Federal and county health workers will knock on doors in the Tijuana River Valley starting Thursday, Sept. 17, to ask residents how Tijuana River sewage pollution is affecting their health.

The Centers for Disease Control and Prevention and San Diego County announced Sept. 9 that they will conduct a second Community Assessment for Public Health Emergency Response (CASPER) survey. The effort follows a 2024 survey that documented widespread symptoms among South Bay households. Bilingual teams wearing badges and reflective vests will visit randomly selected homes for 20-minute interviews in English or Spanish, The Coronado News reported.

Participation is voluntary and anonymous.

When and where

Survey teams will visit homes from 2 p.m. to 7 p.m. on Thursday, Sept. 17, and Friday, Sept. 18, and from 10 a.m. to 7 p.m. on Saturday, Sept. 19. The county has not specified which neighborhoods or streets teams will cover, saying only that they will canvass the Tijuana River Valley.

What the first survey found

The 2024 CASPER survey found that affected households reported headaches, nausea, cough and throat irritation. The survey also found many households reported declining quality of life and were taking steps to avoid contaminated areas. The county said those findings helped build the case for more state and federal funding.

Dr. Sayone Thihalolipavan, the county's public health officer, said the new round will target a fresh sample of families. "By comparing this assessment to the one from 2024, we can better identify what is working and what more needs to be done to support our South Bay neighbors," Thihalolipavan said.

Pollution by the numbers

The survey comes as the sewage crisis continues to worsen. Some South Bay beaches have been closed for more than 1,400 consecutive days. UCSD Scripps researchers have attributed roughly 34,000 illnesses annually to water pollution in Imperial Beach, and hydrogen sulfide levels in the air have been measured at 16 times the state standard, according to a Coronado Times report on the county's $5.8 million infrastructure funding vote Sept. 1.

District 1 Supervisor Paloma Aguirre, chair pro tempore of the San Diego County Board of Supervisors, encouraged residents to participate. She said the county and its federal partners need firsthand accounts to guide their response to the pollution.

The county has not announced when results from the second survey will be released. More information is available at sandiegocounty.gov/southregionhealth.