Tap water and home risks
Is San Antonio tap water safe?
San Antonio's main water supplier is San Antonio Water System, serving about 2,643,729 people from surface water (rivers, lakes, reservoirs). Here is what EPA's public records show, as of October 2026.
PFAS results
San Antonio Water System was tested for 29 PFAS compounds between May 2023 and June 2026. 3 were detected at least once. PFOA and PFOS stayed at or below EPA's 4 ng/L limit.
| Compound | Highest result | EPA limit | Detected |
|---|---|---|---|
| PFOS | not detected | 4 ng/L | 0 of 91 samples |
| PFOA | not detected | 4 ng/L | 0 of 91 samples |
| PFBA | 9.2 ng/L | none | 3 of 91 samples |
| PFBS | 3.8 ng/L | none | 2 of 91 samples |
| PFPeA | 3.2 ng/L | none | 1 of 91 samples |
EPA's limits of 4 ng/L for PFOA and PFOS were set in 2024; utilities must meet them by April 2029 (EPA has proposed allowing some systems until 2031). These results come from EPA's UCMR 5 screening program, not compliance tests. Compounds not shown were tested and not detected.
Lead and copper
In the most recent round of home tap sampling (December 2024), 90% of samples had 1.6 ppb of lead or less. The federal action level is 15 ppb; EPA's health goal for lead is zero.
| Sampling period ended | Lead, 90th percentile |
|---|---|
| December 2024 | 1.6 ppb |
| December 2021 | 2.25 ppb |
| June 2021 | 1.7 ppb |
| December 2020 | 2.09 ppb |
| December 2017 | 3.25 ppb |
| June 2017 | 2.94 ppb |
| December 2015 | 4.08 ppb |
| December 2012 | 3.53 ppb |
The 90th percentile is the level that 90% of sampled homes were at or below. It describes the system, not your tap.
Health-based violations since 2016
EPA records no health-based violations for San Antonio Water System since January 2016. Monitoring and reporting violations, which are paperwork issues, are not counted here.
Radon in Bexar County
Bexar County is in EPA radon Zone 3 (low potential). Radon is a gas from the ground that enters homes through the foundation; the zone describes the area's potential, not your house. EPA recommends testing every home.
What you can do
- PFAS were found below EPA's limits. If you want to lower exposure anyway, a filter certified to NSF/ANSI 53 or 58 for PFAS is the tested option.
- Lead usually comes from a home's own service line and pipes, not the treatment plant. If your home was built before 1986, ask San Antonio Water System for your service line material or test your tap.
- Radon varies house to house even in low zones. EPA recommends testing every home.
Check a ZIP code
Some neighborhoods in San Antonio get water from a different system. Enter your ZIP to see the systems and county that cover it.
Other cities in Texas
Sources: EPA ECHO Safe Drinking Water Act data (2026Q3, published October 2026), EPA UCMR 5 occurrence data (August 2026), EPA Map of Radon Zones, US Census Bureau Vintage 2024 estimates. See the methodology.