Copper Contamination

Copper in New Hampshire Drinking Water

Ranked by 90th percentile copper level (mg/L) · Data from EPA SDWIS & UCMR

Cities Tested

Exceeds Limit

100%

% Exceeds Limit

2.466 mg/L

State Avg

▼ 0% vs national

vs National

118

Health Violations

Analysis

Copper in New Hampshire: what the data shows

New Hampshire has 65 cities with copper monitoring data. The state average 90th percentile copper level is 2.466 mg/L, compared to 28.808 mg/L nationally — better than the national average. 65 cities exceed the EPA action level of 1.3 mg/L. Copper in drinking water typically comes from corrosion of copper pipes and plumbing fixtures, particularly in older homes. The EPA action level of 1.3 mg/L is the 90th percentile threshold — if more than 10% of tap samples exceed it, utilities must take corrective action including adjusting water chemistry to reduce corrosivity. Short-term copper exposure above the action level can cause gastrointestinal distress. Long-term exposure at elevated levels is associated with liver and kidney damage. Flushing your tap for 30 seconds before use and using an NSF 53-certified filter can reduce copper exposure.

Comparison

Cities exceeding 1.3 mg/L EPA Action Level

New Hampshire

100%

65 of 65 cities

← = Exactly at national rate

National avg

100%

3953 of 3953 cities

City Map

Copper data across New Hampshire

Each dot is a city, colored by overall water quality grade. Cities with copper levels above the 1.3 mg/L EPA action level are highlighted. Size reflects population served.

Worst Offenders

Top 10 cities by copper level in New Hampshire

Highest Copper levels (mg/L)

All Cities

All New Hampshire cities ranked by copper level

#	City	Level	Exceeds?	Violations	Grade
1	Tamworth	7.525 mg/L	Yes	64	F
2	Goffstown	5.640 mg/L	Yes	26	D
3	Conway	4.900 mg/L	Yes	95	F
4	Weare	4.400 mg/L	Yes	67	F
5	Bristol	4.100 mg/L	Yes	4	A-
6	Gorham	4.070 mg/L	Yes	3	B-
7	Thornton	3.915 mg/L	Yes	69	F
8	Raymond	3.905 mg/L	Yes	52	F
9	Hopkinton	3.900 mg/L	Yes	54	F
10	Gilford	3.820 mg/L	Yes	122	F
11	Londonderry	3.770 mg/L	Yes	134	F
12	Rollinsford	3.660 mg/L	Yes	19	C+
13	Allenstown	3.320 mg/L	Yes	32	C-
14	Jaffrey	3.310 mg/L	Yes	8	B+
15	Canaan	3.250 mg/L	Yes	50	F
16	Bennington	3.200 mg/L	Yes	23	B
17	Campton	2.880 mg/L	Yes	76	F
18	Wilton	2.750 mg/L	Yes	2	B
19	Freedom	2.720 mg/L	Yes	24	F
20	Charlestown	2.600 mg/L	Yes	23	C-
21	Marlborough	2.520 mg/L	Yes	4	A-
22	Madison	2.510 mg/L	Yes	11	D
23	Brentwood	2.410 mg/L	Yes	3	C+
24	Alton	2.400 mg/L	Yes	31	D
25	Jackson	2.370 mg/L	Yes	21	C-
26	Kingston	2.350 mg/L	Yes	9	D+
27	Plainfield	2.330 mg/L	Yes	4	C+
28	Lisbon	2.280 mg/L	Yes	6	C
29	Hinsdale	2.250 mg/L	Yes	6	B-
30	Rye	2.220 mg/L	Yes	5	A-
31	Ashland	2.180 mg/L	Yes	10	C+
32	Whitefield	2.170 mg/L	Yes	7	B+
33	Ossipee	2.134 mg/L	Yes	27	F
34	Epsom	2.134 mg/L	Yes	27	D
35	Barrington	2.060 mg/L	Yes	117	F
36	Exeter	2.020 mg/L	Yes	60	F
37	Wakefield	2.000 mg/L	Yes	15	D+
38	Belmont	1.990 mg/L	Yes	47	F
39	Warner	1.900 mg/L	Yes	14	C
40	Franklin	1.860 mg/L	Yes	2	A-
41	Haverhill	1.850 mg/L	Yes	18	D
42	Plymouth	1.790 mg/L	Yes	50	C
43	Pittsfield	1.750 mg/L	Yes	10	C+
44	New Hampton	1.750 mg/L	Yes	73	F
45	Berlin	1.710 mg/L	Yes	1	B+
46	Moultonborough	1.700 mg/L	Yes	44	F
47	Bethlehem	1.600 mg/L	Yes	52	D+
48	Swanzey	1.585 mg/L	Yes	22	D+
49	Hampstead	1.570 mg/L	Yes	17	B-
50	Lincoln	1.540 mg/L	Yes	14	B+
51	Greenville	1.537 mg/L	Yes	14	D
52	Derry	1.510 mg/L	Yes	63	F
53	Winchester	1.510 mg/L	Yes	6	C-
54	Keene	1.500 mg/L	Yes	13	A-
55	Seabrook	1.480 mg/L	Yes	29	C+
56	Bartlett	1.470 mg/L	Yes	193	D
57	New Castle	1.450 mg/L	Yes	20	C+
58	New London	1.440 mg/L	Yes	29	C+
59	Portsmouth	1.430 mg/L	Yes	12	B+
60	Boscawen	1.430 mg/L	Yes	10	A-
61	Dover	1.400 mg/L	Yes	10	B+
62	Pembroke	1.400 mg/L	Yes	18	B
63	Stow	1.400 mg/L	Yes	7	C-
64	Troy	1.400 mg/L	Yes	5	B-
65	Hudson	1.360 mg/L	Yes	27	B

FAQ

Frequently asked questions about copper in New Hampshire

Is copper in New Hampshire drinking water safe?

65 cities in New Hampshire exceed the EPA action level of 1.3 mg/L for copper. The state average is 2.466 mg/L. Copper levels are highest in homes with copper plumbing, particularly when water sits in pipes overnight. Flushing the tap before use significantly reduces copper in drinking water.

What causes high copper levels in New Hampshire tap water?

Copper typically leaches from copper pipes and brass fittings within homes, not from the water source itself. Corrosive (low pH or soft) water accelerates this leaching. Water utilities with high copper readings are required to adjust water chemistry to reduce corrosivity. You can reduce exposure by flushing your tap for 30 seconds before use.

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