What was found in ZIP 94597
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 |
|---|---|---|---|
| Nitrate-Nitrite | 534000 µg/L 5340% of the EPA limit, at the 95th percentile of samples — 10000 µg/L Main supplier: EAST BAY MUD · 1,442,800 people · 2019 | 2/2 | SYR4 |
| Nitrate | 549.18 µg/L 5.5% of the EPA limit 10000 µg/L Main supplier: EAST BAY MUD · 1,442,800 people · 2019
Highest in the ZIP: 1288.2 µg/L — CONTRA COSTA WATER DISTRICT · 198,000 people · 2019 | 2/2 | SYR4 |
| Fluoride | 900 µg/L 23% of the EPA limit 4000 µg/L Main supplier: EAST BAY MUD · 1,442,800 people · 2019 | 2/2 | SYR4 |
| Nitrite | 494.004 µg/L 49% of the EPA limit 1000 µg/L Highest in the ZIP: CONTRA COSTA WATER DISTRICT · 198,000 people · 2019 | 1/2 | SYR4 |
| Copper | 278 µg/L 21% of the EPA limit 1300 µg/L Highest in the ZIP: CONTRA COSTA WATER DISTRICT · 198,000 people · 2019 | 1/2 | SYR4 |
| Barium | 160 µg/L 8% of the EPA limit 2000 µg/L Highest in the ZIP: CONTRA COSTA WATER DISTRICT · 198,000 people · 2019 | 1/2 | SYR4 |
| Gross Beta Particle Activity | 3.1485 pCi/L No EPA limit set Main supplier: EAST BAY MUD · 1,442,800 people · 2019
Highest in the ZIP: 48.2 pCi/L — CONTRA COSTA WATER DISTRICT · 198,000 people · 2019 | 2/2 | SYR4 |
| TTHM | 39.3 µg/L 49% of the EPA limit 80 µg/L Highest in the ZIP: CONTRA COSTA WATER DISTRICT · 198,000 people · 2019 | 1/2 | SYR4 |
| Selenium | 37.15 µg/L 74% of the EPA limit 50 µg/L Highest in the ZIP: CONTRA COSTA WATER DISTRICT · 198,000 people · 2019 | 1/2 | SYR4 |
| Chromium | 12 µg/L 12% of the EPA limit 100 µg/L Main supplier: EAST BAY MUD · 1,442,800 people · 2019
Highest in the ZIP: 29 µg/L — CONTRA COSTA WATER DISTRICT · 198,000 people · 2019 | 2/2 | SYR4 |
| Dibromochloromethane | 14.1 µg/L No EPA limit set Highest in the ZIP: CONTRA COSTA WATER DISTRICT · 198,000 people · 2019 | 1/2 | SYR4 |
| Bromate | 13.3 µg/L 133% of the EPA limit, at the 95th percentile of samples — 10 µg/L Highest in the ZIP: CONTRA COSTA WATER DISTRICT · 198,000 people · 2019 | 1/2 | SYR4 |
| Bromodichloromethane | 11.6 µg/L No EPA limit set Highest in the ZIP: CONTRA COSTA WATER DISTRICT · 198,000 people · 2019 | 1/2 | SYR4 |
| Total Haloacetic Acids (HAA5) | 10.7 µg/L 18% of the EPA limit 60 µg/L Highest in the ZIP: CONTRA COSTA WATER DISTRICT · 198,000 people · 2019 | 1/2 | SYR4 |
| Chloroform | 9.74 µg/L No EPA limit set Highest in the ZIP: CONTRA COSTA WATER DISTRICT · 198,000 people · 2019 | 1/2 | SYR4 |
| Bromoform | 9.37 µg/L No EPA limit set Highest in the ZIP: CONTRA COSTA WATER DISTRICT · 198,000 people · 2019 | 1/2 | SYR4 |
| Lead | 6.6 µg/L 44% of the EPA limit 15 µg/L Main supplier: EAST BAY MUD · 1,442,800 people · 2019 | 2/2 | SYR4 |
| Dichloroacetic Acid | 6.275 µg/L No EPA limit set Highest in the ZIP: CONTRA COSTA WATER DISTRICT · 198,000 people · 2019 | 1/2 | SYR4 |
| Arsenic | 4.44 µg/L 44% of the EPA limit 10 µg/L Main supplier: EAST BAY MUD · 1,442,800 people · 2019
Highest in the ZIP: 5.845 µg/L — CONTRA COSTA WATER DISTRICT · 198,000 people · 2019 | 2/2 | SYR4 |
| Dibromoacetic Acid | 4.625 µg/L No EPA limit set Highest in the ZIP: CONTRA COSTA WATER DISTRICT · 198,000 people · 2019 | 1/2 | SYR4 |
| Trichloroacetic Acid | 3.36 µg/L No EPA limit set Highest in the ZIP: CONTRA COSTA WATER DISTRICT · 198,000 people · 2019 | 1/2 | SYR4 |
| Dichloromethane | 2.98 µg/L 60% of the EPA limit 5 µg/L Highest in the ZIP: CONTRA COSTA WATER DISTRICT · 198,000 people · 2019 | 1/2 | SYR4 |
| Monobromoacetic Acid | 2.52 µg/L No EPA limit set Highest in the ZIP: CONTRA COSTA WATER DISTRICT · 198,000 people · 2019 | 1/2 | SYR4 |
| Cadmium | 1.595 µg/L 32% of the EPA limit 5 µg/L Highest in the ZIP: CONTRA COSTA WATER DISTRICT · 198,000 people · 2019 | 1/2 | SYR4 |
| Cyanide | 1.57 µg/L 0.8% of the EPA limit 200 µg/L Highest in the ZIP: CONTRA COSTA WATER DISTRICT · 198,000 people · 2019 | 1/2 | SYR4 |
| Combined Uranium | 1.25607 µg/L 4.2% of the EPA limit 30 µg/L Main supplier: EAST BAY MUD · 1,442,800 people · 2019
Highest in the ZIP: 1.39315 µg/L — CONTRA COSTA WATER DISTRICT · 198,000 people · 2019 | 2/2 | SYR4 |
| Asbestos | 1.08 MFL 15% of the EPA limit 7 MFL Main supplier: EAST BAY MUD · 1,442,800 people · 2019 | 2/2 | SYR4 |
| Di(2-ethylhexyl) Phthalate | 0.3845 µg/L 6.4% of the EPA limit 6 µg/L Highest in the ZIP: CONTRA COSTA WATER DISTRICT · 198,000 people · 2019 | 1/2 | SYR4 |
| Di(2-ethylhexyl) Adipate | 0.2100 µg/L 0.1% of the EPA limit 400 µg/L Highest in the ZIP: CONTRA COSTA WATER DISTRICT · 198,000 people · 2019 | 1/2 | SYR4 |
| Pfba | 0.0052 µg/L No EPA limit set Main supplier: EAST BAY MUD · 1,442,800 people · 2024 | 1/2 | UCMR-5 |
| Lead | 0.0 mg/L 0% of the EPA limit 0.0150 mg/L Main supplier: EAST BAY MUD · 1,442,800 people · 2024
Highest in the ZIP: 0.0031 mg/L — CONTRA COSTA WATER DISTRICT · 198,000 people · 2025 | 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 94597
| Supplier | State | Population served |
|---|---|---|
| EAST BAY MUD | CA | 1,442,800 |
| CONTRA COSTA WATER DISTRICT | CA | 198,000 |
Frequently asked questions about ZIP 94597 tap water
Is the tap water in ZIP 94597 safe to drink?
EPA testing detected 31 contaminants across the water suppliers serving ZIP 94597. 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 94597?
2 public water suppliers report EPA drinking-water monitoring for ZIP 94597. Each is listed above with its population served.
What contaminants are in ZIP 94597's water?
EPA monitoring detected Nitrate-Nitrite, Nitrate, Fluoride, Nitrite, Copper, and others across this ZIP's suppliers. The full list with levels and sources is above.