What was found in East Palo Alto'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 | 1356 µg/L 14% of the EPA limit 10000 µg/L Highest in the city: PALO ALTO PARK MUTUAL WATER COMPANY · 2,900 people · 2019 | 1/2 | SYR4 |
| Nitrate-Nitrite | 1039.9999999999998 µg/L 10% of the EPA limit 10000 µg/L Highest in the city: PALO ALTO PARK MUTUAL WATER COMPANY · 2,900 people · 2019 | 1/2 | SYR4 |
| Barium | 364.8 µg/L 18% of the EPA limit 2000 µg/L Main supplier: CITY OF EAST PALO ALTO · 29,519 people · 2019 | 2/2 | SYR4 |
| Fluoride | 117.89999999999999 µg/L 2.9% of the EPA limit 4000 µg/L Main supplier: CITY OF EAST PALO ALTO · 29,519 people · 2019
Highest in the city: 250.99999999999997 µg/L — PALO ALTO PARK MUTUAL WATER COMPANY · 2,900 people · 2019 | 2/2 | SYR4 |
| Cyanide | 220 µg/L 110% of the EPA limit, at the 95th percentile of samples — 200 µg/L Main supplier: CITY OF EAST PALO ALTO · 29,519 people · 2019 | 2/2 | SYR4 |
| TTHM | 63.01 µg/L 79% of the EPA limit 80 µg/L Main supplier: CITY OF EAST PALO ALTO · 29,519 people · 2019 | 2/2 | SYR4 |
| Chloroform | 62.25 µg/L No EPA limit set Main supplier: CITY OF EAST PALO ALTO · 29,519 people · 2019 | 1/2 | SYR4 |
| Total Haloacetic Acids (HAA5) | 51.69999999999999 µg/L 86% of the EPA limit 60 µg/L Main supplier: CITY OF EAST PALO ALTO · 29,519 people · 2019 | 1/2 | SYR4 |
| Trichloroacetic Acid | 26.959999999999994 µg/L No EPA limit set Main supplier: CITY OF EAST PALO ALTO · 29,519 people · 2019 | 1/2 | SYR4 |
| Dichloroacetic Acid | 25 µg/L No EPA limit set Main supplier: CITY OF EAST PALO ALTO · 29,519 people · 2019 | 1/2 | SYR4 |
| Copper | 20.599999999999998 µg/L 1.6% of the EPA limit 1300 µg/L Highest in the city: PALO ALTO PARK MUTUAL WATER COMPANY · 2,900 people · 2019 | 1/2 | SYR4 |
| Chromium | 11.525 µg/L 12% of the EPA limit 100 µg/L Highest in the city: PALO ALTO PARK MUTUAL WATER COMPANY · 2,900 people · 2019 | 1/2 | SYR4 |
| Bromodichloromethane | 6.1 µg/L No EPA limit set Main supplier: CITY OF EAST PALO ALTO · 29,519 people · 2019 | 2/2 | SYR4 |
| Selenium | 5.3 µg/L 11% of the EPA limit 50 µg/L Main supplier: CITY OF EAST PALO ALTO · 29,519 people · 2019 | 1/2 | SYR4 |
| Arsenic | 3.3 µg/L 33% of the EPA limit 10 µg/L Main supplier: CITY OF EAST PALO ALTO · 29,519 people · 2019
Highest in the city: 3.64 µg/L — PALO ALTO PARK MUTUAL WATER COMPANY · 2,900 people · 2019 | 2/2 | SYR4 |
| Monochloroacetic Acid | 3.4 µg/L No EPA limit set Main supplier: CITY OF EAST PALO ALTO · 29,519 people · 2019 | 1/2 | SYR4 |
| Bromoform | 0.5000 µg/L No EPA limit set Main supplier: CITY OF EAST PALO ALTO · 29,519 people · 2019
Highest in the city: 3.395 µg/L — PALO ALTO PARK MUTUAL WATER COMPANY · 2,900 people · 2017 | 2/2 | SYR4 |
| Monobromoacetic Acid | 3.26 µg/L No EPA limit set Main supplier: CITY OF EAST PALO ALTO · 29,519 people · 2019 | 1/2 | SYR4 |
| Lead | 2.3 µg/L 15% of the EPA limit 15 µg/L Highest in the city: PALO ALTO PARK MUTUAL WATER COMPANY · 2,900 people · 2014 | 1/2 | SYR4 |
| Gross Beta Particle Activity | 1.72 pCi/L No EPA limit set Highest in the city: PALO ALTO PARK MUTUAL WATER COMPANY · 2,900 people · 2016 | 1/2 | SYR4 |
| Dibromochloromethane | 1.36 µg/L No EPA limit set Main supplier: CITY OF EAST PALO ALTO · 29,519 people · 2019
Highest in the city: 1.424 µg/L — PALO ALTO PARK MUTUAL WATER COMPANY · 2,900 people · 2017 | 2/2 | SYR4 |
| Dibromoacetic Acid | 1 µg/L No EPA limit set Main supplier: CITY OF EAST PALO ALTO · 29,519 people · 2019 | 1/2 | SYR4 |
| Lead | 0.0 mg/L 0% of the EPA limit 0.0150 mg/L Main supplier: CITY OF EAST PALO ALTO · 29,519 people · 2023
Highest in the city: 0.0027 mg/L — PALO ALTO PARK MUTUAL WATER COMPANY · 2,900 people · 2023 | 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.
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 East Palo Alto
| Supplier | Population served |
|---|---|
| CITY OF EAST PALO ALTO | 29,519 |
| PALO ALTO PARK MUTUAL WATER COMPANY | 2,900 |
Frequently asked questions about East Palo Alto tap water
Is East Palo Alto tap water safe to drink?
EPA testing detected 23 contaminants in the water serving East Palo Alto. 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 East Palo Alto?
2 public water suppliers report drinking-water monitoring for East Palo Alto, California to the EPA. Each is listed above with its population served.
What contaminants are in East Palo Alto's water?
The contaminants EPA monitoring detected in East Palo Alto include Nitrate, Nitrate-Nitrite, Barium, Fluoride, Cyanide. 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.