What was found in ZIP 91789
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 | 12000 µg/L 120% of the EPA limit, in the worst sample — 10000 µg/L | 1/3 | SYR4 |
| Nitrate-Nitrite | 5900 µg/L 59% of the EPA limit 10000 µg/L | 1/3 | SYR4 |
| Fluoride | 490 µg/L 12% of the EPA limit 4000 µg/L | 1/3 | SYR4 |
| Barium | 150 µg/L 7.5% of the EPA limit 2000 µg/L | 1/3 | SYR4 |
| TTHM | 120 µg/L 150% of the EPA limit, in the worst sample — 80 µg/L | 3/3 | SYR4 |
| Lithium | 57 µg/L No EPA limit set | 3/3 | UCMR-5 |
| Chloroform | 48 µg/L No EPA limit set | 3/3 | SYR4 |
| Dibromochloromethane | 46 µg/L No EPA limit set | 3/3 | SYR4 |
| Total Haloacetic Acids (HAA5) | 44.4 µg/L 74% of the EPA limit 60 µg/L | 3/3 | SYR4 |
| Bromodichloromethane | 34 µg/L No EPA limit set | 3/3 | SYR4 |
| Bromoform | 34 µg/L No EPA limit set | 3/3 | SYR4 |
| Monochloroacetic Acid | 25.3 µg/L No EPA limit set | 1/3 | SYR4 |
| Dichloroacetic Acid | 21.1 µg/L No EPA limit set | 3/3 | SYR4 |
| Trichloroacetic Acid | 18.1 µg/L No EPA limit set | 3/3 | SYR4 |
| Chromium | 17 µg/L 17% of the EPA limit 100 µg/L | 1/3 | SYR4 |
| Dibromoacetic Acid | 17 µg/L No EPA limit set | 3/3 | SYR4 |
| 1,1-Dichloroethylene | 16 µg/L 229% of the EPA limit, in the worst sample — 7 µg/L | 1/3 | SYR4 |
| Trichloroethylene | 14 µg/L 280% of the EPA limit, in the worst sample — 5 µg/L | 1/3 | SYR4 |
| Tetrachloroethylene | 7.8 µg/L 156% of the EPA limit, in the worst sample — 5 µg/L | 1/3 | SYR4 |
| Monobromoacetic Acid | 4.16 µg/L No EPA limit set | 1/3 | SYR4 |
| Arsenic | 2.5 µg/L 25% of the EPA limit 10 µg/L | 1/3 | SYR4 |
| Combined Uranium | 2.235 µg/L 7.5% of the EPA limit 30 µg/L | 1/3 | SYR4 |
| Chlorobenzene | 1.4 µg/L 1.4% of the EPA limit 100 µg/L | 1/3 | SYR4 |
| trans-1,2-Dichloroethylene | 1.3 µg/L 1.3% of the EPA limit 100 µg/L | 1/3 | SYR4 |
| cis-1,2-Dichloroethylene | 1.2 µg/L 1.7% of the EPA limit 70 µg/L | 1/3 | SYR4 |
| Carbon Tetrachloride | 0.6700 µg/L 13% of the EPA limit 5 µg/L | 1/3 | SYR4 |
| Pfba | 0.0062 µg/L No EPA limit set | 1/3 | UCMR-5 |
| PFOS | 0.0045 µg/L No EPA limit set | 1/3 | UCMR-5 |
| PFBS | 0.0036 µg/L No EPA limit set | 1/3 | UCMR-5 |
| Pfpea | 0.0035 µg/L No EPA limit set | 1/3 | UCMR-5 |
| Pfhxa | 0.0033 µg/L No EPA limit set | 1/3 | UCMR-5 |
| Lead | 0.0021 mg/L 14% of the EPA limit 0.0150 mg/L | 3/3 | 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 91789
| Supplier | State | Population served |
|---|---|---|
| SUBURBAN WATER SYSTEMS-SAN JOSE | CA | 168,843 |
| WALNUT VALLEY WATER DISTRICT | CA | 100,941 |
| GSWC-SAN DIMAS | CA | 56,538 |
Frequently asked questions about ZIP 91789 tap water
Is the tap water in ZIP 91789 safe to drink?
EPA testing detected 32 contaminants across the water suppliers serving ZIP 91789. 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 91789?
3 public water suppliers report EPA drinking-water monitoring for ZIP 91789. Each is listed above with its population served.
What contaminants are in ZIP 91789's water?
EPA monitoring detected Nitrate, Nitrate-Nitrite, Fluoride, Barium, TTHM, and others across this ZIP's suppliers. The full list with levels and sources is above.