Is Thornton, NH Tap Water Safe? Quality & Contaminants

What was found in Thornton'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	300 µg/L 3% of the EPA limit 10000 µg/L Main supplier: OWLS NEST GOLF CLUB AND CONDOS · 272 people · 2019 Highest in the city: 11300 µg/L — NORTHPOINTE WATER · 48 people · 2019	5/10	SYR4
Fluoride	841.95 µg/L 21% of the EPA limit 4000 µg/L Main supplier: OWLS NEST GOLF CLUB AND CONDOS · 272 people · 2017 Highest in the city: 3090 µg/L — STAR RIDGE · 96 people · 2019	9/10	SYR4
Lead	668.857 µg/L 4459% of the EPA limit, at the 95th percentile of samples — 15 µg/L Main supplier: OWLS NEST GOLF CLUB AND CONDOS · 272 people · 2018	9/10	SYR4
Copper	129.6 µg/L 10% of the EPA limit 1300 µg/L Main supplier: OWLS NEST GOLF CLUB AND CONDOS · 272 people · 2018 Highest in the city: 407.87 µg/L — MILL BROOK VILLAGE · 113 people · 2017	10/10	SYR4
Nitrate-Nitrite	245 µg/L 2.5% of the EPA limit 10000 µg/L Highest in the city: MILL BROOK VILLAGE · 113 people · 2018	1/10	SYR4
Barium	27.8691 µg/L 1.4% of the EPA limit 2000 µg/L Main supplier: OWLS NEST GOLF CLUB AND CONDOS · 272 people · 2017 Highest in the city: 47.8 µg/L — MOUNTAIN RIVER CONDOS EAST · 200 people · 2017	8/10	SYR4
Combined Uranium	3.775 µg/L 13% of the EPA limit 30 µg/L Main supplier: OWLS NEST GOLF CLUB AND CONDOS · 272 people · 2018 Highest in the city: 47.4 µg/L — 175 ESTATES · 100 people · 2019	8/10	SYR4
Gross Alpha, Excl. Radon And U	2.3 pCi/L 15% of the EPA limit 15 pCi/L Main supplier: OWLS NEST GOLF CLUB AND CONDOS · 272 people · 2015 Highest in the city: 18.18 pCi/L — 175 ESTATES · 100 people · 2019	9/10	SYR4
Chloroform	12 µg/L No EPA limit set Highest in the city: 175 ESTATES · 100 people · 2019	1/10	SYR4
Combined Radium (-226 And -228)	0.8000 pCi/L 16% of the EPA limit 5 pCi/L Main supplier: OWLS NEST GOLF CLUB AND CONDOS · 272 people · 2015 Highest in the city: 2.4 pCi/L — MOUNTAIN RIVER CONDOS · 60 people · 2014	7/10	SYR4
Bromodichloromethane	2.3 µg/L No EPA limit set Highest in the city: 175 ESTATES · 100 people · 2019	1/10	SYR4
Chromium	1.827 µg/L 1.8% of the EPA limit 100 µg/L Main supplier: OWLS NEST GOLF CLUB AND CONDOS · 272 people · 2017 Highest in the city: 2 µg/L — NORTHPOINTE WATER · 48 people · 2018	2/10	SYR4
Di(2-ethylhexyl) Phthalate	1.2 µg/L 20% of the EPA limit 6 µg/L Highest in the city: STAR RIDGE · 96 people · 2019	1/10	SYR4
Arsenic	1 µg/L 10% of the EPA limit 10 µg/L Highest in the city: MOUNTAIN RIVER CONDOS EAST · 200 people · 2017	1/10	SYR4
Tetrachloroethylene	0.8900 µg/L 18% of the EPA limit 5 µg/L Highest in the city: MILL BROOK VILLAGE · 113 people · 2018	1/10	SYR4
Toluene	0.7700 µg/L 0.1% of the EPA limit 1000 µg/L Highest in the city: 175 ESTATES · 100 people · 2019	1/10	SYR4
Lead	0.5660 mg/L 3773% above the EPA limit of 0.0150 mg/L Main supplier: OWLS NEST GOLF CLUB AND CONDOS · 272 people · 2017	4/10	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 Thornton

Supplier	Population served
OWLS NEST GOLF CLUB AND CONDOS	272
WHITE MOUNTAIN RESORT/GATEWAY	213
MOUNTAIN RIVER CONDOS EAST	200
MILL BROOK VILLAGE	113
175 ESTATES	100
STAR RIDGE	96
MOUNTAIN RIVER CONDOS	60
WATERVILLE ACRES CONDOS	50
NORTHPOINTE WATER	48
BIRCH BEND	28

Frequently asked questions about Thornton tap water

Is Thornton tap water safe to drink?

EPA testing detected 17 contaminants in the water serving Thornton. 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 Thornton?

10 public water suppliers report drinking-water monitoring for Thornton, New Hampshire to the EPA. Each is listed above with its population served.

What contaminants are in Thornton's water?

The contaminants EPA monitoring detected in Thornton include Nitrate, Fluoride, Lead, Copper, Nitrate-Nitrite. 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.