During a routine survey of Mission Creek at the concrete channel near Carrillo Street, Creeks Division staff noticed what appeared to be degraded toilet paper and brown sludge in water flowing from the storm drain that runs along West Carrillo Street.
Extremely high indicator bacteria levels, in addition to sporadic positive test results for human sewage markers during our DNA-based research efforts suggested that human waste was entering the storm drain. But where, and how?
Previous testing of water samples upstream in the storm drain network, along with televising part of the storm drain several years ago, did not reveal the source. Could it be occasional RV dumping, an intermittent sewage leak, or even people defecating near parking lot drains?
With a combination of persistence and teamwork, the Creeks Division and Wastewater Division identified two sources of untreated sewage entering the storm drain from compromised private sanitary sewer laterals.
PHOTO: Dye testing revealed that private sewer laterals were leaking into the storm drain system, which flows from the Carrillo Drain into Mission Creek..
The first source was comprised of untreated sewage from a commercial building, where a broken private lateral crossed through the top of the brick and mortar roof of the storm drain. The second, a much slower leak, came from a failing private lateral serving another commercial building.
Within 24 hours of confirming the sources of the leaks, contractors hired by the property owners had repaired the broken sewer laterals.
Click here for additional details on how this mystery was solved.
Remember, if you see (or smell) pollution in the street, storm drain, or creek, call the Creeks Division's Enforcement Hotline at (805) 897-2688.