What was found in Durham'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 | 1100 µg/L 11% of the EPA limit 10000 µg/L Main supplier: UNH/DURHAM WATER SYS · 16,000 people · 2019
Highest in the city: 4300 µg/L — STAGECOACH FARMS · 167 people · 2019 | 2/4 | SYR4 |
| Fluoride | 639.5 µg/L 16% of the EPA limit 4000 µg/L Main supplier: UNH/DURHAM WATER SYS · 16,000 people · 2019 | 3/4 | SYR4 |
| Copper | 552.3 µg/L 42% of the EPA limit 1300 µg/L Main supplier: UNH/DURHAM WATER SYS · 16,000 people · 2019 | 4/4 | SYR4 |
| Lead | 98.6 µg/L 657% of the EPA limit, at the 95th percentile of samples — 15 µg/L Main supplier: UNH/DURHAM WATER SYS · 16,000 people · 2019 | 3/4 | SYR4 |
| TTHM | 72.95 µg/L 91% of the EPA limit 80 µg/L Main supplier: UNH/DURHAM WATER SYS · 16,000 people · 2019 | 3/4 | SYR4 |
| Chloroform | 56.75 µg/L No EPA limit set Main supplier: UNH/DURHAM WATER SYS · 16,000 people · 2019 | 2/4 | SYR4 |
| Total Haloacetic Acids (HAA5) | 40.75 µg/L 68% of the EPA limit 60 µg/L Main supplier: UNH/DURHAM WATER SYS · 16,000 people · 2019 | 1/4 | SYR4 |
| Trichloroacetic Acid | 26 µg/L No EPA limit set Main supplier: UNH/DURHAM WATER SYS · 16,000 people · 2019 | 1/4 | SYR4 |
| Arsenic | 1.7 µg/L 17% of the EPA limit 10 µg/L Main supplier: UNH/DURHAM WATER SYS · 16,000 people · 2019
Highest in the city: 14 µg/L — JOHNSON CREEK · 63 people · 2019 | 4/4 | SYR4 |
| Dichloroacetic Acid | 13.9 µg/L No EPA limit set Main supplier: UNH/DURHAM WATER SYS · 16,000 people · 2019 | 1/4 | SYR4 |
| Bromodichloromethane | 13 µg/L No EPA limit set Main supplier: UNH/DURHAM WATER SYS · 16,000 people · 2019 | 2/4 | SYR4 |
| Barium | 12.55 µg/L 0.6% of the EPA limit 2000 µg/L Main supplier: UNH/DURHAM WATER SYS · 16,000 people · 2019
Highest in the city: 12.9 µg/L — JOHNSON CREEK · 63 people · 2019 | 4/4 | SYR4 |
| Gross Alpha, Excl. Radon And U | 2.1 pCi/L 14% of the EPA limit 15 pCi/L Main supplier: UNH/DURHAM WATER SYS · 16,000 people · 2017
Highest in the city: 3 pCi/L — BROOKDALE SPRUCE WOOD · 225 people · 2019 | 3/4 | SYR4 |
| Combined Uranium | 0.9800 µg/L 3.3% of the EPA limit 30 µg/L Main supplier: UNH/DURHAM WATER SYS · 16,000 people · 2017
Highest in the city: 2.845 µg/L — STAGECOACH FARMS · 167 people · 2014 | 2/4 | SYR4 |
| Dibromochloromethane | 2.75 µg/L No EPA limit set Main supplier: UNH/DURHAM WATER SYS · 16,000 people · 2019 | 2/4 | SYR4 |
| Monobromoacetic Acid | 1.685 µg/L No EPA limit set Main supplier: UNH/DURHAM WATER SYS · 16,000 people · 2019 | 1/4 | SYR4 |
| Combined Radium (-226 And -228) | 1.45 pCi/L 29% of the EPA limit 5 pCi/L Main supplier: UNH/DURHAM WATER SYS · 16,000 people · 2017
Highest in the city: 1.6 pCi/L — BROOKDALE SPRUCE WOOD · 225 people · 2019 | 4/4 | SYR4 |
| Chromium | 1.1 µg/L 1.1% of the EPA limit 100 µg/L Highest in the city: BROOKDALE SPRUCE WOOD · 225 people · 2019 | 1/4 | SYR4 |
| Bromoform | 1 µg/L No EPA limit set Highest in the city: JOHNSON CREEK · 63 people · 2019 | 2/4 | SYR4 |
| Lead | 0.0 mg/L 0% of the EPA limit 0.0150 mg/L Main supplier: UNH/DURHAM WATER SYS · 16,000 people · 2024
Highest in the city: 0.2660 mg/L — BROOKDALE SPRUCE WOOD · 225 people · 2013 | 2/4 | LCR |
| Mercury | 0.2000 µg/L 10% of the EPA limit 2 µg/L Highest in the city: STAGECOACH FARMS · 167 people · 2018 | 2/4 | 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 Durham
| Supplier | Population served |
|---|---|
| UNH/DURHAM WATER SYS | 16,000 |
| BROOKDALE SPRUCE WOOD | 225 |
| STAGECOACH FARMS | 167 |
| JOHNSON CREEK | 63 |
Frequently asked questions about Durham tap water
Is Durham tap water safe to drink?
EPA testing detected 21 contaminants in the water serving Durham. 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 Durham?
4 public water suppliers report drinking-water monitoring for Durham, New Hampshire to the EPA. Each is listed above with its population served.
What contaminants are in Durham's water?
The contaminants EPA monitoring detected in Durham include Nitrate, Fluoride, Copper, Lead, 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.