What was found in ZIP 91377
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 | 50.48 µg/L 63% of the EPA limit 80 µg/L Main supplier: CALIFORNIA WATER SERVICE CO - WESTLAKE · 19,533 people · 2019 | 2/2 | SYR4 |
| Dibromochloromethane | 19.692 µg/L No EPA limit set Main supplier: CALIFORNIA WATER SERVICE CO - WESTLAKE · 19,533 people · 2019 | 2/2 | SYR4 |
| Bromoform | 17.182 µg/L No EPA limit set Main supplier: CALIFORNIA WATER SERVICE CO - WESTLAKE · 19,533 people · 2019 | 2/2 | SYR4 |
| Total Haloacetic Acids (HAA5) | 16 µg/L 27% of the EPA limit 60 µg/L Main supplier: CALIFORNIA WATER SERVICE CO - WESTLAKE · 19,533 people · 2019 | 2/2 | SYR4 |
| Monochloroacetic Acid | 4.8 µg/L No EPA limit set Main supplier: CALIFORNIA WATER SERVICE CO - WESTLAKE · 19,533 people · 2019
Highest in the ZIP: 15.535 µg/L — TRIUNFO WATER & SANITATION DISTRICT · 13,898 people · 2019 | 2/2 | SYR4 |
| Lithium | 13.8 µg/L No EPA limit set Main supplier: CALIFORNIA WATER SERVICE CO - WESTLAKE · 19,533 people · 2024 | 2/2 | UCMR-5 |
| Trichloroacetic Acid | 9.66 µg/L No EPA limit set Main supplier: CALIFORNIA WATER SERVICE CO - WESTLAKE · 19,533 people · 2019 | 2/2 | SYR4 |
| Bromodichloromethane | 8.9 µg/L No EPA limit set Main supplier: CALIFORNIA WATER SERVICE CO - WESTLAKE · 19,533 people · 2019 | 2/2 | SYR4 |
| Dibromoacetic Acid | 8.82 µg/L No EPA limit set Main supplier: CALIFORNIA WATER SERVICE CO - WESTLAKE · 19,533 people · 2019 | 2/2 | SYR4 |
| Dichloroacetic Acid | 5.91 µg/L No EPA limit set Main supplier: CALIFORNIA WATER SERVICE CO - WESTLAKE · 19,533 people · 2019 | 2/2 | SYR4 |
| Chloroform | 5.4 µg/L No EPA limit set Main supplier: CALIFORNIA WATER SERVICE CO - WESTLAKE · 19,533 people · 2019
Highest in the ZIP: 5.56 µg/L — TRIUNFO WATER & SANITATION DISTRICT · 13,898 people · 2019 | 2/2 | SYR4 |
| Monobromoacetic Acid | 3.14 µg/L No EPA limit set Main supplier: CALIFORNIA WATER SERVICE CO - WESTLAKE · 19,533 people · 2019 | 2/2 | SYR4 |
| Lead | 0.0030 mg/L 20% of the EPA limit 0.0150 mg/L Main supplier: CALIFORNIA WATER SERVICE CO - WESTLAKE · 19,533 people · 2024 | 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 91377
| Supplier | State | Population served |
|---|---|---|
| CALIFORNIA WATER SERVICE CO - WESTLAKE | CA | 19,533 |
| TRIUNFO WATER & SANITATION DISTRICT | CA | 13,898 |
Frequently asked questions about ZIP 91377 tap water
Is the tap water in ZIP 91377 safe to drink?
EPA testing detected 13 contaminants across the water suppliers serving ZIP 91377. 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 91377?
2 public water suppliers report EPA drinking-water monitoring for ZIP 91377. Each is listed above with its population served.
What contaminants are in ZIP 91377's water?
EPA monitoring detected TTHM, Dibromochloromethane, Bromoform, Total Haloacetic Acids (HAA5), Monochloroacetic Acid, and others across this ZIP's suppliers. The full list with levels and sources is above.