What was found in ZIP 91709
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 | 17000 µg/L 170% of the EPA limit, at the 95th percentile of samples — 10000 µg/L Main supplier: POMONA - CITY, WATER DEPT. · 151,713 people · 2019 | 2/2 | SYR4 |
| Nitrate | 16272 µg/L 163% of the EPA limit, at the 95th percentile of samples — 10000 µg/L Main supplier: POMONA - CITY, WATER DEPT. · 151,713 people · 2019 | 2/2 | SYR4 |
| Fluoride | 504 µg/L 13% of the EPA limit 4000 µg/L Main supplier: POMONA - CITY, WATER DEPT. · 151,713 people · 2019
Highest in the ZIP: 605 µg/L — CHINO HILLS, CITY OF · 76,414 people · 2019 | 2/2 | SYR4 |
| Barium | 100 µg/L 5% of the EPA limit 2000 µg/L Main supplier: POMONA - CITY, WATER DEPT. · 151,713 people · 2019 | 2/2 | SYR4 |
| Chromium | 88 µg/L 88% of the EPA limit 100 µg/L Main supplier: POMONA - CITY, WATER DEPT. · 151,713 people · 2019 | 2/2 | SYR4 |
| Copper | 79 µg/L 6.1% of the EPA limit 1300 µg/L Highest in the ZIP: CHINO HILLS, CITY OF · 76,414 people · 2019 | 1/2 | SYR4 |
| TTHM | 39 µg/L 49% of the EPA limit 80 µg/L Main supplier: POMONA - CITY, WATER DEPT. · 151,713 people · 2019
Highest in the ZIP: 66 µg/L — CHINO HILLS, CITY OF · 76,414 people · 2019 | 2/2 | SYR4 |
| 1,1-Dichloroethylene | 28 µg/L 400% of the EPA limit, at the 95th percentile of samples — 7 µg/L Main supplier: POMONA - CITY, WATER DEPT. · 151,713 people · 2019 | 2/2 | SYR4 |
| Dibromochloromethane | 13 µg/L No EPA limit set Main supplier: POMONA - CITY, WATER DEPT. · 151,713 people · 2019
Highest in the ZIP: 25.2 µg/L — CHINO HILLS, CITY OF · 76,414 people · 2019 | 2/2 | SYR4 |
| Arsenic | 8.365 µg/L 84% of the EPA limit 10 µg/L Main supplier: POMONA - CITY, WATER DEPT. · 151,713 people · 2019
Highest in the ZIP: 22.75 µg/L — CHINO HILLS, CITY OF · 76,414 people · 2019 | 2/2 | SYR4 |
| Bromodichloromethane | 12 µg/L No EPA limit set Main supplier: POMONA - CITY, WATER DEPT. · 151,713 people · 2019
Highest in the ZIP: 20 µg/L — CHINO HILLS, CITY OF · 76,414 people · 2019 | 2/2 | SYR4 |
| Bromoform | 9.425 µg/L No EPA limit set Main supplier: POMONA - CITY, WATER DEPT. · 151,713 people · 2019
Highest in the ZIP: 19 µg/L — CHINO HILLS, CITY OF · 76,414 people · 2019 | 2/2 | SYR4 |
| Total Haloacetic Acids (HAA5) | 16.05 µg/L 27% of the EPA limit 60 µg/L Main supplier: POMONA - CITY, WATER DEPT. · 151,713 people · 2019
Highest in the ZIP: 16.65 µg/L — CHINO HILLS, CITY OF · 76,414 people · 2019 | 2/2 | SYR4 |
| Chloroform | 13 µg/L No EPA limit set Main supplier: POMONA - CITY, WATER DEPT. · 151,713 people · 2019
Highest in the ZIP: 14 µg/L — CHINO HILLS, CITY OF · 76,414 people · 2019 | 2/2 | SYR4 |
| Selenium | 7.02 µg/L 14% of the EPA limit 50 µg/L Main supplier: POMONA - CITY, WATER DEPT. · 151,713 people · 2019
Highest in the ZIP: 10.54 µg/L — CHINO HILLS, CITY OF · 76,414 people · 2019 | 2/2 | SYR4 |
| Trichloroethylene | 10 µg/L 200% of the EPA limit, at the 95th percentile of samples — 5 µg/L Main supplier: POMONA - CITY, WATER DEPT. · 151,713 people · 2019 | 2/2 | SYR4 |
| Monochloroacetic Acid | 9.48 µg/L No EPA limit set Highest in the ZIP: CHINO HILLS, CITY OF · 76,414 people · 2019 | 1/2 | SYR4 |
| Dichloroacetic Acid | 8.365 µg/L No EPA limit set Main supplier: POMONA - CITY, WATER DEPT. · 151,713 people · 2019
Highest in the ZIP: 9.445 µg/L — CHINO HILLS, CITY OF · 76,414 people · 2019 | 2/2 | SYR4 |
| Lithium | 9.3 µg/L No EPA limit set Main supplier: POMONA - CITY, WATER DEPT. · 151,713 people · 2024 | 1/2 | UCMR-5 |
| Tetrachloroethylene | 7.6 µg/L 152% of the EPA limit, at the 95th percentile of samples — 5 µg/L Main supplier: POMONA - CITY, WATER DEPT. · 151,713 people · 2019 | 2/2 | SYR4 |
| Combined Uranium | 6.8724 µg/L 23% of the EPA limit 30 µg/L Main supplier: POMONA - CITY, WATER DEPT. · 151,713 people · 2019 | 1/2 | SYR4 |
| Trichloroacetic Acid | 6.8 µg/L No EPA limit set Main supplier: POMONA - CITY, WATER DEPT. · 151,713 people · 2019 | 2/2 | SYR4 |
| Lead | 6.5 µg/L 43% of the EPA limit 15 µg/L Highest in the ZIP: CHINO HILLS, CITY OF · 76,414 people · 2019 | 1/2 | SYR4 |
| Dibromoacetic Acid | 3.47 µg/L No EPA limit set Main supplier: POMONA - CITY, WATER DEPT. · 151,713 people · 2019
Highest in the ZIP: 6.46 µg/L — CHINO HILLS, CITY OF · 76,414 people · 2019 | 2/2 | SYR4 |
| Monobromoacetic Acid | 2.175 µg/L No EPA limit set Main supplier: POMONA - CITY, WATER DEPT. · 151,713 people · 2019
Highest in the ZIP: 3.105 µg/L — CHINO HILLS, CITY OF · 76,414 people · 2019 | 2/2 | SYR4 |
| Thallium, Total | 1.2 µg/L 60% of the EPA limit 2 µg/L Main supplier: POMONA - CITY, WATER DEPT. · 151,713 people · 2019 | 1/2 | SYR4 |
| 1,2-DIBROMO-3-CHLOROPROPANE | 0.0882 µg/L 44% of the EPA limit 0.2000 µg/L Main supplier: POMONA - CITY, WATER DEPT. · 151,713 people · 2019 | 1/2 | SYR4 |
| PFOS | 0.0180 µg/L No EPA limit set Main supplier: POMONA - CITY, WATER DEPT. · 151,713 people · 2024 | 1/2 | UCMR-5 |
| PFHXS | 0.0079 µg/L No EPA limit set Main supplier: POMONA - CITY, WATER DEPT. · 151,713 people · 2024 | 1/2 | UCMR-5 |
| PFOA | 0.0071 µg/L No EPA limit set Main supplier: POMONA - CITY, WATER DEPT. · 151,713 people · 2024 | 1/2 | UCMR-5 |
| Pfpea | 0.0044 µg/L No EPA limit set Main supplier: POMONA - CITY, WATER DEPT. · 151,713 people · 2024 | 1/2 | UCMR-5 |
| Pfhxa | 0.0041 µg/L No EPA limit set Main supplier: POMONA - CITY, WATER DEPT. · 151,713 people · 2024 | 1/2 | UCMR-5 |
| PFBS | 0.0032 µg/L No EPA limit set Main supplier: POMONA - CITY, WATER DEPT. · 151,713 people · 2024 | 1/2 | UCMR-5 |
| Lead | 0.0021 mg/L 14% of the EPA limit 0.0150 mg/L Main supplier: POMONA - CITY, WATER DEPT. · 151,713 people · 2025 | 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 91709
| Supplier | State | Population served |
|---|---|---|
| POMONA - CITY, WATER DEPT. | CA | 151,713 |
| CHINO HILLS, CITY OF | CA | 76,414 |
Frequently asked questions about ZIP 91709 tap water
Is the tap water in ZIP 91709 safe to drink?
EPA testing detected 34 contaminants across the water suppliers serving ZIP 91709. 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 91709?
2 public water suppliers report EPA drinking-water monitoring for ZIP 91709. Each is listed above with its population served.
What contaminants are in ZIP 91709's water?
EPA monitoring detected Nitrate-Nitrite, Nitrate, Fluoride, Barium, Chromium, and others across this ZIP's suppliers. The full list with levels and sources is above.