What was found in Jamestown'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 | 144015 µg/L 1440% of the EPA limit, at the 95th percentile of samples — 10000 µg/L Main supplier: CDCR - SIERRA CONSERVATION CENTER · 3,571 people · 2017 | 1/4 | SYR4 |
| Nitrate | 150 µg/L 1.5% of the EPA limit 10000 µg/L Main supplier: CDCR - SIERRA CONSERVATION CENTER · 3,571 people · 2019
Highest in the city: 3553.66 µg/L — RAWHIDE MUTUAL WATER COMPANY · 269 people · 2019 | 2/4 | SYR4 |
| Fluoride | 193.1 µg/L 4.8% of the EPA limit 4000 µg/L Highest in the city: SIERRA TWAIN HARTE MHP · 129 people · 2019 | 1/4 | SYR4 |
| Barium | 14.86 µg/L 0.7% of the EPA limit 2000 µg/L Main supplier: CDCR - SIERRA CONSERVATION CENTER · 3,571 people · 2019
Highest in the city: 95.21 µg/L — RAWHIDE MUTUAL WATER COMPANY · 269 people · 2018 | 2/4 | SYR4 |
| TTHM | 80.085 µg/L 100% of the EPA limit, at the 95th percentile of samples — 80 µg/L Main supplier: CDCR - SIERRA CONSERVATION CENTER · 3,571 people · 2019
Highest in the city: 85.2 µg/L — CAL FIRE BASELINE CONSERVATION CAMP · 150 people · 2018 | 4/4 | SYR4 |
| Chloroform | 77.135 µg/L No EPA limit set Main supplier: CDCR - SIERRA CONSERVATION CENTER · 3,571 people · 2019
Highest in the city: 83.2 µg/L — CAL FIRE BASELINE CONSERVATION CAMP · 150 people · 2018 | 4/4 | SYR4 |
| Total Haloacetic Acids (HAA5) | 73.515 µg/L 123% of the EPA limit, at the 95th percentile of samples — 60 µg/L Main supplier: CDCR - SIERRA CONSERVATION CENTER · 3,571 people · 2019 | 4/4 | SYR4 |
| Trichloroacetic Acid | 45.55 µg/L No EPA limit set Main supplier: CDCR - SIERRA CONSERVATION CENTER · 3,571 people · 2019 | 3/4 | SYR4 |
| Dichloroacetic Acid | 27.66 µg/L No EPA limit set Main supplier: CDCR - SIERRA CONSERVATION CENTER · 3,571 people · 2019 | 4/4 | SYR4 |
| Chromium | 11.4 µg/L 11% of the EPA limit 100 µg/L Highest in the city: RAWHIDE MUTUAL WATER COMPANY · 269 people · 2018 | 1/4 | SYR4 |
| Dichloromethane | 8.39 µg/L 168% of the EPA limit, at the 95th percentile of samples — 5 µg/L Highest in the city: SIERRA TWAIN HARTE MHP · 129 people · 2018 | 1/4 | SYR4 |
| Copper | 6.7 µg/L 0.5% of the EPA limit 1300 µg/L Main supplier: CDCR - SIERRA CONSERVATION CENTER · 3,571 people · 2019 | 1/4 | SYR4 |
| Monobromoacetic Acid | 5.6 µg/L No EPA limit set Highest in the city: RAWHIDE MUTUAL WATER COMPANY · 269 people · 2017 | 2/4 | SYR4 |
| Bromodichloromethane | 4.745 µg/L No EPA limit set Main supplier: CDCR - SIERRA CONSERVATION CENTER · 3,571 people · 2019 | 3/4 | SYR4 |
| Dibromoacetic Acid | 3.105 µg/L No EPA limit set Main supplier: CDCR - SIERRA CONSERVATION CENTER · 3,571 people · 2019
Highest in the city: 3.93 µg/L — RAWHIDE MUTUAL WATER COMPANY · 269 people · 2017 | 3/4 | SYR4 |
| Arsenic | 3.79 µg/L 38% of the EPA limit 10 µg/L Highest in the city: SIERRA TWAIN HARTE MHP · 129 people · 2019 | 2/4 | SYR4 |
| Monochloroacetic Acid | 2.664 µg/L No EPA limit set Main supplier: CDCR - SIERRA CONSERVATION CENTER · 3,571 people · 2019 | 1/4 | SYR4 |
| Dibromochloromethane | 1.514 µg/L No EPA limit set Highest in the city: RAWHIDE MUTUAL WATER COMPANY · 269 people · 2017 | 1/4 | SYR4 |
| Lead | 0.0 mg/L 0% of the EPA limit 0.0150 mg/L Main supplier: CDCR - SIERRA CONSERVATION CENTER · 3,571 people · 2024 | 4/4 | 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 Jamestown
| Supplier | Population served |
|---|---|
| CDCR - SIERRA CONSERVATION CENTER | 3,571 |
| RAWHIDE MUTUAL WATER COMPANY | 269 |
| CAL FIRE BASELINE CONSERVATION CAMP | 150 |
| SIERRA TWAIN HARTE MHP | 129 |
Frequently asked questions about Jamestown tap water
Is Jamestown tap water safe to drink?
EPA testing detected 19 contaminants in the water serving Jamestown. 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 Jamestown?
4 public water suppliers report drinking-water monitoring for Jamestown, California to the EPA. Each is listed above with its population served.
What contaminants are in Jamestown's water?
The contaminants EPA monitoring detected in Jamestown include Nitrate-Nitrite, Nitrate, 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.