County Begins In-House Testing Of Wastewater For Illness Trends

SAN DIEGO, CA — San Diego County's public health lab Wednesday began in-house wastewater testing for diseases circulating through the community, with the results published on an online public dashboard.

Sewage water samples are collected for testing from the Point Loma Wastewater Treatment Plant, South Bay Water Reclamation Plant and the Encina Wastewater Authority and allow public health officials to track trends in illness as they happen.

This type of testing began regionally during the coronavirus pandemic with SEARCH (San Diego Epidemiology and Research for COVID Health), a county-supported partnership with Scripps Research and UC San Diego.

Federal funding for SEARCH ended in December 2025, but with the May 2025 opening of the county's Public Health Lab, specialists began the training and equipment certification necessary for wastewater testing, according to a county statement.

"Bringing wastewater testing in-house with our new lab is just one example of the county's expanded ability to protect the public's health and act quickly to confront emerging disease outbreaks," said Dr. Sayone Thihalolipavan, county public health officer.

When people are sick with illnesses such as influenza or COVID-19, they shed the viruses or bacteria when they use the bathroom, shower, wash hands or do laundry.

County public health workers are looking specifically for COVID-19 (SARS-CoV-2), Influenza A and B, and respiratory syncytial virus or RSV. Scientists can also use genomic sequencing to figure out what specific strains of COVID are circulating.

The county seeks to expand testing to prioritized diseases in the future.

According to the county, wastewater data provides "non-invasive and anonymous information about the health of our community, including for those who are sick but may not yet have any symptoms."

Paired with other surveillance data, officials can make decisions about when and where to use public health tools, health messaging and recommendations for the public, and alerting local health partners.

The dashboard is located at sandiegocounty.gov/content/sdc/hhsa/programs/phs/phs_laboratory/WastewaterDashboard/.

— City New Service