What was found in ZIP 78664
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 | 5790 µg/L 58% of the EPA limit 10000 µg/L Main supplier: CITY OF ROUND ROCK · 130,662 people · 2019 | 4/4 | SYR4 |
| Nitrate-Nitrite | 5730 µg/L 57% of the EPA limit 10000 µg/L Main supplier: CITY OF ROUND ROCK · 130,662 people · 2015 | 4/4 | SYR4 |
| Fluoride | 315 µg/L 7.9% of the EPA limit 4000 µg/L Main supplier: CITY OF ROUND ROCK · 130,662 people · 2019
Highest in the ZIP: 3500 µg/L — JONAH WATER SUD · 29,861 people · 2017 | 4/4 | SYR4 |
| Copper | 400 µg/L 31% of the EPA limit 1300 µg/L Main supplier: CITY OF ROUND ROCK · 130,662 people · 2018
Highest in the ZIP: 673.5 µg/L — WINDERMERE COMMUNITY · 21,231 people · 2017 | 4/4 | SYR4 |
| Nitrite | 185 µg/L 19% of the EPA limit 1000 µg/L Highest in the ZIP: MANVILLE WSC · 39,648 people · 2015 | 1/4 | SYR4 |
| Xylenes, Total | 142.25 µg/L 1.4% of the EPA limit 10000 µg/L Highest in the ZIP: MANVILLE WSC · 39,648 people · 2019 | 3/4 | SYR4 |
| Barium | 53.5 µg/L 2.7% of the EPA limit 2000 µg/L Main supplier: CITY OF ROUND ROCK · 130,662 people · 2019
Highest in the ZIP: 142 µg/L — MANVILLE WSC · 39,648 people · 2019 | 4/4 | SYR4 |
| Cyanide | 115 µg/L 57% of the EPA limit 200 µg/L Main supplier: CITY OF ROUND ROCK · 130,662 people · 2019
Highest in the ZIP: 117.1 µg/L — MANVILLE WSC · 39,648 people · 2019 | 4/4 | SYR4 |
| TTHM | 64.14 µg/L 80% of the EPA limit 80 µg/L Main supplier: CITY OF ROUND ROCK · 130,662 people · 2019
Highest in the ZIP: 92.1 µg/L — JONAH WATER SUD · 29,861 people · 2019 | 4/4 | SYR4 |
| Lithium | 13.5 µg/L No EPA limit set Main supplier: CITY OF ROUND ROCK · 130,662 people · 2025
Highest in the ZIP: 83.8 µg/L — MANVILLE WSC · 39,648 people · 2023 | 4/4 | UCMR-5 |
| Total Haloacetic Acids (HAA5) | 25.64 µg/L 43% of the EPA limit 60 µg/L Main supplier: CITY OF ROUND ROCK · 130,662 people · 2019
Highest in the ZIP: 41.6 µg/L — JONAH WATER SUD · 29,861 people · 2019 | 4/4 | SYR4 |
| Chloroform | 19.89 µg/L No EPA limit set Main supplier: CITY OF ROUND ROCK · 130,662 people · 2019
Highest in the ZIP: 40.56 µg/L — JONAH WATER SUD · 29,861 people · 2019 | 4/4 | SYR4 |
| Bromodichloromethane | 24.01 µg/L No EPA limit set Main supplier: CITY OF ROUND ROCK · 130,662 people · 2019
Highest in the ZIP: 31.74 µg/L — JONAH WATER SUD · 29,861 people · 2019 | 4/4 | SYR4 |
| Ethylbenzene | 28.25 µg/L 4% of the EPA limit 700 µg/L Highest in the ZIP: MANVILLE WSC · 39,648 people · 2019 | 2/4 | SYR4 |
| Dibromochloromethane | 23.4 µg/L No EPA limit set Main supplier: CITY OF ROUND ROCK · 130,662 people · 2019
Highest in the ZIP: 28.19 µg/L — JONAH WATER SUD · 29,861 people · 2019 | 4/4 | SYR4 |
| Di(2-ethylhexyl) Phthalate | 22.704 µg/L 378% of the EPA limit, at the 95th percentile of samples — 6 µg/L Highest in the ZIP: WINDERMERE COMMUNITY · 21,231 people · 2019 | 1/4 | SYR4 |
| Trichloroacetic Acid | 8.345 µg/L No EPA limit set Main supplier: CITY OF ROUND ROCK · 130,662 people · 2019
Highest in the ZIP: 21.5 µg/L — JONAH WATER SUD · 29,861 people · 2019 | 4/4 | SYR4 |
| Lead | 7.91 µg/L 53% of the EPA limit 15 µg/L Main supplier: CITY OF ROUND ROCK · 130,662 people · 2018
Highest in the ZIP: 20.67 µg/L — WINDERMERE COMMUNITY · 21,231 people · 2017 | 4/4 | SYR4 |
| Dichloroacetic Acid | 13 µg/L No EPA limit set Main supplier: CITY OF ROUND ROCK · 130,662 people · 2019
Highest in the ZIP: 19.02 µg/L — JONAH WATER SUD · 29,861 people · 2019 | 4/4 | SYR4 |
| Bromoform | 17.545 µg/L No EPA limit set Main supplier: CITY OF ROUND ROCK · 130,662 people · 2019 | 4/4 | SYR4 |
| Gross Alpha, Excl. Radon And U | 13.51 pCi/L 90% of the EPA limit 15 pCi/L Highest in the ZIP: JONAH WATER SUD · 29,861 people · 2017 | 3/4 | SYR4 |
| Dibromoacetic Acid | 9.42 µg/L No EPA limit set Main supplier: CITY OF ROUND ROCK · 130,662 people · 2019 | 4/4 | SYR4 |
| Gross Beta Particle Activity | 7.44 pCi/L No EPA limit set Highest in the ZIP: JONAH WATER SUD · 29,861 people · 2017 | 3/4 | SYR4 |
| Selenium | 4.38 µg/L 8.8% of the EPA limit 50 µg/L Main supplier: CITY OF ROUND ROCK · 130,662 people · 2019
Highest in the ZIP: 6.525 µg/L — MANVILLE WSC · 39,648 people · 2019 | 2/4 | SYR4 |
| Monochloroacetic Acid | 5.32 µg/L No EPA limit set Main supplier: CITY OF ROUND ROCK · 130,662 people · 2019
Highest in the ZIP: 6.12 µg/L — JONAH WATER SUD · 29,861 people · 2019 | 4/4 | SYR4 |
| Chromium | 4.0695 µg/L 4.1% of the EPA limit 100 µg/L Highest in the ZIP: MANVILLE WSC · 39,648 people · 2019 | 2/4 | SYR4 |
| Arsenic | 1.68 µg/L 17% of the EPA limit 10 µg/L Main supplier: CITY OF ROUND ROCK · 130,662 people · 2019
Highest in the ZIP: 3.3775 µg/L — WINDERMERE COMMUNITY · 21,231 people · 2019 | 4/4 | SYR4 |
| Combined Radium (-226 And -228) | 3.364 pCi/L 67% of the EPA limit 5 pCi/L Highest in the ZIP: JONAH WATER SUD · 29,861 people · 2017 | 3/4 | SYR4 |
| Vinyl Chloride | 3.2 µg/L 160% of the EPA limit, at the 95th percentile of samples — 2 µg/L Highest in the ZIP: JONAH WATER SUD · 29,861 people · 2019 | 1/4 | SYR4 |
| Combined Uranium | 2.3 µg/L 7.7% of the EPA limit 30 µg/L Highest in the ZIP: MANVILLE WSC · 39,648 people · 2019 | 3/4 | SYR4 |
| Monobromoacetic Acid | 2 µg/L No EPA limit set Main supplier: CITY OF ROUND ROCK · 130,662 people · 2019
Highest in the ZIP: 2.15 µg/L — JONAH WATER SUD · 29,861 people · 2019 | 4/4 | SYR4 |
| Diquat | 1.64 µg/L 8.2% of the EPA limit 20 µg/L Highest in the ZIP: WINDERMERE COMMUNITY · 21,231 people · 2019 | 1/4 | SYR4 |
| Thallium, Total | 1.039 µg/L 52% of the EPA limit 2 µg/L Highest in the ZIP: WINDERMERE COMMUNITY · 21,231 people · 2019 | 1/4 | SYR4 |
| Dalapon | 1 µg/L 0.5% of the EPA limit 200 µg/L Highest in the ZIP: JONAH WATER SUD · 29,861 people · 2019 | 1/4 | SYR4 |
| Atrazine | 0.1795 µg/L 6% of the EPA limit 3 µg/L Main supplier: CITY OF ROUND ROCK · 130,662 people · 2019
Highest in the ZIP: 0.6525 µg/L — MANVILLE WSC · 39,648 people · 2019 | 2/4 | SYR4 |
| Simazine | 0.1480 µg/L 3.7% of the EPA limit 4 µg/L Highest in the ZIP: MANVILLE WSC · 39,648 people · 2019 | 1/4 | SYR4 |
| PFNA | 0.0243 µg/L No EPA limit set Highest in the ZIP: MANVILLE WSC · 39,648 people · 2023 | 1/4 | UCMR-5 |
| Pfpea | 0.0067 µg/L No EPA limit set Main supplier: CITY OF ROUND ROCK · 130,662 people · 2025
Highest in the ZIP: 0.0212 µg/L — JONAH WATER SUD · 29,861 people · 2024 | 4/4 | UCMR-5 |
| Pfba | 0.0051 µg/L No EPA limit set Main supplier: CITY OF ROUND ROCK · 130,662 people · 2025
Highest in the ZIP: 0.0158 µg/L — JONAH WATER SUD · 29,861 people · 2024 | 4/4 | UCMR-5 |
| PFOS | 0.0124 µg/L No EPA limit set Highest in the ZIP: MANVILLE WSC · 39,648 people · 2023 | 3/4 | UCMR-5 |
| PFBS | 0.0067 µg/L No EPA limit set Main supplier: CITY OF ROUND ROCK · 130,662 people · 2025
Highest in the ZIP: 0.0100 µg/L — MANVILLE WSC · 39,648 people · 2023 | 4/4 | UCMR-5 |
| Pfhxa | 0.0037 µg/L No EPA limit set Main supplier: CITY OF ROUND ROCK · 130,662 people · 2025
Highest in the ZIP: 0.0092 µg/L — JONAH WATER SUD · 29,861 people · 2024 | 4/4 | UCMR-5 |
| PFHXS | 0.0070 µg/L No EPA limit set Highest in the ZIP: MANVILLE WSC · 39,648 people · 2023 | 3/4 | UCMR-5 |
| PFOA | 0.0059 µg/L No EPA limit set Highest in the ZIP: MANVILLE WSC · 39,648 people · 2023 | 2/4 | UCMR-5 |
| Lead | 0.0050 mg/L 34% of the EPA limit 0.0150 mg/L Main supplier: CITY OF ROUND ROCK · 130,662 people · 2023 | 4/4 | LCR |
| Pfhpa | 0.0043 µg/L No EPA limit set Highest in the ZIP: MANVILLE WSC · 39,648 people · 2023 | 1/4 | UCMR-5 |
| Pfuna | 0.0027 µg/L No EPA limit set Highest in the ZIP: MANVILLE WSC · 39,648 people · 2023 | 1/4 | 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 78664
| Supplier | State | Population served |
|---|---|---|
| CITY OF ROUND ROCK | TX | 130,662 |
| MANVILLE WSC | TX | 39,648 |
| JONAH WATER SUD | TX | 29,861 |
| WINDERMERE COMMUNITY | TX | 21,231 |
Frequently asked questions about ZIP 78664 tap water
Is the tap water in ZIP 78664 safe to drink?
EPA testing detected 47 contaminants across the water suppliers serving ZIP 78664. 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 78664?
4 public water suppliers report EPA drinking-water monitoring for ZIP 78664. Each is listed above with its population served.
What contaminants are in ZIP 78664's water?
EPA monitoring detected Nitrate, Nitrate-Nitrite, Fluoride, Copper, Nitrite, and others across this ZIP's suppliers. The full list with levels and sources is above.