What was found in ZIP 94002
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 |
|---|---|---|---|
| Copper | 228.32 µg/L 18% of the EPA limit 1300 µg/L Main supplier: CALIFORNIA WATER SERVICE - SAN MATEO · 102,348 people · 2019 | 1/3 | SYR4 |
| TTHM | 53 µg/L 66% of the EPA limit 80 µg/L Main supplier: CALIFORNIA WATER SERVICE - SAN MATEO · 102,348 people · 2019
Highest in the ZIP: 63.38 µg/L — MID-PENINSULA WATER DISTRICT · 30,609 people · 2019 | 3/3 | SYR4 |
| Chloroform | 51.043 µg/L No EPA limit set Main supplier: CALIFORNIA WATER SERVICE - SAN MATEO · 102,348 people · 2019
Highest in the ZIP: 60.605 µg/L — MID-PENINSULA WATER DISTRICT · 30,609 people · 2019 | 3/3 | SYR4 |
| Total Haloacetic Acids (HAA5) | 54.2 µg/L 90% of the EPA limit 60 µg/L Main supplier: CALIFORNIA WATER SERVICE - SAN MATEO · 102,348 people · 2019
Highest in the ZIP: 54.3 µg/L — CALIFORNIA WATER SERVICE - SAN CARLOS · 35,344 people · 2019 | 3/3 | SYR4 |
| Dichloroacetic Acid | 31 µg/L No EPA limit set Main supplier: CALIFORNIA WATER SERVICE - SAN MATEO · 102,348 people · 2019 | 3/3 | SYR4 |
| Trichloroacetic Acid | 25 µg/L No EPA limit set Main supplier: CALIFORNIA WATER SERVICE - SAN MATEO · 102,348 people · 2019 | 3/3 | SYR4 |
| Lead | 14.656 µg/L 98% of the EPA limit 15 µg/L Main supplier: CALIFORNIA WATER SERVICE - SAN MATEO · 102,348 people · 2019 | 1/3 | SYR4 |
| Monochloroacetic Acid | 3 µg/L No EPA limit set Main supplier: CALIFORNIA WATER SERVICE - SAN MATEO · 102,348 people · 2019
Highest in the ZIP: 9.26 µg/L — CALIFORNIA WATER SERVICE - SAN CARLOS · 35,344 people · 2019 | 3/3 | SYR4 |
| Bromodichloromethane | 7.486 µg/L No EPA limit set Main supplier: CALIFORNIA WATER SERVICE - SAN MATEO · 102,348 people · 2019
Highest in the ZIP: 7.523 µg/L — CALIFORNIA WATER SERVICE - SAN CARLOS · 35,344 people · 2019 | 3/3 | SYR4 |
| Dibromochloromethane | 3.54 µg/L No EPA limit set Main supplier: CALIFORNIA WATER SERVICE - SAN MATEO · 102,348 people · 2019 | 3/3 | SYR4 |
| Bromoform | 3.406 µg/L No EPA limit set Main supplier: CALIFORNIA WATER SERVICE - SAN MATEO · 102,348 people · 2019 | 2/3 | SYR4 |
| Dibromoacetic Acid | 2.12 µg/L No EPA limit set Main supplier: CALIFORNIA WATER SERVICE - SAN MATEO · 102,348 people · 2019 | 2/3 | SYR4 |
| Monobromoacetic Acid | 1.1 µg/L No EPA limit set Main supplier: CALIFORNIA WATER SERVICE - SAN MATEO · 102,348 people · 2019 | 2/3 | SYR4 |
| Lead | 0.0044 mg/L 29% of the EPA limit 0.0150 mg/L Main supplier: CALIFORNIA WATER SERVICE - SAN MATEO · 102,348 people · 2025
Highest in the ZIP: 0.0058 mg/L — CALIFORNIA WATER SERVICE - SAN CARLOS · 35,344 people · 2024 | 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 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 94002
| Supplier | State | Population served |
|---|---|---|
| CALIFORNIA WATER SERVICE - SAN MATEO | CA | 102,348 |
| CALIFORNIA WATER SERVICE - SAN CARLOS | CA | 35,344 |
| MID-PENINSULA WATER DISTRICT | CA | 30,609 |
Frequently asked questions about ZIP 94002 tap water
Is the tap water in ZIP 94002 safe to drink?
EPA testing detected 14 contaminants across the water suppliers serving ZIP 94002. 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 94002?
3 public water suppliers report EPA drinking-water monitoring for ZIP 94002. Each is listed above with its population served.
What contaminants are in ZIP 94002's water?
EPA monitoring detected Copper, TTHM, Chloroform, Total Haloacetic Acids (HAA5), Dichloroacetic Acid, and others across this ZIP's suppliers. The full list with levels and sources is above.