What was found in ZIP 91750
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 | 21000 µg/L 210% of the EPA limit, at the 95th percentile of samples — 10000 µg/L Highest in the ZIP: LA VERNE, CITY WD · 31,334 people · 2019 | 1/3 | SYR4 |
| Fluoride | 800 µg/L 20% of the EPA limit 4000 µg/L Highest in the ZIP: LA VERNE, CITY WD · 31,334 people · 2019 | 1/3 | SYR4 |
| Barium | 96.4 µg/L 4.8% of the EPA limit 2000 µg/L Highest in the ZIP: LA VERNE, CITY WD · 31,334 people · 2019 | 1/3 | SYR4 |
| TTHM | 63.38 µg/L 79% of the EPA limit 80 µg/L Main supplier: WALNUT VALLEY WATER DISTRICT · 100,941 people · 2019 | 3/3 | SYR4 |
| Lithium | 50.1 µg/L No EPA limit set Main supplier: WALNUT VALLEY WATER DISTRICT · 100,941 people · 2024
Highest in the ZIP: 57 µg/L — GSWC-SAN DIMAS · 56,538 people · 2025 | 2/3 | UCMR-5 |
| Total Haloacetic Acids (HAA5) | 33.34 µg/L 56% of the EPA limit 60 µg/L Main supplier: WALNUT VALLEY WATER DISTRICT · 100,941 people · 2019 | 3/3 | SYR4 |
| Chloroform | 18.585 µg/L No EPA limit set Main supplier: WALNUT VALLEY WATER DISTRICT · 100,941 people · 2019
Highest in the ZIP: 23 µg/L — GSWC-SAN DIMAS · 56,538 people · 2019 | 3/3 | SYR4 |
| Monochloroacetic Acid | 22.34 µg/L No EPA limit set Main supplier: WALNUT VALLEY WATER DISTRICT · 100,941 people · 2019 | 2/3 | SYR4 |
| Dibromochloromethane | 21.925 µg/L No EPA limit set Main supplier: WALNUT VALLEY WATER DISTRICT · 100,941 people · 2019
Highest in the ZIP: 22.25 µg/L — LA VERNE, CITY WD · 31,334 people · 2019 | 3/3 | SYR4 |
| Bromodichloromethane | 20.84 µg/L No EPA limit set Main supplier: WALNUT VALLEY WATER DISTRICT · 100,941 people · 2019 | 3/3 | SYR4 |
| Trichloroethylene | 16 µg/L 320% of the EPA limit, at the 95th percentile of samples — 5 µg/L Highest in the ZIP: LA VERNE, CITY WD · 31,334 people · 2019 | 1/3 | SYR4 |
| Bromoform | 9.06 µg/L No EPA limit set Main supplier: WALNUT VALLEY WATER DISTRICT · 100,941 people · 2019
Highest in the ZIP: 15.945 µg/L — LA VERNE, CITY WD · 31,334 people · 2019 | 3/3 | SYR4 |
| Dichloroacetic Acid | 13.385 µg/L No EPA limit set Main supplier: WALNUT VALLEY WATER DISTRICT · 100,941 people · 2019 | 3/3 | SYR4 |
| Trichloroacetic Acid | 8.942 µg/L No EPA limit set Main supplier: WALNUT VALLEY WATER DISTRICT · 100,941 people · 2019 | 3/3 | SYR4 |
| Dibromoacetic Acid | 8.1395 µg/L No EPA limit set Main supplier: WALNUT VALLEY WATER DISTRICT · 100,941 people · 2019 | 3/3 | SYR4 |
| Combined Uranium | 7.7778 µg/L 26% of the EPA limit 30 µg/L Highest in the ZIP: LA VERNE, CITY WD · 31,334 people · 2018 | 1/3 | SYR4 |
| Chromium | 6.12 µg/L 6.1% of the EPA limit 100 µg/L Highest in the ZIP: LA VERNE, CITY WD · 31,334 people · 2019 | 1/3 | SYR4 |
| Monobromoacetic Acid | 2.6945 µg/L No EPA limit set Main supplier: WALNUT VALLEY WATER DISTRICT · 100,941 people · 2019
Highest in the ZIP: 4.54 µg/L — LA VERNE, CITY WD · 31,334 people · 2019 | 2/3 | SYR4 |
| Arsenic | 3.36 µg/L 34% of the EPA limit 10 µg/L Highest in the ZIP: LA VERNE, CITY WD · 31,334 people · 2019 | 1/3 | SYR4 |
| 1,1-Dichloroethylene | 1.11 µg/L 16% of the EPA limit 7 µg/L Highest in the ZIP: LA VERNE, CITY WD · 31,334 people · 2019 | 1/3 | SYR4 |
| Tetrachloroethylene | 0.8675 µg/L 17% of the EPA limit 5 µg/L Highest in the ZIP: LA VERNE, CITY WD · 31,334 people · 2019 | 1/3 | SYR4 |
| Dichloromethane | 0.7700 µg/L 15% of the EPA limit 5 µg/L Highest in the ZIP: LA VERNE, CITY WD · 31,334 people · 2019 | 1/3 | SYR4 |
| 1,2-DIBROMO-3-CHLOROPROPANE | 0.0503 µg/L 25% of the EPA limit 0.2000 µg/L Highest in the ZIP: LA VERNE, CITY WD · 31,334 people · 2019 | 1/3 | SYR4 |
| Lead | 0.0 mg/L 0% of the EPA limit 0.0150 mg/L Main supplier: WALNUT VALLEY WATER DISTRICT · 100,941 people · 2024
Highest in the ZIP: 0.0090 mg/L — LA VERNE, CITY WD · 31,334 people · 2024 | 3/3 | LCR |
| PFOS | 0.0045 µg/L No EPA limit set Highest in the ZIP: GSWC-SAN DIMAS · 56,538 people · 2025 | 1/3 | 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 91750
| Supplier | State | Population served |
|---|---|---|
| WALNUT VALLEY WATER DISTRICT | CA | 100,941 |
| GSWC-SAN DIMAS | CA | 56,538 |
| LA VERNE, CITY WD | CA | 31,334 |
Frequently asked questions about ZIP 91750 tap water
Is the tap water in ZIP 91750 safe to drink?
EPA testing detected 25 contaminants across the water suppliers serving ZIP 91750. 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 91750?
3 public water suppliers report EPA drinking-water monitoring for ZIP 91750. Each is listed above with its population served.
What contaminants are in ZIP 91750's water?
EPA monitoring detected Nitrate, Fluoride, Barium, TTHM, Lithium, and others across this ZIP's suppliers. The full list with levels and sources is above.