What was found in Londonderry'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 | 6609.57 µg/L 66% of the EPA limit 10000 µg/L Highest in the city: OLDE COUNTRY VILLAGE · 130 people · 2019 | 8/17 | SYR4 |
| Copper | 108 µg/L 8.3% of the EPA limit 1300 µg/L Main supplier: LONDONDERRY · 6,255 people · 2018
Highest in the city: 1563 µg/L — PONDEROSA MHP · 110 people · 2018 | 16/17 | SYR4 |
| Fluoride | 1283 µg/L 32% of the EPA limit 4000 µg/L Highest in the city: BOUMIL GROVE CONDOS · 72 people · 2018 | 5/17 | SYR4 |
| Lead | 2.19 µg/L 15% of the EPA limit 15 µg/L Main supplier: LONDONDERRY · 6,255 people · 2018
Highest in the city: 161.975 µg/L — ROLLING MEADOWS CONDOS III · 50 people · 2019 | 14/17 | SYR4 |
| Gross Alpha, Excl. Radon And U | 55.24 pCi/L 368% of the EPA limit, at the 95th percentile of samples — 15 pCi/L Highest in the city: BOUMIL GROVE CONDOS · 72 people · 2019 | 9/17 | SYR4 |
| Barium | 44.906 µg/L 2.2% of the EPA limit 2000 µg/L Highest in the city: PONDEROSA MHP · 110 people · 2017 | 11/17 | SYR4 |
| Combined Uranium | 28.261 µg/L 94% of the EPA limit 30 µg/L Highest in the city: OLDE COUNTRY VILLAGE · 130 people · 2019 | 9/17 | SYR4 |
| TTHM | 6.7 µg/L 8.4% of the EPA limit 80 µg/L Main supplier: LONDONDERRY · 6,255 people · 2019
Highest in the city: 20.25 µg/L — AVERY ESTATES · 383 people · 2019 | 8/17 | SYR4 |
| Total Haloacetic Acids (HAA5) | 14.7 µg/L 25% of the EPA limit 60 µg/L Main supplier: LONDONDERRY · 6,255 people · 2019 | 6/17 | SYR4 |
| Monochloroacetic Acid | 13.92 µg/L No EPA limit set Main supplier: LONDONDERRY · 6,255 people · 2019 | 3/17 | SYR4 |
| Arsenic | 12.42 µg/L 124% of the EPA limit, at the 95th percentile of samples — 10 µg/L Highest in the city: BITIM APARTMENTS · 28 people · 2019 | 10/17 | SYR4 |
| Chloroform | 4.2 µg/L No EPA limit set Main supplier: LONDONDERRY · 6,255 people · 2019
Highest in the city: 11.01 µg/L — AVERY ESTATES · 383 people · 2019 | 8/17 | SYR4 |
| Dichloroacetic Acid | 8.44 µg/L No EPA limit set Main supplier: LONDONDERRY · 6,255 people · 2019
Highest in the city: 10 µg/L — BROOK PARK ESTS · 880 people · 2019 | 5/17 | SYR4 |
| Trichloroacetic Acid | 7.965 µg/L No EPA limit set Main supplier: LONDONDERRY · 6,255 people · 2019 | 4/17 | SYR4 |
| Combined Radium (-226 And -228) | 7.72 pCi/L 154% of the EPA limit, at the 95th percentile of samples — 5 pCi/L Highest in the city: OAKRIDGE CONDOS · 250 people · 2019 | 9/17 | SYR4 |
| Bromodichloromethane | 1.7 µg/L No EPA limit set Main supplier: LONDONDERRY · 6,255 people · 2019
Highest in the city: 5.925 µg/L — AVERY ESTATES · 383 people · 2019 | 8/17 | SYR4 |
| Dibromochloromethane | 0.9850 µg/L No EPA limit set Main supplier: LONDONDERRY · 6,255 people · 2019
Highest in the city: 5.265 µg/L — AVERY ESTATES · 383 people · 2019 | 8/17 | SYR4 |
| Toluene | 4.7 µg/L 0.5% of the EPA limit 1000 µg/L Highest in the city: SOUTHVIEW CONDOS · 38 people · 2019 | 2/17 | SYR4 |
| Chromium | 4 µg/L 4% of the EPA limit 100 µg/L Highest in the city: BOUMIL GROVE CONDOS · 72 people · 2018 | 9/17 | SYR4 |
| Dibromoacetic Acid | 1.4 µg/L No EPA limit set Main supplier: LONDONDERRY · 6,255 people · 2019
Highest in the city: 1.88 µg/L — MINISTERIAL/PARRISH HILLS · 305 people · 2019 | 4/17 | SYR4 |
| Bromoform | 1.665 µg/L No EPA limit set Highest in the city: PINEHAVEN WATER TRUST · 95 people · 2019 | 5/17 | SYR4 |
| Lead | 0.0 mg/L 0% of the EPA limit 0.0150 mg/L Main supplier: LONDONDERRY · 6,255 people · 2024
Highest in the city: 0.2250 mg/L — ROLLING MEADOWS CONDOS III · 50 people · 2018 | 7/17 | LCR |
| Mercury | 0.1600 µg/L 8% of the EPA limit 2 µg/L Highest in the city: BOUMIL GROVE CONDOS · 72 people · 2018 | 1/17 | SYR4 |
| PFOA | 0.0064 µg/L No EPA limit set Main supplier: LONDONDERRY · 6,255 people · 2024 | 1/17 | 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 Londonderry
| Supplier | Population served |
|---|---|
| LONDONDERRY | 6,255 |
| BROOK PARK ESTS | 880 |
| AVERY ESTATES | 383 |
| MINISTERIAL/PARRISH HILLS | 305 |
| OAKRIDGE CONDOS | 250 |
| SPRINGWOOD HILLS | 228 |
| HARVEST VILLAGE | 185 |
| OLDE COUNTRY VILLAGE | 130 |
| PONDEROSA MHP | 110 |
| HANAFIN FARM | 105 |
| PINEHAVEN WATER TRUST | 95 |
| ROLLING MEADOWS CONDOS I | 88 |
| BOUMIL GROVE CONDOS | 72 |
| ROLLING MEADOWS CONDOS III | 50 |
| ROLLING MEADOWS CONDOS IV | 42 |
| SOUTHVIEW CONDOS | 38 |
| BITIM APARTMENTS | 28 |
Frequently asked questions about Londonderry tap water
Is Londonderry tap water safe to drink?
EPA testing detected 24 contaminants in the water serving Londonderry. 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 Londonderry?
17 public water suppliers report drinking-water monitoring for Londonderry, New Hampshire to the EPA. Each is listed above with its population served.
What contaminants are in Londonderry's water?
The contaminants EPA monitoring detected in Londonderry include Nitrate, Copper, Fluoride, Lead, Gross Alpha, Excl. Radon And U. 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.