Is Nashua, NH Tap Water Safe? Quality & Contaminants

What was found in Nashua'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	680 µg/L 6.8% of the EPA limit 10000 µg/L Main supplier: PENNICHUCK WATER WORKS · 88,853 people · 2019	1/2	SYR4
Fluoride	411.55 µg/L 10% of the EPA limit 4000 µg/L Highest in the city: FARLEY RD ESTATES · 85 people · 2019	1/2	SYR4
Barium	12.2273 µg/L 0.6% of the EPA limit 2000 µg/L Main supplier: PENNICHUCK WATER WORKS · 88,853 people · 2019 Highest in the city: 118 µg/L — FARLEY RD ESTATES · 85 people · 2019	2/2	SYR4
Copper	96.06 µg/L 7.4% of the EPA limit 1300 µg/L Main supplier: PENNICHUCK WATER WORKS · 88,853 people · 2019	2/2	SYR4
TTHM	61.75 µg/L 77% of the EPA limit 80 µg/L Main supplier: PENNICHUCK WATER WORKS · 88,853 people · 2019	2/2	SYR4
Lead	59.538 µg/L 397% of the EPA limit, at the 95th percentile of samples — 15 µg/L Main supplier: PENNICHUCK WATER WORKS · 88,853 people · 2017	1/2	SYR4
Chloroform	41 µg/L No EPA limit set Main supplier: PENNICHUCK WATER WORKS · 88,853 people · 2019	2/2	SYR4
Total Haloacetic Acids (HAA5)	21.8 µg/L 36% of the EPA limit 60 µg/L Main supplier: PENNICHUCK WATER WORKS · 88,853 people · 2019	1/2	SYR4
Arsenic	18.804 µg/L 188% of the EPA limit, at the 95th percentile of samples — 10 µg/L Highest in the city: FARLEY RD ESTATES · 85 people · 2019	1/2	SYR4
Bromodichloromethane	15 µg/L No EPA limit set Main supplier: PENNICHUCK WATER WORKS · 88,853 people · 2019	2/2	SYR4
Dichloroacetic Acid	12 µg/L No EPA limit set Main supplier: PENNICHUCK WATER WORKS · 88,853 people · 2019	1/2	SYR4
Lithium	11.3 µg/L No EPA limit set Highest in the city: FARLEY RD ESTATES · 85 people · 2024	1/2	UCMR-5
Trichloroacetic Acid	9.9844 µg/L No EPA limit set Main supplier: PENNICHUCK WATER WORKS · 88,853 people · 2019	1/2	SYR4
Dibromochloromethane	5.27 µg/L No EPA limit set Main supplier: PENNICHUCK WATER WORKS · 88,853 people · 2019	2/2	SYR4
Di(2-ethylhexyl) Phthalate	2.595 µg/L 43% of the EPA limit 6 µg/L Highest in the city: FARLEY RD ESTATES · 85 people · 2018	1/2	SYR4
Dibromoacetic Acid	1.96113 µg/L No EPA limit set Main supplier: PENNICHUCK WATER WORKS · 88,853 people · 2019	1/2	SYR4
Bromoform	0.9450 µg/L No EPA limit set Main supplier: PENNICHUCK WATER WORKS · 88,853 people · 2019	2/2	SYR4
Toluene	0.7900 µg/L 0.1% of the EPA limit 1000 µg/L Highest in the city: FARLEY RD ESTATES · 85 people · 2018	1/2	SYR4
Gross Alpha, Excl. Radon And U	0.6750 pCi/L 4.5% of the EPA limit 15 pCi/L Highest in the city: FARLEY RD ESTATES · 85 people · 2014	1/2	SYR4
Combined Radium (-226 And -228)	0.5000 pCi/L 10% of the EPA limit 5 pCi/L Main supplier: PENNICHUCK WATER WORKS · 88,853 people · 2016	2/2	SYR4
Lead	0.0 mg/L 0% of the EPA limit 0.0150 mg/L Main supplier: PENNICHUCK WATER WORKS · 88,853 people · 2023	1/2	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 Nashua

Supplier	Population served
PENNICHUCK WATER WORKS	88,853
FARLEY RD ESTATES	85

Frequently asked questions about Nashua tap water

Is Nashua tap water safe to drink?

EPA testing detected 21 contaminants in the water serving Nashua. 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 Nashua?

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

What contaminants are in Nashua's water?

The contaminants EPA monitoring detected in Nashua include Nitrate, Fluoride, Barium, Copper, 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.