What was found in ZIP 77066
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 | 259.49999999999994 µg/L 2.6% of the EPA limit 10000 µg/L Main supplier: CITY OF HOUSTON WILLOW CHASE · 14,169 people · 2019
Highest in the ZIP: 1580 µg/L — HARRIS COUNTY MUD 150 · 6,786 people · 2019 | 8/10 | SYR4 |
| Nitrate-Nitrite | 237.5 µg/L 2.4% of the EPA limit 10000 µg/L Main supplier: CITY OF HOUSTON WILLOW CHASE · 14,169 people · 2015
Highest in the ZIP: 1222.5 µg/L — HARRIS COUNTY MUD 150 · 6,786 people · 2015 | 8/10 | SYR4 |
| Fluoride | 140 µg/L 3.5% of the EPA limit 4000 µg/L Main supplier: CITY OF HOUSTON WILLOW CHASE · 14,169 people · 2018
Highest in the ZIP: 398 µg/L — HARRIS COUNTY MUD 180 · 5,892 people · 2017 | 9/10 | SYR4 |
| Barium | 280.65 µg/L 14% of the EPA limit 2000 µg/L Main supplier: CITY OF HOUSTON WILLOW CHASE · 14,169 people · 2019
Highest in the ZIP: 397.3 µg/L — HARRIS COUNTY MUD 33 · 5,181 people · 2019 | 9/10 | SYR4 |
| Nitrite | 301.9999999999999 µg/L 30% of the EPA limit 1000 µg/L Highest in the ZIP: CY CHAMP PUD · 7,428 people · 2015 | 4/10 | SYR4 |
| Copper | 198.79999999999998 µg/L 15% of the EPA limit 1300 µg/L Main supplier: CITY OF HOUSTON WILLOW CHASE · 14,169 people · 2017
Highest in the ZIP: 257.225 µg/L — HARRIS COUNTY MUD 180 · 5,892 people · 2018 | 10/10 | SYR4 |
| Cyanide | 134 µg/L 67% of the EPA limit 200 µg/L Highest in the ZIP: HARRIS COUNTY WCID 109 · 10,134 people · 2017 | 5/10 | SYR4 |
| Xylenes, Total | 3.355 µg/L 0% of the EPA limit 10000 µg/L Main supplier: CITY OF HOUSTON WILLOW CHASE · 14,169 people · 2019
Highest in the ZIP: 97 µg/L — CY CHAMP PUD · 7,428 people · 2019 | 5/10 | SYR4 |
| Total Haloacetic Acids (HAA5) | 23.725 µg/L 40% of the EPA limit 60 µg/L Main supplier: CITY OF HOUSTON WILLOW CHASE · 14,169 people · 2019
Highest in the ZIP: 30.41 µg/L — HARRIS COUNTY WCID 109 · 10,134 people · 2019 | 7/10 | SYR4 |
| Dichloroacetic Acid | 17.244999999999997 µg/L No EPA limit set Main supplier: CITY OF HOUSTON WILLOW CHASE · 14,169 people · 2019
Highest in the ZIP: 23.165 µg/L — HARRIS COUNTY WCID 109 · 10,134 people · 2019 | 7/10 | SYR4 |
| Bromodichloromethane | 4.92 µg/L No EPA limit set Main supplier: CITY OF HOUSTON WILLOW CHASE · 14,169 people · 2019
Highest in the ZIP: 23.009999999999987 µg/L — CY CHAMP PUD · 7,428 people · 2019 | 6/10 | SYR4 |
| TTHM | 11.754999999999995 µg/L 15% of the EPA limit 80 µg/L Main supplier: CITY OF HOUSTON WILLOW CHASE · 14,169 people · 2019
Highest in the ZIP: 22.98999999999999 µg/L — HARRIS COUNTY MUD 150 · 6,786 people · 2019 | 8/10 | SYR4 |
| Lithium | 14 µg/L No EPA limit set Main supplier: CITY OF HOUSTON WILLOW CHASE · 14,169 people · 2025
Highest in the ZIP: 22.2 µg/L — FALLBROOK UTILITY DISTRICT · 6,720 people · 2024 | 6/10 | UCMR-5 |
| Dibromochloromethane | 5.339999999999992 µg/L No EPA limit set Main supplier: CITY OF HOUSTON WILLOW CHASE · 14,169 people · 2019
Highest in the ZIP: 19.4 µg/L — CY CHAMP PUD · 7,428 people · 2019 | 6/10 | SYR4 |
| Chloroform | 3.035 µg/L No EPA limit set Main supplier: CITY OF HOUSTON WILLOW CHASE · 14,169 people · 2019
Highest in the ZIP: 18.815 µg/L — HARRIS COUNTY MUD 150 · 6,786 people · 2019 | 6/10 | SYR4 |
| Lead | 3.4049999999999914 µg/L 23% of the EPA limit 15 µg/L Main supplier: CITY OF HOUSTON WILLOW CHASE · 14,169 people · 2017
Highest in the ZIP: 15.599999999999994 µg/L — HARRIS COUNTY MUD 33 · 5,181 people · 2019 | 10/10 | SYR4 |
| Ethylbenzene | 13.76 µg/L 2% of the EPA limit 700 µg/L Highest in the ZIP: CY CHAMP PUD · 7,428 people · 2019 | 1/10 | SYR4 |
| Arsenic | 3.3749999999999996 µg/L 34% of the EPA limit 10 µg/L Main supplier: CITY OF HOUSTON WILLOW CHASE · 14,169 people · 2019
Highest in the ZIP: 12.774999999999999 µg/L — HARRIS COUNTY MUD 180 · 5,892 people · 2017 | 6/10 | SYR4 |
| Toluene | 11.754999999999999 µg/L 1.2% of the EPA limit 1000 µg/L Highest in the ZIP: CY CHAMP PUD · 7,428 people · 2019 | 2/10 | SYR4 |
| Monochloroacetic Acid | 7.15 µg/L No EPA limit set Highest in the ZIP: CY CHAMP PUD · 7,428 people · 2019 | 6/10 | SYR4 |
| Bromoform | 7.025 µg/L No EPA limit set Main supplier: CITY OF HOUSTON WILLOW CHASE · 14,169 people · 2019 | 3/10 | SYR4 |
| Selenium | 6.865 µg/L 14% of the EPA limit 50 µg/L Main supplier: CITY OF HOUSTON WILLOW CHASE · 14,169 people · 2019 | 1/10 | SYR4 |
| Gross Beta Particle Activity | 4.495 pCi/L No EPA limit set Main supplier: CITY OF HOUSTON WILLOW CHASE · 14,169 people · 2018
Highest in the ZIP: 6.39 pCi/L — HARRIS COUNTY MUD 148 KINGSLAKE · 5,448 people · 2018 | 5/10 | SYR4 |
| Combined Uranium | 5.32 µg/L 18% of the EPA limit 30 µg/L Main supplier: CITY OF HOUSTON WILLOW CHASE · 14,169 people · 2018 | 6/10 | SYR4 |
| Trichloroacetic Acid | 5.199999999999999 µg/L No EPA limit set Main supplier: CITY OF HOUSTON WILLOW CHASE · 14,169 people · 2019 | 7/10 | SYR4 |
| Gross Alpha, Excl. Radon And U | 4 pCi/L 27% of the EPA limit 15 pCi/L Main supplier: CITY OF HOUSTON WILLOW CHASE · 14,169 people · 2018 | 6/10 | SYR4 |
| Dibromoacetic Acid | 3.6500000000000004 µg/L No EPA limit set Main supplier: CITY OF HOUSTON WILLOW CHASE · 14,169 people · 2019 | 1/10 | SYR4 |
| Combined Radium (-226 And -228) | 3.495 pCi/L 70% of the EPA limit 5 pCi/L Highest in the ZIP: HARRIS COUNTY MUD 33 · 5,181 people · 2019 | 5/10 | SYR4 |
| Monobromoacetic Acid | 2 µg/L No EPA limit set Main supplier: CITY OF HOUSTON WILLOW CHASE · 14,169 people · 2019 | 1/10 | SYR4 |
| Di(2-ethylhexyl) Phthalate | 0.7200 µg/L 12% of the EPA limit 6 µg/L Main supplier: CITY OF HOUSTON WILLOW CHASE · 14,169 people · 2019
Highest in the ZIP: 1.8999999999999995 µg/L — HARRIS COUNTY MUD 109 · 9,501 people · 2019 | 4/10 | SYR4 |
| Atrazine | 0.9775 µg/L 33% of the EPA limit 3 µg/L Highest in the ZIP: HARRIS COUNTY MUD 150 · 6,786 people · 2019 | 4/10 | SYR4 |
| Simazine | 0.2770 µg/L 6.9% of the EPA limit 4 µg/L Highest in the ZIP: HARRIS COUNTY MUD 150 · 6,786 people · 2019 | 3/10 | SYR4 |
| 6:2 Fts | 0.1040 µg/L No EPA limit set Highest in the ZIP: FALLBROOK UTILITY DISTRICT · 6,720 people · 2024 | 1/10 | UCMR-5 |
| Pfba | 0.0086 µg/L No EPA limit set Highest in the ZIP: HARRIS COUNTY WCID 109 · 10,134 people · 2025 | 5/10 | UCMR-5 |
| Pfpea | 0.0069 µg/L No EPA limit set Highest in the ZIP: HARRIS COUNTY MUD 150 · 6,786 people · 2025 | 3/10 | UCMR-5 |
| Pfhxa | 0.0055 µg/L No EPA limit set Highest in the ZIP: HARRIS COUNTY MUD 150 · 6,786 people · 2025 | 3/10 | UCMR-5 |
| PFBS | 0.0046 µg/L No EPA limit set Highest in the ZIP: HARRIS COUNTY MUD 148 KINGSLAKE · 5,448 people · 2023 | 1/10 | UCMR-5 |
| Lead | 0.0 mg/L 0% of the EPA limit 0.0150 mg/L Main supplier: CITY OF HOUSTON WILLOW CHASE · 14,169 people · 2023
Highest in the ZIP: 0.0031 mg/L — CY CHAMP PUD · 7,428 people · 2025 | 10/10 | 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.
Water suppliers serving ZIP 77066
| Supplier | State | Population served |
|---|---|---|
| CITY OF HOUSTON WILLOW CHASE | TX | 14,169 |
| HARRIS COUNTY WCID 109 | TX | 10,134 |
| HARRIS COUNTY MUD 109 | TX | 9,501 |
| CY CHAMP PUD | TX | 7,428 |
| HARRIS COUNTY MUD 150 | TX | 6,786 |
| FALLBROOK UTILITY DISTRICT | TX | 6,720 |
| HARRIS COUNTY MUD 180 | TX | 5,892 |
| HARRIS COUNTY MUD 148 KINGSLAKE | TX | 5,448 |
| HARRIS COUNTY MUD 33 | TX | 5,181 |
| FOUNTAINHEAD MUD | TX | 4,614 |
Frequently asked questions about ZIP 77066 tap water
Is the tap water in ZIP 77066 safe to drink?
EPA testing detected 38 contaminants across the water suppliers serving ZIP 77066. 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 77066?
10 public water suppliers report EPA drinking-water monitoring for ZIP 77066. Each is listed above with its population served.
What contaminants are in ZIP 77066's water?
EPA monitoring detected Nitrate, Nitrate-Nitrite, Fluoride, Barium, Nitrite, and others across this ZIP's suppliers. The full list with levels and sources is above.