San Antonio, TX
SAN ANTONIO WATER SYSTEM · Serves 2.1M people · Purchased Surface Water
This utility purchases treated water from a regional supplier. Contaminant data reflects monitoring at this utility's distribution system and may differ from regional district reports.
contaminants
detected
exceed
guidelines
PFAS
chemicals
Most concerning
HAA9
700×health limit
TraceAlso detected: Combined Radium, Trichloroacetic acid, Chloroform, Dichloroacetic acid, Lead, Nitrate, Tetrachloroethylene, Bromoform, strontium, Uranium, vanadium, 1,4-dioxane… (+34 more contaminants)
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The truth about legal limits
Legal does not equal safe.
Meeting EPA legal limits does not mean your water is safe for drinking.
We benchmark against the strictest independent health-based guidelines.
All Contaminants
44Filter by health risk
Critical findings — every contaminant in your water that exceeds the EWG health limit by 10× or more. Start here.
Filtration Analysis
Viven
Multi-stage
Activated
Carbon filter
Reverse
Osmosis only
PFAS / Forever Chemicals
Viven
99.9%Carbon
PartialRO only
YesHeavy Metals
Viven
99.9%Carbon
LimitedRO only
YesRadionuclides
Viven
99.9%Carbon
NoRO only
YesMinerals re-added
Viven
YesCarbon
NoRO only
NoContaminants in your water that Viven removes
Reserve nowFrequently asked
San Antonio water quality questions
- Is tap water in San Antonio, TX (ZIP 78221) safe to drink?
- Tap water for ZIP 78221, served by SAN ANTONIO WATER SYSTEM, has 22 contaminants detected above independent EWG health guidelines, including HAA9 at 700× the guideline. Meeting EPA legal limits does not necessarily mean water is safe — federal legal limits are often far higher than the latest health-based guidelines.
- What contaminants are in San Antonio, TX tap water?
- EPA monitoring data for ZIP 78221 shows 44 contaminants detected, including HAA9, HAA6Br, Chromium, HAA5, TTHM, Bromodichloromethane. Each detected level is compared against both EPA legal limits and the stricter EWG health guidelines.
- Does San Antonio, TX tap water have PFAS ("forever chemicals")?
- Yes — 3 PFAS compounds were detected out of 30 tested for ZIP 78221. PFAS are persistent synthetic chemicals linked to cancer, immune effects, and developmental harm, with no safe level of exposure established.
- How can I remove these contaminants from my drinking water?
- A multi-stage filtration system that combines activated carbon, reverse osmosis, and remineralization removes PFAS, heavy metals, and disinfection byproducts while restoring beneficial minerals. The Viven faucet is engineered to remove 99.9% of the contaminants found in tap water.
- Where does this San Antonio, TX water quality data come from?
- This report is built from U.S. EPA data: the Unregulated Contaminant Monitoring Rule (UCMR 3/4/5), the Six-Year Review (SYR4), the Lead and Copper Rule (LCR), and SDWIS violation records. Detected levels are compared against EPA legal limits and Environmental Working Group (EWG) health guidelines. Data last updated 2026-05-01.
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