Solano County, California: drinking water report. Solano County sits between the San Francisco Bay Area and Sacramento, with about 453,000 residents in…
Solano County sits between the San Francisco Bay Area and Sacramento, with about 453,000 residents in cities including Vallejo, Fairfield, and Vacaville. Travis Air Force Base – the largest Air Force base on the West Coast – occupies a significant portion of the county. Water comes from a mix of sources including the Solano Project (Lake Berryessa), the North Bay Aqueduct, and local groundwater.
Travis AFB is one of the most significant PFAS contamination sites in California. According to the Air Force's 2024 environmental investigation, PFAS from decades of AFFF use has contaminated groundwater beneath and surrounding the base. PFOS concentrations exceeding 400 ppt have been documented in monitoring wells near the fire training areas – 100 times the federal MCL of 4 ppt.
The contamination plume extends off-base into surrounding residential areas. California's State Water Board 2024 PFAS order required enhanced monitoring for public water systems in the Fairfield-Suisun area. A 2024 investigation found PFAS in two community water systems serving neighborhoods adjacent to the base.
Solano County's PFAS situation is concentrated around Travis AFB, with the highest exposure risk for residents in the Fairfield and Suisun City areas near the base. The Air Force has been conducting residential well testing, but if you have not been contacted, you can request testing through the base's environmental office.
Check your water for the latest data at your address. For PFAS at the concentrations found near Travis, reverse osmosis provides the highest removal rate available at the household level. Our water filter guide covers systems with certified PFAS performance. Get your detailed report for trends, and visit our California page for statewide data.
Drinking water is one exposure route. These federal datasets also cover Solano County, CA.
The EPA places Solano County, CA in Zone 3 - the EPA's lowest-risk category, with a predicted average indoor radon level below 2 pCi/L. Zone maps predict an area's radon potential from geology and existing indoor readings; they say nothing about a specific house. Testing is the only way to know your own level.
46% of homes in Solano County, CA were built before 1980, and 9% before 1950. Residential lead paint was banned in 1978, so housing age is the strongest available proxy for lead-paint exposure. This describes the county's housing stock, not any one home.
Modelled annual fine-particle pollution (PM2.5) in Solano County, CA averages 7.8 µg/m³, within the EPA's annual standard of 9 µg/m³. These are CDC modelled county estimates rather than readings from a specific monitor.
How radon zones work · Air quality by county · Lead exposure guide
24 public water systems serving Solano County, CA have EPA lead testing on record. The reported lead sample skews toward systems that already flagged a problem, so its exceedance rate is not directly comparable with other areas. 10 water systems serving Solano County, CA carry a health-based EPA Safe Drinking Water Act violation.
| Most-cited violation type | Systems affected |
|---|---|
| Total Trihalomethanes (TTHM) | 5 |
| Lead and Copper Rule Revisions | 3 |
| Total Coliform Rule | 2 |
| Haloacetic Acids (HAA5) | 2 |
| Surface Water Treatment Rule | 2 |
Source: EPA Lead and Copper Rule 90th-percentile tap sampling and EPA SDWIS Safe Drinking Water Act enforcement records, aggregated from the public water systems serving this county. Figures are counts of water systems, not a test of any individual home or tap.