What was found in San Antonio's water
The level at the city's main supplier, the highest level anywhere in the city, the EPA limit for each, and where every figure comes from.
| Contaminant | Level vs EPA limit | Suppliers | Source |
|---|---|---|---|
| Fluoride | 834 µg/L 21% of the EPA limit 4000 µg/L Main supplier: SAN ANTONIO WATER SYSTEM · 2,643,729 people · 2019
Highest in the city: 7308 µg/L — JBSA RANDOLPH · 10,949 people · 2019 | 11/11 | SYR4 |
| Nitrate | 2440 µg/L 24% of the EPA limit 10000 µg/L Main supplier: SAN ANTONIO WATER SYSTEM · 2,643,729 people · 2019
Highest in the city: 2854 µg/L — THE OAKS WSC · 1,191 people · 2019 | 11/11 | SYR4 |
| Nitrate-Nitrite | 2369 µg/L 24% of the EPA limit 10000 µg/L Main supplier: SAN ANTONIO WATER SYSTEM · 2,643,729 people · 2019
Highest in the city: 2655 µg/L — THE OAKS WSC · 1,191 people · 2019 | 11/11 | SYR4 |
| Copper | 289 µg/L 22% of the EPA limit 1300 µg/L Main supplier: SAN ANTONIO WATER SYSTEM · 2,643,729 people · 2018
Highest in the city: 1487 µg/L — JBSA RANDOLPH · 10,949 people · 2019 | 11/11 | SYR4 |
| Chlorite | 939 µg/L 94% of the EPA limit 1000 µg/L Highest in the city: JBSA SAM HOUSTON · 37,563 people · 2019 | 1/11 | SYR4 |
| Barium | 115.7 µg/L 5.8% of the EPA limit 2000 µg/L Main supplier: SAN ANTONIO WATER SYSTEM · 2,643,729 people · 2019
Highest in the city: 142.25 µg/L — JBSA RANDOLPH · 10,949 people · 2017 | 11/11 | SYR4 |
| TTHM | 72.65 µg/L 91% of the EPA limit 80 µg/L Main supplier: SAN ANTONIO WATER SYSTEM · 2,643,729 people · 2019 | 10/11 | SYR4 |
| Lead | 6.178 µg/L 41% of the EPA limit 15 µg/L Main supplier: SAN ANTONIO WATER SYSTEM · 2,643,729 people · 2018
Highest in the city: 59.5 µg/L — JBSA SAM HOUSTON · 37,563 people · 2019 | 10/11 | SYR4 |
| Lithium | 25.5 µg/L No EPA limit set Main supplier: SAN ANTONIO WATER SYSTEM · 2,643,729 people · 2025
Highest in the city: 26 µg/L — JBSA RANDOLPH · 10,949 people · 2025 | 3/11 | UCMR-5 |
| Chloroform | 25.1 µg/L No EPA limit set Main supplier: SAN ANTONIO WATER SYSTEM · 2,643,729 people · 2019 | 7/11 | SYR4 |
| Bromodichloromethane | 23.8 µg/L No EPA limit set Main supplier: SAN ANTONIO WATER SYSTEM · 2,643,729 people · 2019 | 7/11 | SYR4 |
| Dibromochloromethane | 22.07 µg/L No EPA limit set Main supplier: SAN ANTONIO WATER SYSTEM · 2,643,729 people · 2019 | 10/11 | SYR4 |
| Total Haloacetic Acids (HAA5) | 18.9 µg/L 32% of the EPA limit 60 µg/L Main supplier: SAN ANTONIO WATER SYSTEM · 2,643,729 people · 2019 | 6/11 | SYR4 |
| Gross Beta Particle Activity | 11.525 pCi/L No EPA limit set Main supplier: SAN ANTONIO WATER SYSTEM · 2,643,729 people · 2019 | 1/11 | SYR4 |
| Dichloroacetic Acid | 9.8 µg/L No EPA limit set Main supplier: SAN ANTONIO WATER SYSTEM · 2,643,729 people · 2019 | 4/11 | SYR4 |
| Bromoform | 8.245 µg/L No EPA limit set Main supplier: SAN ANTONIO WATER SYSTEM · 2,643,729 people · 2019 | 8/11 | SYR4 |
| Di(2-ethylhexyl) Phthalate | 6.74 µg/L 112% of the EPA limit, at the 95th percentile of samples — 6 µg/L Main supplier: SAN ANTONIO WATER SYSTEM · 2,643,729 people · 2019 | 3/11 | SYR4 |
| Dibromoacetic Acid | 6.6 µg/L No EPA limit set Main supplier: SAN ANTONIO WATER SYSTEM · 2,643,729 people · 2019 | 6/11 | SYR4 |
| Trichloroacetic Acid | 5.6 µg/L No EPA limit set Main supplier: SAN ANTONIO WATER SYSTEM · 2,643,729 people · 2019 | 3/11 | SYR4 |
| Gross Alpha, Excl. Radon And U | 5.245 pCi/L 35% of the EPA limit 15 pCi/L Main supplier: SAN ANTONIO WATER SYSTEM · 2,643,729 people · 2019 | 4/11 | SYR4 |
| Selenium | 4.36 µg/L 8.7% of the EPA limit 50 µg/L Main supplier: SAN ANTONIO WATER SYSTEM · 2,643,729 people · 2019 | 5/11 | SYR4 |
| Xylenes, Total | 3.5555 µg/L 0% of the EPA limit 10000 µg/L Main supplier: SAN ANTONIO WATER SYSTEM · 2,643,729 people · 2019
Highest in the city: 4.2 µg/L — THE OAKS WSC · 1,191 people · 2019 | 2/11 | SYR4 |
| Chromium | 4.146 µg/L 4.1% of the EPA limit 100 µg/L Main supplier: SAN ANTONIO WATER SYSTEM · 2,643,729 people · 2019 | 2/11 | SYR4 |
| Monobromoacetic Acid | 1.775 µg/L No EPA limit set Main supplier: SAN ANTONIO WATER SYSTEM · 2,643,729 people · 2019
Highest in the city: 3.5 µg/L — CITY OF ALAMO HEIGHTS · 7,357 people · 2019 | 2/11 | SYR4 |
| Cadmium | 3.4 µg/L 68% of the EPA limit 5 µg/L Main supplier: SAN ANTONIO WATER SYSTEM · 2,643,729 people · 2019 | 1/11 | SYR4 |
| Combined Radium (-226 And -228) | 2.532 pCi/L 51% of the EPA limit 5 pCi/L Main supplier: SAN ANTONIO WATER SYSTEM · 2,643,729 people · 2019
Highest in the city: 3.37 pCi/L — JBSA RANDOLPH · 10,949 people · 2017 | 10/11 | SYR4 |
| Monochloroacetic Acid | 2.85 µg/L No EPA limit set Main supplier: SAN ANTONIO WATER SYSTEM · 2,643,729 people · 2019 | 5/11 | SYR4 |
| Combined Uranium | 1.3 µg/L 4.3% of the EPA limit 30 µg/L Main supplier: SAN ANTONIO WATER SYSTEM · 2,643,729 people · 2019
Highest in the city: 2.165 µg/L — THE OAKS WSC · 1,191 people · 2015 | 2/11 | SYR4 |
| Arsenic | 2.1 µg/L 21% of the EPA limit 10 µg/L Highest in the city: JBSA SAM HOUSTON · 37,563 people · 2019 | 2/11 | SYR4 |
| Dalapon | 1.88 µg/L 0.9% of the EPA limit 200 µg/L Highest in the city: PIONEER ESTATES · 320 people · 2019 | 1/11 | SYR4 |
| Dichloromethane | 1.27 µg/L 25% of the EPA limit 5 µg/L Main supplier: SAN ANTONIO WATER SYSTEM · 2,643,729 people · 2019 | 1/11 | SYR4 |
| Tetrachloroethylene | 0.9675 µg/L 19% of the EPA limit 5 µg/L Main supplier: SAN ANTONIO WATER SYSTEM · 2,643,729 people · 2019 | 1/11 | SYR4 |
| Ethylbenzene | 0.6920 µg/L 0.1% of the EPA limit 700 µg/L Main supplier: SAN ANTONIO WATER SYSTEM · 2,643,729 people · 2019 | 2/11 | SYR4 |
| Thallium, Total | 0.6750 µg/L 34% of the EPA limit 2 µg/L Highest in the city: PIONEER ESTATES · 320 people · 2019 | 1/11 | SYR4 |
| Atrazine | 0.4400 µg/L 15% of the EPA limit 3 µg/L Highest in the city: THE OAKS WSC · 1,191 people · 2019 | 1/11 | SYR4 |
| 2,4-D | 0.1000 µg/L 0.1% of the EPA limit 70 µg/L Main supplier: SAN ANTONIO WATER SYSTEM · 2,643,729 people · 2019 | 1/11 | SYR4 |
| Pfba | 0.0092 µg/L No EPA limit set Main supplier: SAN ANTONIO WATER SYSTEM · 2,643,729 people · 2025 | 1/11 | UCMR-5 |
| PFBS | 0.0038 µg/L No EPA limit set Main supplier: SAN ANTONIO WATER SYSTEM · 2,643,729 people · 2025 | 1/11 | UCMR-5 |
| Pfpea | 0.0032 µg/L No EPA limit set Main supplier: SAN ANTONIO WATER SYSTEM · 2,643,729 people · 2025 | 1/11 | UCMR-5 |
| Lead | 0.0016 mg/L 11% of the EPA limit 0.0150 mg/L Main supplier: SAN ANTONIO WATER SYSTEM · 2,643,729 people · 2024
Highest in the city: 0.0028 mg/L — CITY OF ALAMO HEIGHTS · 7,357 people · 2023 | 11/11 | LCR |
Each bar shows the measured level as a share of the EPA limit: green is
well under, amber is close to it, red is over. For lead and copper the
limit applies to exactly the 90th-percentile figure shown, so red there
means a real exceedance. For everything else the limit applies to a
running annual average while the figure is the 95th percentile of the
system's samples — over 100% is worth reading, but is not by itself a
violation.
Formal violations are listed separately.
These are the utilities' own EPA-reported results, not a city-wide
average. A detection means the lab measured the
substance — it isn't the same as exceeding a legal limit. Hover a source
tag to see the EPA program and years behind each figure.
Water suppliers serving San Antonio
| Supplier | Population served |
|---|---|
| SAN ANTONIO WATER SYSTEM | 2,643,729 |
| JBSA SAM HOUSTON | 37,563 |
| JBSA RANDOLPH | 10,949 |
| CITY OF ALAMO HEIGHTS | 7,357 |
| THE OAKS WSC | 1,191 |
| BLUE SKIES OF TEXAS WEST | 796 |
| PIONEER ESTATES | 320 |
| CADILLAC WATER | 252 |
| LITTLE JOES ICE HOUSE & TRAILER PARK | 106 |
| EVETTS APARTMENTS | 51 |
| CORDI MARIAN VILLA | 48 |
Frequently asked questions about San Antonio tap water
Is San Antonio tap water safe to drink?
EPA testing detected 40 contaminants in the water serving San Antonio. A detection isn't the same as a violation — most detected levels are within federal limits. Check the level and source for each contaminant above, and your utility's annual Consumer Confidence Report for the official compliance status.
How many water suppliers serve San Antonio?
11 public water suppliers report drinking-water monitoring for San Antonio, Texas to the EPA. Each is listed above with its population served.
What contaminants are in San Antonio's water?
The contaminants EPA monitoring detected in San Antonio include Fluoride, Nitrate, Nitrate-Nitrite, Copper, Chlorite. The full list, with the level at the main supplier and the data source, is in the table above.
Where does this data come from?
Every figure is official EPA drinking-water monitoring — the Lead & Copper Rule, the UCMR-5 nationwide testing program, and the EPA Six-Year Review — not our own testing. Each number is labelled with its source and period.