What was found in Redwood City'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 | 7524.1 µg/L 75% of the EPA limit 10000 µg/L Highest in the city: COUNTY SERVICE AREA 11 · 642 people · 2019 | 2/3 | SYR4 |
| Nitrate-Nitrite | 4585 µg/L 46% of the EPA limit 10000 µg/L Highest in the city: COUNTY SERVICE AREA 11 · 642 people · 2018 | 1/3 | SYR4 |
| Fluoride | 444 µg/L 11% of the EPA limit 4000 µg/L Highest in the city: COUNTY SERVICE AREA 7 · 300 people · 2019 | 2/3 | SYR4 |
| Barium | 140 µg/L 7% of the EPA limit 2000 µg/L Highest in the city: COUNTY SERVICE AREA 11 · 642 people · 2018 | 1/3 | SYR4 |
| TTHM | 61.946 µg/L 77% of the EPA limit 80 µg/L Main supplier: CITY OF REDWOOD CITY · 92,819 people · 2019
Highest in the city: 123.758 µg/L — COUNTY SERVICE AREA 7 · 300 people · 2019 | 2/3 | SYR4 |
| Total Haloacetic Acids (HAA5) | 53.43 µg/L 89% of the EPA limit 60 µg/L Main supplier: CITY OF REDWOOD CITY · 92,819 people · 2019
Highest in the city: 75.72 µg/L — COUNTY SERVICE AREA 7 · 300 people · 2019 | 2/3 | SYR4 |
| Chloroform | 61.3085 µg/L No EPA limit set Main supplier: CITY OF REDWOOD CITY · 92,819 people · 2019
Highest in the city: 69.015 µg/L — COUNTY SERVICE AREA 7 · 300 people · 2019 | 2/3 | SYR4 |
| Trichloroacetic Acid | 24.175 µg/L No EPA limit set Main supplier: CITY OF REDWOOD CITY · 92,819 people · 2019
Highest in the city: 41.4 µg/L — COUNTY SERVICE AREA 7 · 300 people · 2019 | 2/3 | SYR4 |
| Bromodichloromethane | 3.966 µg/L No EPA limit set Main supplier: CITY OF REDWOOD CITY · 92,819 people · 2019
Highest in the city: 39.39 µg/L — COUNTY SERVICE AREA 7 · 300 people · 2019 | 2/3 | SYR4 |
| Dibromochloromethane | 1.25 µg/L No EPA limit set Main supplier: CITY OF REDWOOD CITY · 92,819 people · 2019
Highest in the city: 30.5975 µg/L — COUNTY SERVICE AREA 7 · 300 people · 2019 | 2/3 | SYR4 |
| Dichloroacetic Acid | 30.165 µg/L No EPA limit set Main supplier: CITY OF REDWOOD CITY · 92,819 people · 2019 | 2/3 | SYR4 |
| Chromium | 26.3 µg/L 26% of the EPA limit 100 µg/L Highest in the city: COUNTY SERVICE AREA 11 · 642 people · 2018 | 1/3 | SYR4 |
| Arsenic | 12.515 µg/L 125% of the EPA limit, at the 95th percentile of samples — 10 µg/L Highest in the city: COUNTY SERVICE AREA 11 · 642 people · 2018 | 2/3 | SYR4 |
| Lead | 9.7 µg/L 65% of the EPA limit 15 µg/L Highest in the city: COUNTY SERVICE AREA 11 · 642 people · 2018 | 1/3 | SYR4 |
| Antimony, Total | 7.2 µg/L 120% of the EPA limit, at the 95th percentile of samples — 6 µg/L Highest in the city: COUNTY SERVICE AREA 11 · 642 people · 2018 | 1/3 | SYR4 |
| Bromoform | 1.4 µg/L No EPA limit set Main supplier: CITY OF REDWOOD CITY · 92,819 people · 2019
Highest in the city: 6.7025 µg/L — COUNTY SERVICE AREA 7 · 300 people · 2019 | 2/3 | SYR4 |
| Dibromoacetic Acid | 1.7 µg/L No EPA limit set Main supplier: CITY OF REDWOOD CITY · 92,819 people · 2019
Highest in the city: 5.96 µg/L — COUNTY SERVICE AREA 7 · 300 people · 2019 | 2/3 | SYR4 |
| Monochloroacetic Acid | 3.67 µg/L No EPA limit set Main supplier: CITY OF REDWOOD CITY · 92,819 people · 2019 | 1/3 | SYR4 |
| Cadmium | 1 µg/L 20% of the EPA limit 5 µg/L Highest in the city: COUNTY SERVICE AREA 11 · 642 people · 2018 | 1/3 | SYR4 |
| Lead | 0.0 mg/L 0% of the EPA limit 0.0150 mg/L Main supplier: CITY OF REDWOOD CITY · 92,819 people · 2024
Highest in the city: 0.0018 mg/L — COUNTY SERVICE AREA 7 · 300 people · 2028 | 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.
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 Redwood City
| Supplier | Population served |
|---|---|
| CITY OF REDWOOD CITY | 92,819 |
| COUNTY SERVICE AREA 11 | 642 |
| COUNTY SERVICE AREA 7 | 300 |
Frequently asked questions about Redwood City tap water
Is Redwood City tap water safe to drink?
EPA testing detected 20 contaminants in the water serving Redwood City. 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 Redwood City?
3 public water suppliers report drinking-water monitoring for Redwood City, California to the EPA. Each is listed above with its population served.
What contaminants are in Redwood City's water?
The contaminants EPA monitoring detected in Redwood City include Nitrate, Nitrate-Nitrite, Fluoride, Barium, TTHM. 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.