What was found in ZIP 91773
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 |
|---|---|---|---|
| TTHM | 59.65 µg/L 75% of the EPA limit 80 µg/L Main supplier: GSWC-SAN DIMAS · 56,538 people · 2019 | 1/1 | SYR4 |
| Lithium | 57 µg/L No EPA limit set Main supplier: GSWC-SAN DIMAS · 56,538 people · 2025 | 1/1 | UCMR-5 |
| Chloroform | 23 µg/L No EPA limit set Main supplier: GSWC-SAN DIMAS · 56,538 people · 2019 | 1/1 | SYR4 |
| Total Haloacetic Acids (HAA5) | 23 µg/L 38% of the EPA limit 60 µg/L Main supplier: GSWC-SAN DIMAS · 56,538 people · 2019 | 1/1 | SYR4 |
| Dibromochloromethane | 22 µg/L No EPA limit set Main supplier: GSWC-SAN DIMAS · 56,538 people · 2019 | 1/1 | SYR4 |
| Bromodichloromethane | 20 µg/L No EPA limit set Main supplier: GSWC-SAN DIMAS · 56,538 people · 2019 | 1/1 | SYR4 |
| Bromoform | 12 µg/L No EPA limit set Main supplier: GSWC-SAN DIMAS · 56,538 people · 2019 | 1/1 | SYR4 |
| Dichloroacetic Acid | 12 µg/L No EPA limit set Main supplier: GSWC-SAN DIMAS · 56,538 people · 2019 | 1/1 | SYR4 |
| Trichloroacetic Acid | 8.845 µg/L No EPA limit set Main supplier: GSWC-SAN DIMAS · 56,538 people · 2019 | 1/1 | SYR4 |
| Dibromoacetic Acid | 7.405 µg/L No EPA limit set Main supplier: GSWC-SAN DIMAS · 56,538 people · 2019 | 1/1 | SYR4 |
| PFOS | 0.0045 µg/L No EPA limit set Main supplier: GSWC-SAN DIMAS · 56,538 people · 2025 | 1/1 | UCMR-5 |
| Lead | 0.0021 mg/L 14% of the EPA limit 0.0150 mg/L Main supplier: GSWC-SAN DIMAS · 56,538 people · 2026 | 1/1 | 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 91773
| Supplier | State | Population served |
|---|---|---|
| GSWC-SAN DIMAS | CA | 56,538 |
Frequently asked questions about ZIP 91773 tap water
Is the tap water in ZIP 91773 safe to drink?
EPA testing detected 12 contaminants across the water suppliers serving ZIP 91773. 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 91773?
1 public water supplier report EPA drinking-water monitoring for ZIP 91773. Each is listed above with its population served.
What contaminants are in ZIP 91773's water?
EPA monitoring detected TTHM, Lithium, Chloroform, Total Haloacetic Acids (HAA5), Dibromochloromethane, and others across this ZIP's suppliers. The full list with levels and sources is above.