runoff making its way to the river and its tributaries.

The wet-weather investigation, which will kick off January 31, is the latest step in an ongoing study intended to shed light on whether leaking sewer pipes could be responsible for the human fecal contamination that is widespread in Southern California urban waterways in wet weather.

Dry-weather sampling of runoff and sewer pipes last year showed that the biofilm inside sanitary sewer pipes is unique and distinct from the biofilm community inside storm drain pipes. Dry weather sampling in sewer pipes is ongoing.

Researchers hope to use these insights to determine whether human fecal contamination in waterways is coming from sewer pipes or from other sources, such as privately maintained lateral lines and septic tanks, and/or direct deposition into waterways.