What was found in ZIP 78728
The level at this ZIP's main supplier, the highest level anywhere in it, the EPA limit for each, and where the figure comes from.
| Contaminant | Level vs EPA limit | Suppliers | Source |
|---|---|---|---|
| Nitrate | 560 µg/L 5.6% of the EPA limit 10000 µg/L Main supplier: CITY OF AUSTIN WATER & WASTEWATER · 1,115,323 people · 2019
Highest in the ZIP: 5790 µg/L — CITY OF ROUND ROCK · 130,662 people · 2019 | 2/3 | SYR4 |
| Nitrate-Nitrite | 5730 µg/L 57% of the EPA limit 10000 µg/L Highest in the ZIP: CITY OF ROUND ROCK · 130,662 people · 2015 | 1/3 | SYR4 |
| Fluoride | 820 µg/L 21% of the EPA limit 4000 µg/L Main supplier: CITY OF AUSTIN WATER & WASTEWATER · 1,115,323 people · 2019 | 2/3 | SYR4 |
| Copper | 9.599999999999994 µg/L 0.7% of the EPA limit 1300 µg/L Main supplier: CITY OF AUSTIN WATER & WASTEWATER · 1,115,323 people · 2018
Highest in the ZIP: 400 µg/L — CITY OF ROUND ROCK · 130,662 people · 2018 | 3/3 | SYR4 |
| Cyanide | 132.5 µg/L 66% of the EPA limit 200 µg/L Main supplier: CITY OF AUSTIN WATER & WASTEWATER · 1,115,323 people · 2019 | 2/3 | SYR4 |
| TTHM | 59.04499999999999 µg/L 74% of the EPA limit 80 µg/L Main supplier: CITY OF AUSTIN WATER & WASTEWATER · 1,115,323 people · 2019
Highest in the ZIP: 64.13999999999999 µg/L — CITY OF ROUND ROCK · 130,662 people · 2019 | 3/3 | SYR4 |
| Barium | 11.91 µg/L 0.6% of the EPA limit 2000 µg/L Main supplier: CITY OF AUSTIN WATER & WASTEWATER · 1,115,323 people · 2019
Highest in the ZIP: 53.5 µg/L — CITY OF ROUND ROCK · 130,662 people · 2019 | 2/3 | SYR4 |
| Chloroform | 30.285 µg/L No EPA limit set Main supplier: CITY OF AUSTIN WATER & WASTEWATER · 1,115,323 people · 2019 | 3/3 | SYR4 |
| Total Haloacetic Acids (HAA5) | 23.909999999999997 µg/L 40% of the EPA limit 60 µg/L Main supplier: CITY OF AUSTIN WATER & WASTEWATER · 1,115,323 people · 2019
Highest in the ZIP: 25.639999999999986 µg/L — CITY OF ROUND ROCK · 130,662 people · 2019 | 3/3 | SYR4 |
| Bromodichloromethane | 18.884999999999998 µg/L No EPA limit set Main supplier: CITY OF AUSTIN WATER & WASTEWATER · 1,115,323 people · 2019
Highest in the ZIP: 24.009999999999998 µg/L — CITY OF ROUND ROCK · 130,662 people · 2019 | 3/3 | SYR4 |
| Dibromochloromethane | 12.985 µg/L No EPA limit set Main supplier: CITY OF AUSTIN WATER & WASTEWATER · 1,115,323 people · 2019
Highest in the ZIP: 23.4 µg/L — CITY OF ROUND ROCK · 130,662 people · 2019 | 3/3 | SYR4 |
| Bromoform | 3.3549999999999995 µg/L No EPA limit set Main supplier: CITY OF AUSTIN WATER & WASTEWATER · 1,115,323 people · 2019
Highest in the ZIP: 17.544999999999995 µg/L — CITY OF ROUND ROCK · 130,662 people · 2019 | 3/3 | SYR4 |
| Dichloroacetic Acid | 15.409999999999997 µg/L No EPA limit set Main supplier: CITY OF AUSTIN WATER & WASTEWATER · 1,115,323 people · 2019 | 3/3 | SYR4 |
| Lithium | 13.5 µg/L No EPA limit set Highest in the ZIP: CITY OF ROUND ROCK · 130,662 people · 2025 | 1/3 | UCMR-5 |
| Dibromoacetic Acid | 4.1 µg/L No EPA limit set Main supplier: CITY OF AUSTIN WATER & WASTEWATER · 1,115,323 people · 2019
Highest in the ZIP: 9.42 µg/L — CITY OF ROUND ROCK · 130,662 people · 2019 | 3/3 | SYR4 |
| Trichloroacetic Acid | 7.069999999999996 µg/L No EPA limit set Main supplier: CITY OF AUSTIN WATER & WASTEWATER · 1,115,323 people · 2019
Highest in the ZIP: 8.344999999999999 µg/L — CITY OF ROUND ROCK · 130,662 people · 2019 | 3/3 | SYR4 |
| Lead | 3.923 µg/L 26% of the EPA limit 15 µg/L Main supplier: CITY OF AUSTIN WATER & WASTEWATER · 1,115,323 people · 2018
Highest in the ZIP: 7.909999999999989 µg/L — CITY OF ROUND ROCK · 130,662 people · 2018 | 3/3 | SYR4 |
| Monochloroacetic Acid | 3.525 µg/L No EPA limit set Main supplier: CITY OF AUSTIN WATER & WASTEWATER · 1,115,323 people · 2019
Highest in the ZIP: 5.319999999999999 µg/L — CITY OF ROUND ROCK · 130,662 people · 2019 | 3/3 | SYR4 |
| Gross Beta Particle Activity | 4.8 pCi/L No EPA limit set Main supplier: CITY OF AUSTIN WATER & WASTEWATER · 1,115,323 people · 2018 | 1/3 | SYR4 |
| Selenium | 4.38 µg/L 8.8% of the EPA limit 50 µg/L Highest in the ZIP: CITY OF ROUND ROCK · 130,662 people · 2019 | 1/3 | SYR4 |
| Diquat | 4.03 µg/L 20% of the EPA limit 20 µg/L Main supplier: CITY OF AUSTIN WATER & WASTEWATER · 1,115,323 people · 2019 | 1/3 | SYR4 |
| Monobromoacetic Acid | 1.43 µg/L No EPA limit set Main supplier: CITY OF AUSTIN WATER & WASTEWATER · 1,115,323 people · 2019
Highest in the ZIP: 2 µg/L — CITY OF ROUND ROCK · 130,662 people · 2019 | 3/3 | SYR4 |
| Arsenic | 0.9340 µg/L 9.3% of the EPA limit 10 µg/L Main supplier: CITY OF AUSTIN WATER & WASTEWATER · 1,115,323 people · 2019
Highest in the ZIP: 1.68 µg/L — CITY OF ROUND ROCK · 130,662 people · 2019 | 2/3 | SYR4 |
| Chromium | 0.4283 µg/L 0.4% of the EPA limit 100 µg/L Main supplier: CITY OF AUSTIN WATER & WASTEWATER · 1,115,323 people · 2019 | 1/3 | SYR4 |
| Atrazine | 0.1795 µg/L 6% of the EPA limit 3 µg/L Highest in the ZIP: CITY OF ROUND ROCK · 130,662 people · 2019 | 1/3 | SYR4 |
| Simazine | 0.0800 µg/L 2% of the EPA limit 4 µg/L Main supplier: CITY OF AUSTIN WATER & WASTEWATER · 1,115,323 people · 2019 | 1/3 | SYR4 |
| Pfba | 0.0084 µg/L No EPA limit set Main supplier: CITY OF AUSTIN WATER & WASTEWATER · 1,115,323 people · 2024 | 3/3 | UCMR-5 |
| PFBS | 0.0051 µg/L No EPA limit set Main supplier: CITY OF AUSTIN WATER & WASTEWATER · 1,115,323 people · 2024
Highest in the ZIP: 0.0067 µg/L — CITY OF ROUND ROCK · 130,662 people · 2025 | 2/3 | UCMR-5 |
| Pfpea | 0.0041 µg/L No EPA limit set Main supplier: CITY OF AUSTIN WATER & WASTEWATER · 1,115,323 people · 2024
Highest in the ZIP: 0.0067 µg/L — CITY OF ROUND ROCK · 130,662 people · 2025 | 2/3 | UCMR-5 |
| PFHXS | 0.0062 µg/L No EPA limit set Main supplier: CITY OF AUSTIN WATER & WASTEWATER · 1,115,323 people · 2024 | 1/3 | UCMR-5 |
| Lead | 0.0 mg/L 0% of the EPA limit 0.0150 mg/L Main supplier: CITY OF AUSTIN WATER & WASTEWATER · 1,115,323 people · 2024
Highest in the ZIP: 0.0050 mg/L — CITY OF ROUND ROCK · 130,662 people · 2023 | 3/3 | LCR |
| PFOS | 0.0048 µg/L No EPA limit set Main supplier: CITY OF AUSTIN WATER & WASTEWATER · 1,115,323 people · 2024 | 1/3 | UCMR-5 |
| Pfhxa | 0.0033 µg/L No EPA limit set Main supplier: CITY OF AUSTIN WATER & WASTEWATER · 1,115,323 people · 2024
Highest in the ZIP: 0.0037 µg/L — CITY OF ROUND ROCK · 130,662 people · 2025 | 2/3 | UCMR-5 |
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.
Water suppliers serving ZIP 78728
| Supplier | State | Population served |
|---|---|---|
| CITY OF AUSTIN WATER & WASTEWATER | TX | 1,115,323 |
| CITY OF ROUND ROCK | TX | 130,662 |
| WELLS BRANCH MUD 1 | TX | 18,015 |
Frequently asked questions about ZIP 78728 tap water
Is the tap water in ZIP 78728 safe to drink?
EPA testing detected 33 contaminants across the water suppliers serving ZIP 78728. A detection isn't the same as a violation — most levels are within federal limits. See each level and source above, and your utility's annual Consumer Confidence Report for the official status.
Which water suppliers serve ZIP 78728?
3 public water suppliers report EPA drinking-water monitoring for ZIP 78728. Each is listed above with its population served.
What contaminants are in ZIP 78728's water?
EPA monitoring detected Nitrate, Nitrate-Nitrite, Fluoride, Copper, Cyanide, and others across this ZIP's suppliers. The full list with levels and sources is above.