What was found in ZIP 91764
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-Nitrite | 710000 µg/L 7100% of the EPA limit, at the 95th percentile of samples — 10000 µg/L Main supplier: CUCAMONGA VALLEY WATER DISTRICT · 211,069 people · 2019 | 2/2 | SYR4 |
| Nitrate | 15000 µg/L 150% of the EPA limit, at the 95th percentile of samples — 10000 µg/L Main supplier: CUCAMONGA VALLEY WATER DISTRICT · 211,069 people · 2019 | 2/2 | SYR4 |
| Nitrite | 4525 µg/L 453% of the EPA limit, at the 95th percentile of samples — 1000 µg/L Highest in the ZIP: ONTARIO MUNICIPAL UTILITIES COMPANY · 185,010 people · 2019 | 1/2 | SYR4 |
| Fluoride | 587 µg/L 15% of the EPA limit 4000 µg/L Main supplier: CUCAMONGA VALLEY WATER DISTRICT · 211,069 people · 2019 | 2/2 | SYR4 |
| Barium | 116.5 µg/L 5.8% of the EPA limit 2000 µg/L Main supplier: CUCAMONGA VALLEY WATER DISTRICT · 211,069 people · 2019
Highest in the ZIP: 139.5 µg/L — ONTARIO MUNICIPAL UTILITIES COMPANY · 185,010 people · 2019 | 2/2 | SYR4 |
| TTHM | 97.3 µg/L 122% of the EPA limit, at the 95th percentile of samples — 80 µg/L Main supplier: CUCAMONGA VALLEY WATER DISTRICT · 211,069 people · 2019 | 2/2 | SYR4 |
| Copper | 70 µg/L 5.4% of the EPA limit 1300 µg/L Main supplier: CUCAMONGA VALLEY WATER DISTRICT · 211,069 people · 2019 | 1/2 | SYR4 |
| Dibromochloromethane | 41.15 µg/L No EPA limit set Main supplier: CUCAMONGA VALLEY WATER DISTRICT · 211,069 people · 2019 | 2/2 | SYR4 |
| Bromoform | 37.93 µg/L No EPA limit set Main supplier: CUCAMONGA VALLEY WATER DISTRICT · 211,069 people · 2019 | 2/2 | SYR4 |
| Total Haloacetic Acids (HAA5) | 18.91 µg/L 32% of the EPA limit 60 µg/L Main supplier: CUCAMONGA VALLEY WATER DISTRICT · 211,069 people · 2019
Highest in the ZIP: 31.5 µg/L — ONTARIO MUNICIPAL UTILITIES COMPANY · 185,010 people · 2019 | 2/2 | SYR4 |
| Monochloroacetic Acid | 27 µg/L No EPA limit set Highest in the ZIP: ONTARIO MUNICIPAL UTILITIES COMPANY · 185,010 people · 2019 | 1/2 | SYR4 |
| Bromodichloromethane | 25 µg/L No EPA limit set Main supplier: CUCAMONGA VALLEY WATER DISTRICT · 211,069 people · 2019 | 2/2 | SYR4 |
| Chloroform | 22.05 µg/L No EPA limit set Main supplier: CUCAMONGA VALLEY WATER DISTRICT · 211,069 people · 2019 | 2/2 | SYR4 |
| Combined Uranium | 13.4398 µg/L 45% of the EPA limit 30 µg/L Main supplier: CUCAMONGA VALLEY WATER DISTRICT · 211,069 people · 2017 | 1/2 | SYR4 |
| Dibromoacetic Acid | 11 µg/L No EPA limit set Main supplier: CUCAMONGA VALLEY WATER DISTRICT · 211,069 people · 2019 | 2/2 | SYR4 |
| Trichloroacetic Acid | 8 µg/L No EPA limit set Main supplier: CUCAMONGA VALLEY WATER DISTRICT · 211,069 people · 2019 | 2/2 | SYR4 |
| Chromium | 7.45 µg/L 7.5% of the EPA limit 100 µg/L Highest in the ZIP: ONTARIO MUNICIPAL UTILITIES COMPANY · 185,010 people · 2019 | 1/2 | SYR4 |
| Monobromoacetic Acid | 1.8 µg/L No EPA limit set Main supplier: CUCAMONGA VALLEY WATER DISTRICT · 211,069 people · 2019
Highest in the ZIP: 7.16 µg/L — ONTARIO MUNICIPAL UTILITIES COMPANY · 185,010 people · 2019 | 2/2 | SYR4 |
| Dichloroacetic Acid | 6.68 µg/L No EPA limit set Main supplier: CUCAMONGA VALLEY WATER DISTRICT · 211,069 people · 2019 | 2/2 | SYR4 |
| Arsenic | 5.325 µg/L 53% of the EPA limit 10 µg/L Main supplier: CUCAMONGA VALLEY WATER DISTRICT · 211,069 people · 2019 | 2/2 | SYR4 |
| Picloram | 1.4 µg/L 0.3% of the EPA limit 500 µg/L Main supplier: CUCAMONGA VALLEY WATER DISTRICT · 211,069 people · 2019 | 1/2 | SYR4 |
| Dichloromethane | 0.9800 µg/L 20% of the EPA limit 5 µg/L Main supplier: CUCAMONGA VALLEY WATER DISTRICT · 211,069 people · 2019 | 1/2 | SYR4 |
| 1,2-DIBROMO-3-CHLOROPROPANE | 0.2900 µg/L 145% of the EPA limit, at the 95th percentile of samples — 0.2000 µg/L Main supplier: CUCAMONGA VALLEY WATER DISTRICT · 211,069 people · 2019 | 2/2 | SYR4 |
| PFOA | 0.0300 µg/L No EPA limit set Highest in the ZIP: ONTARIO MUNICIPAL UTILITIES COMPANY · 185,010 people · 2024 | 1/2 | UCMR-5 |
| Ethylene Dibromide | 0.0210 µg/L 42% of the EPA limit 0.0500 µg/L Highest in the ZIP: ONTARIO MUNICIPAL UTILITIES COMPANY · 185,010 people · 2019 | 1/2 | SYR4 |
| Pfhxa | 0.0071 µg/L No EPA limit set Highest in the ZIP: ONTARIO MUNICIPAL UTILITIES COMPANY · 185,010 people · 2024 | 1/2 | UCMR-5 |
| Pfpea | 0.0067 µg/L No EPA limit set Highest in the ZIP: ONTARIO MUNICIPAL UTILITIES COMPANY · 185,010 people · 2024 | 1/2 | UCMR-5 |
| Pfba | 0.0064 µg/L No EPA limit set Highest in the ZIP: ONTARIO MUNICIPAL UTILITIES COMPANY · 185,010 people · 2024 | 1/2 | UCMR-5 |
| PFOS | 0.0052 µg/L No EPA limit set Highest in the ZIP: ONTARIO MUNICIPAL UTILITIES COMPANY · 185,010 people · 2024 | 1/2 | UCMR-5 |
| PFHXS | 0.0042 µg/L No EPA limit set Highest in the ZIP: ONTARIO MUNICIPAL UTILITIES COMPANY · 185,010 people · 2024 | 1/2 | UCMR-5 |
| Lead | 0.0 mg/L 0% of the EPA limit 0.0150 mg/L Main supplier: CUCAMONGA VALLEY WATER DISTRICT · 211,069 people · 2024
Highest in the ZIP: 0.00060 mg/L — ONTARIO MUNICIPAL UTILITIES COMPANY · 185,010 people · 2024 | 2/2 | 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 91764
| Supplier | State | Population served |
|---|---|---|
| CUCAMONGA VALLEY WATER DISTRICT | CA | 211,069 |
| ONTARIO MUNICIPAL UTILITIES COMPANY | CA | 185,010 |
Frequently asked questions about ZIP 91764 tap water
Is the tap water in ZIP 91764 safe to drink?
EPA testing detected 31 contaminants across the water suppliers serving ZIP 91764. 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 91764?
2 public water suppliers report EPA drinking-water monitoring for ZIP 91764. Each is listed above with its population served.
What contaminants are in ZIP 91764's water?
EPA monitoring detected Nitrate-Nitrite, Nitrate, Nitrite, Fluoride, Barium, and others across this ZIP's suppliers. The full list with levels and sources is above.