What was found in San Jose's water
The level at the city's main supplier, the highest level anywhere in the city, the EPA limit for each, and where every figure comes from.
| Contaminant | Level vs EPA limit | Suppliers | Source |
|---|---|---|---|
| Nitrate-Nitrite | 660000 µg/L 6600% of the EPA limit, at the 95th percentile of samples — 10000 µg/L Main supplier: SAN JOSE WATER · 1,039,920 people · 2019
Highest in the city: 838000 µg/L — GREAT OAKS WC INC · 110,088 people · 2019 | 7/11 | SYR4 |
| Nitrate | 6102 µg/L 61% of the EPA limit 10000 µg/L Main supplier: SAN JOSE WATER · 1,039,920 people · 2019
Highest in the city: 8895 µg/L — ABORN HEIGHTS WATER MUTUAL ASSOCIATION · 45 people · 2019 | 8/11 | SYR4 |
| Fluoride | 422 µg/L 11% of the EPA limit 4000 µg/L Main supplier: SAN JOSE WATER · 1,039,920 people · 2019
Highest in the city: 705.5 µg/L — SANTA CLARA VALLEY WATER DISTRICT · 0 people · 2019 | 8/11 | SYR4 |
| Copper | 342.085 µg/L 26% of the EPA limit 1300 µg/L Main supplier: SAN JOSE WATER · 1,039,920 people · 2019 | 3/11 | SYR4 |
| Barium | 290 µg/L 14% of the EPA limit 2000 µg/L Main supplier: SAN JOSE WATER · 1,039,920 people · 2019 | 7/11 | SYR4 |
| TTHM | 76.7125 µg/L 96% of the EPA limit 80 µg/L Main supplier: SAN JOSE WATER · 1,039,920 people · 2019 | 11/11 | SYR4 |
| Chloroform | 58.527 µg/L No EPA limit set Main supplier: SAN JOSE WATER · 1,039,920 people · 2019
Highest in the city: 60.929 µg/L — CITY OF SAN JOSE - NSJ/ALVISO · 45,559 people · 2019 | 9/11 | SYR4 |
| Total Haloacetic Acids (HAA5) | 51.115 µg/L 85% of the EPA limit 60 µg/L Main supplier: SAN JOSE WATER · 1,039,920 people · 2019
Highest in the city: 52.515 µg/L — CITY OF SAN JOSE - NSJ/ALVISO · 45,559 people · 2019 | 11/11 | SYR4 |
| Trichloroacetic Acid | 32.06 µg/L No EPA limit set Main supplier: SAN JOSE WATER · 1,039,920 people · 2019 | 8/11 | SYR4 |
| Dichloroacetic Acid | 22.24 µg/L No EPA limit set Main supplier: SAN JOSE WATER · 1,039,920 people · 2019
Highest in the city: 30.22 µg/L — CITY OF SAN JOSE - NSJ/ALVISO · 45,559 people · 2019 | 9/11 | SYR4 |
| Chromium | 27.2 µg/L 27% of the EPA limit 100 µg/L Main supplier: SAN JOSE WATER · 1,039,920 people · 2019 | 5/11 | SYR4 |
| Dibromochloromethane | 25.1265 µg/L No EPA limit set Main supplier: SAN JOSE WATER · 1,039,920 people · 2019
Highest in the city: 26.3 µg/L — SANTA CLARA VALLEY WATER DISTRICT · 0 people · 2019 | 10/11 | SYR4 |
| Bromoform | 21.152 µg/L No EPA limit set Main supplier: SAN JOSE WATER · 1,039,920 people · 2019
Highest in the city: 24.33 µg/L — CITY OF SAN JOSE - EVG/EDV/COY · 101,265 people · 2019 | 11/11 | SYR4 |
| Bromodichloromethane | 16.962 µg/L No EPA limit set Main supplier: SAN JOSE WATER · 1,039,920 people · 2019
Highest in the city: 19.558 µg/L — CWSC LOS ALTOS SUBURBAN · 69,973 people · 2019 | 10/11 | SYR4 |
| Lead | 16.04 µg/L 107% of the EPA limit, at the 95th percentile of samples — 15 µg/L Main supplier: SAN JOSE WATER · 1,039,920 people · 2019 | 3/11 | SYR4 |
| Lithium | 10 µg/L No EPA limit set Main supplier: SAN JOSE WATER · 1,039,920 people · 2025
Highest in the city: 16 µg/L — CWSC KING CITY · 16,334 people · 2025 | 5/11 | UCMR-5 |
| Selenium | 9 µg/L 18% of the EPA limit 50 µg/L Main supplier: SAN JOSE WATER · 1,039,920 people · 2019
Highest in the city: 12.9 µg/L — SANTA CLARA VALLEY WATER DISTRICT · 0 people · 2019 | 6/11 | SYR4 |
| Dibromoacetic Acid | 12.62 µg/L No EPA limit set Main supplier: SAN JOSE WATER · 1,039,920 people · 2019 | 11/11 | SYR4 |
| Monochloroacetic Acid | 6.88 µg/L No EPA limit set Main supplier: SAN JOSE WATER · 1,039,920 people · 2019
Highest in the city: 12.035 µg/L — SANTA CLARA VALLEY WATER DISTRICT · 0 people · 2019 | 4/11 | SYR4 |
| Bromate | 5.746 µg/L 57% of the EPA limit 10 µg/L Highest in the city: SANTA CLARA VALLEY WATER DISTRICT · 0 people · 2019 | 1/11 | SYR4 |
| Arsenic | 5.5 µg/L 55% of the EPA limit 10 µg/L Main supplier: SAN JOSE WATER · 1,039,920 people · 2019 | 6/11 | SYR4 |
| 1,1-Dichloroethylene | 5.46 µg/L 78% of the EPA limit 7 µg/L Main supplier: SAN JOSE WATER · 1,039,920 people · 2019 | 1/11 | SYR4 |
| Gross Beta Particle Activity | 5.25 pCi/L No EPA limit set Main supplier: SAN JOSE WATER · 1,039,920 people · 2019 | 3/11 | SYR4 |
| 1,1,1-Trichloroethane | 3.2 µg/L 1.6% of the EPA limit 200 µg/L Main supplier: SAN JOSE WATER · 1,039,920 people · 2019 | 4/11 | SYR4 |
| Combined Uranium | 2.71553 µg/L 9.1% of the EPA limit 30 µg/L Main supplier: SAN JOSE WATER · 1,039,920 people · 2019 | 5/11 | SYR4 |
| Combined Radium (-226 And -228) | 2.303 pCi/L 46% of the EPA limit 5 pCi/L Main supplier: SAN JOSE WATER · 1,039,920 people · 2019 | 1/11 | SYR4 |
| Monobromoacetic Acid | 1.845 µg/L No EPA limit set Main supplier: SAN JOSE WATER · 1,039,920 people · 2019
Highest in the city: 2.22 µg/L — CITY OF SAN JOSE - EVG/EDV/COY · 101,265 people · 2019 | 4/11 | SYR4 |
| Mercury | 1.9 µg/L 95% of the EPA limit 2 µg/L Highest in the city: GREAT OAKS WC INC · 110,088 people · 2019 | 1/11 | SYR4 |
| Asbestos | 0.2000 MFL 2.9% of the EPA limit 7 MFL Main supplier: SAN JOSE WATER · 1,039,920 people · 2019
Highest in the city: 0.7000 MFL — CITY OF SAN JOSE - NSJ/ALVISO · 45,559 people · 2017 | 4/11 | SYR4 |
| Styrene | 0.6900 µg/L 0.7% of the EPA limit 100 µg/L Main supplier: SAN JOSE WATER · 1,039,920 people · 2019 | 1/11 | SYR4 |
| Di(2-ethylhexyl) Phthalate | 0.2900 µg/L 4.8% of the EPA limit 6 µg/L Main supplier: SAN JOSE WATER · 1,039,920 people · 2019 | 1/11 | SYR4 |
| Di(2-ethylhexyl) Adipate | 0.2200 µg/L 0.1% of the EPA limit 400 µg/L Main supplier: SAN JOSE WATER · 1,039,920 people · 2019 | 1/11 | SYR4 |
| Antimony, Total | 0.1070 µg/L 1.8% of the EPA limit 6 µg/L Highest in the city: CWSC KING CITY · 16,334 people · 2019 | 2/11 | SYR4 |
| Cadmium | 0.0451 µg/L 0.9% of the EPA limit 5 µg/L Highest in the city: CWSC KING CITY · 16,334 people · 2019 | 2/11 | SYR4 |
| PFHXS | 0.0055 µg/L No EPA limit set Main supplier: SAN JOSE WATER · 1,039,920 people · 2025
Highest in the city: 0.0080 µg/L — GREAT OAKS WC INC · 110,088 people · 2025 | 3/11 | UCMR-5 |
| Thallium, Total | 0.0080 µg/L 0.4% of the EPA limit 2 µg/L Highest in the city: CWSC LOS ALTOS SUBURBAN · 69,973 people · 2019 | 1/11 | SYR4 |
| Lead | 0.0 mg/L 0% of the EPA limit 0.0150 mg/L Main supplier: SAN JOSE WATER · 1,039,920 people · 2025
Highest in the city: 0.0076 mg/L — ABORN HEIGHTS WATER MUTUAL ASSOCIATION · 45 people · 2025 | 10/11 | LCR |
| PFOS | 0.0062 µg/L No EPA limit set Main supplier: SAN JOSE WATER · 1,039,920 people · 2025 | 2/11 | UCMR-5 |
| Pfpea | 0.0047 µg/L No EPA limit set Highest in the city: GREAT OAKS WC INC · 110,088 people · 2025 | 1/11 | UCMR-5 |
| Pfhxa | 0.0045 µg/L No EPA limit set Highest in the city: GREAT OAKS WC INC · 110,088 people · 2025 | 1/11 | UCMR-5 |
| Beryllium, Total | 0.0020 µg/L 0.1% of the EPA limit 4 µg/L Highest in the city: CWSC LOS ALTOS SUBURBAN · 69,973 people · 2019 | 1/11 | SYR4 |
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.
These are the utilities' own EPA-reported results, not a city-wide
average. A detection means the lab measured the
substance — it isn't the same as exceeding a legal limit. Hover a source
tag to see the EPA program and years behind each figure.
Water suppliers serving San Jose
| Supplier | Population served |
|---|---|
| SAN JOSE WATER | 1,039,920 |
| GREAT OAKS WC INC | 110,088 |
| CITY OF SAN JOSE - EVG/EDV/COY | 101,265 |
| CWSC LOS ALTOS SUBURBAN | 69,973 |
| CITY OF SAN JOSE - NSJ/ALVISO | 45,559 |
| CWSC KING CITY | 16,334 |
| MT. PLEASANT WATER USERS ASSOCIATION | 300 |
| ROSEVIEW HEIGHTS MUTUAL WATER COMPANY | 148 |
| KENNON WATER COMPANY | 142 |
| ABORN HEIGHTS WATER MUTUAL ASSOCIATION | 45 |
| SANTA CLARA VALLEY WATER DISTRICT | 0 |
Frequently asked questions about San Jose tap water
Is San Jose tap water safe to drink?
EPA testing detected 41 contaminants in the water serving San Jose. A detection isn't the same as a violation — most detected levels are within federal limits. Check the level and source for each contaminant above, and your utility's annual Consumer Confidence Report for the official compliance status.
How many water suppliers serve San Jose?
11 public water suppliers report drinking-water monitoring for San Jose, California to the EPA. Each is listed above with its population served.
What contaminants are in San Jose's water?
The contaminants EPA monitoring detected in San Jose include Nitrate-Nitrite, Nitrate, Fluoride, Copper, Barium. The full list, with the level at the main supplier and the data source, is in the table above.
Where does this data come from?
Every figure is official EPA drinking-water monitoring — the Lead & Copper Rule, the UCMR-5 nationwide testing program, and the EPA Six-Year Review — not our own testing. Each number is labelled with its source and period.