What was found in ZIP 91770
The highest level seen across the suppliers serving this ZIP, the EPA limit for each, and where the figure comes from.
| Contaminant | Level vs EPA limit | Suppliers | Source |
|---|---|---|---|
| Nitrate-Nitrite | 580000 µg/L 5800% of the EPA limit, in the worst sample — 10000 µg/L | 3/4 | SYR4 |
| Nitrate | 22000 µg/L 220% of the EPA limit, in the worst sample — 10000 µg/L | 3/4 | SYR4 |
| Fluoride | 1700 µg/L 43% of the EPA limit 4000 µg/L | 3/4 | SYR4 |
| Barium | 220 µg/L 11% of the EPA limit 2000 µg/L | 1/4 | SYR4 |
| Tetrachloroethylene | 220 µg/L 4400% of the EPA limit, in the worst sample — 5 µg/L | 3/4 | SYR4 |
| Copper | 190 µg/L 15% of the EPA limit 1300 µg/L | 3/4 | SYR4 |
| Trichloroethylene | 140 µg/L 2800% of the EPA limit, in the worst sample — 5 µg/L | 3/4 | SYR4 |
| Lithium | 91.9 µg/L No EPA limit set | 2/4 | UCMR-5 |
| 1,1-Dichloroethylene | 64 µg/L 914% of the EPA limit, in the worst sample — 7 µg/L | 1/4 | SYR4 |
| Chromium | 44 µg/L 44% of the EPA limit 100 µg/L | 1/4 | SYR4 |
| TTHM | 43 µg/L 54% of the EPA limit 80 µg/L | 4/4 | SYR4 |
| Total Haloacetic Acids (HAA5) | 29 µg/L 48% of the EPA limit 60 µg/L | 4/4 | SYR4 |
| Combined Uranium | 23.84 µg/L 79% of the EPA limit 30 µg/L | 3/4 | SYR4 |
| trans-1,2-Dichloroethylene | 23 µg/L 23% of the EPA limit 100 µg/L | 1/4 | SYR4 |
| Dibromochloromethane | 17.2 µg/L No EPA limit set | 4/4 | SYR4 |
| Bromodichloromethane | 17.1 µg/L No EPA limit set | 4/4 | SYR4 |
| Carbon Tetrachloride | 17 µg/L 340% of the EPA limit, in the worst sample — 5 µg/L | 2/4 | SYR4 |
| Lead | 17 µg/L 113% of the EPA limit, in the worst sample — 15 µg/L | 2/4 | SYR4 |
| Chloroform | 15.9 µg/L No EPA limit set | 4/4 | SYR4 |
| Trichloroacetic Acid | 13 µg/L No EPA limit set | 2/4 | SYR4 |
| Dichloroacetic Acid | 12 µg/L No EPA limit set | 2/4 | SYR4 |
| Bromoform | 8.2 µg/L No EPA limit set | 4/4 | SYR4 |
| cis-1,2-Dichloroethylene | 6.1 µg/L 8.7% of the EPA limit 70 µg/L | 2/4 | SYR4 |
| Gross Beta Particle Activity | 5.8 pCi/L No EPA limit set | 1/4 | SYR4 |
| Selenium | 5 µg/L 10% of the EPA limit 50 µg/L | 1/4 | SYR4 |
| Dibromoacetic Acid | 4.8 µg/L No EPA limit set | 4/4 | SYR4 |
| Arsenic | 4.5 µg/L 45% of the EPA limit 10 µg/L | 3/4 | SYR4 |
| 1,1,2-Trichloroethane | 3.8 µg/L 76% of the EPA limit 5 µg/L | 1/4 | SYR4 |
| 1,2-Dichloroethane | 3.7 µg/L 74% of the EPA limit 5 µg/L | 1/4 | SYR4 |
| Monochloroacetic Acid | 3 µg/L No EPA limit set | 3/4 | SYR4 |
| 1,2-Dichloropropane | 2.9 µg/L 58% of the EPA limit 5 µg/L | 1/4 | SYR4 |
| Mercury | 2.1 µg/L 105% of the EPA limit, in the worst sample — 2 µg/L | 1/4 | SYR4 |
| Pentachlorophenol | 0.8500 µg/L 85% of the EPA limit 1 µg/L | 1/4 | SYR4 |
| Toluene | 0.5200 µg/L 0.1% of the EPA limit 1000 µg/L | 1/4 | SYR4 |
| Nitrite | 0.4700 µg/L 0% of the EPA limit 1000 µg/L | 1/4 | SYR4 |
| Pfba | 0.0100 µg/L No EPA limit set | 3/4 | UCMR-5 |
| Pfpea | 0.0056 µg/L No EPA limit set | 1/4 | UCMR-5 |
| Lead | 0.0 mg/L 0% of the EPA limit 0.0150 mg/L | 4/4 | 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 single worst sample on
record — over 100% is worth reading, but is not by itself a violation.
Formal violations are listed separately.
Water suppliers serving ZIP 91770
| Supplier | State | Population served |
|---|---|---|
| SAN GABRIEL VALLEY WATER CO.-EL MONTE | CA | 248,000 |
| CAL/AM WATER COMPANY - SAN MARINO | CA | 47,995 |
| SAN GABRIEL COUNTY WD | CA | 39,345 |
| GSWC-SOUTH SAN GABRIEL | CA | 26,240 |
Frequently asked questions about ZIP 91770 tap water
Is the tap water in ZIP 91770 safe to drink?
EPA testing detected 38 contaminants across the water suppliers serving ZIP 91770. 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 91770?
4 public water suppliers report EPA drinking-water monitoring for ZIP 91770. Each is listed above with its population served.
What contaminants are in ZIP 91770's water?
EPA monitoring detected Nitrate-Nitrite, Nitrate, Fluoride, Barium, Tetrachloroethylene, and others across this ZIP's suppliers. The full list with levels and sources is above.