What was found in Derry'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 | 86000 µg/L 860% of the EPA limit, at the 95th percentile of samples — 10000 µg/L Highest in the city: FARMSTEAD ACRES · 93 people · 2019 | 8/15 | SYR4 |
| Fluoride | 910 µg/L 23% of the EPA limit 4000 µg/L Highest in the city: HI AND LO ESTATES · 150 people · 2018 | 9/15 | SYR4 |
| Copper | 122.807 µg/L 9.4% of the EPA limit 1300 µg/L Main supplier: DERRY WATER DEPT · 17,370 people · 2017
Highest in the city: 558.55 µg/L — GLEN RIDGE DEV · 263 people · 2018 | 15/15 | SYR4 |
| Lead | 24.7968 µg/L 165% of the EPA limit, at the 95th percentile of samples — 15 µg/L Main supplier: DERRY WATER DEPT · 17,370 people · 2017
Highest in the city: 108 µg/L — DREW WOODS · 1,413 people · 2018 | 11/15 | SYR4 |
| Barium | 69.4 µg/L 3.5% of the EPA limit 2000 µg/L Highest in the city: ANNIE OAKLEY MHP · 127 people · 2018 | 11/15 | SYR4 |
| Combined Uranium | 25.52 µg/L 85% of the EPA limit 30 µg/L Highest in the city: GLEN RIDGE DEV · 263 people · 2019 | 7/15 | SYR4 |
| Monochloroacetic Acid | 23 µg/L No EPA limit set Main supplier: DERRY WATER DEPT · 17,370 people · 2019 | 2/15 | SYR4 |
| Nitrite | 20 µg/L 2% of the EPA limit 1000 µg/L Highest in the city: ANNIE OAKLEY MHP · 127 people · 2017 | 1/15 | SYR4 |
| Total Haloacetic Acids (HAA5) | 16.3 µg/L 27% of the EPA limit 60 µg/L Main supplier: DERRY WATER DEPT · 17,370 people · 2019 | 9/15 | SYR4 |
| TTHM | 7.52 µg/L 9.4% of the EPA limit 80 µg/L Main supplier: DERRY WATER DEPT · 17,370 people · 2019
Highest in the city: 14.55 µg/L — FARMSTEAD ACRES · 93 people · 2019 | 13/15 | SYR4 |
| Gross Alpha, Excl. Radon And U | 14.11 pCi/L 94% of the EPA limit 15 pCi/L Highest in the city: FARMSTEAD ACRES · 93 people · 2019 | 10/15 | SYR4 |
| Arsenic | 13.0127 µg/L 130% of the EPA limit, at the 95th percentile of samples — 10 µg/L Highest in the city: OLD COACH VILLAGE · 50 people · 2019 | 8/15 | SYR4 |
| Trichloroacetic Acid | 8.57 µg/L No EPA limit set Main supplier: DERRY WATER DEPT · 17,370 people · 2019 | 2/15 | SYR4 |
| Dichloroacetic Acid | 7.48 µg/L No EPA limit set Main supplier: DERRY WATER DEPT · 17,370 people · 2019 | 4/15 | SYR4 |
| Chromium | 5.95 µg/L 6% of the EPA limit 100 µg/L Highest in the city: ANNIE OAKLEY MHP · 127 people · 2018 | 8/15 | SYR4 |
| Dibromochloromethane | 0.9000 µg/L No EPA limit set Main supplier: DERRY WATER DEPT · 17,370 people · 2019
Highest in the city: 5.35 µg/L — FARMSTEAD ACRES · 93 people · 2019 | 12/15 | SYR4 |
| Chloroform | 4.845 µg/L No EPA limit set Main supplier: DERRY WATER DEPT · 17,370 people · 2019 | 10/15 | SYR4 |
| Dibromoacetic Acid | 4.46 µg/L No EPA limit set Highest in the city: CENTENNIAL ESTATES · 140 people · 2019 | 5/15 | SYR4 |
| Bromodichloromethane | 2.16 µg/L No EPA limit set Main supplier: DERRY WATER DEPT · 17,370 people · 2019
Highest in the city: 4.26 µg/L — FARMSTEAD ACRES · 93 people · 2019 | 10/15 | SYR4 |
| Combined Radium (-226 And -228) | 3.76 pCi/L 75% of the EPA limit 5 pCi/L Highest in the city: GLEN RIDGE DEV · 263 people · 2018 | 8/15 | SYR4 |
| Bromoform | 2.96 µg/L No EPA limit set Highest in the city: CENTENNIAL ESTATES · 140 people · 2019 | 8/15 | SYR4 |
| Diquat | 1.9 µg/L 9.5% of the EPA limit 20 µg/L Highest in the city: AUTUMN WOODS · 73 people · 2019 | 1/15 | SYR4 |
| Toluene | 1.6 µg/L 0.2% of the EPA limit 1000 µg/L Highest in the city: OLD COACH VILLAGE · 50 people · 2019 | 1/15 | SYR4 |
| Di(2-ethylhexyl) Phthalate | 1.2 µg/L 20% of the EPA limit 6 µg/L Highest in the city: DREW WOODS · 1,413 people · 2017 | 1/15 | SYR4 |
| Lead | 0.0 mg/L 0% of the EPA limit 0.0150 mg/L Main supplier: DERRY WATER DEPT · 17,370 people · 2023
Highest in the city: 0.0190 mg/L — RUNNING BROOK · 47 people · 2019 | 2/15 | LCR |
| PFOA | 0.0046 µg/L No EPA limit set Main supplier: DERRY WATER DEPT · 17,370 people · 2024 | 1/15 | UCMR-5 |
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 Derry
| Supplier | Population served |
|---|---|
| DERRY WATER DEPT | 17,370 |
| DREW WOODS | 1,413 |
| MAPLE HILL ACRES | 500 |
| OAKWOOD TERRACE | 310 |
| GLEN RIDGE DEV | 263 |
| MAPLE HAVEN | 258 |
| RAND SHEPARD HILL | 158 |
| HI AND LO ESTATES | 150 |
| CENTENNIAL ESTATES | 140 |
| ANNIE OAKLEY MHP | 127 |
| FARMSTEAD ACRES | 93 |
| AUTUMN WOODS | 73 |
| WILLOW BEND | 55 |
| OLD COACH VILLAGE | 50 |
| RUNNING BROOK | 47 |
Frequently asked questions about Derry tap water
Is Derry tap water safe to drink?
EPA testing detected 26 contaminants in the water serving Derry. 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 Derry?
15 public water suppliers report drinking-water monitoring for Derry, New Hampshire to the EPA. Each is listed above with its population served.
What contaminants are in Derry's water?
The contaminants EPA monitoring detected in Derry include Nitrate, Fluoride, Copper, Lead, 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.