Nitrate Contamination

Nitrate in Maine Drinking Water

Ranked by nitrate violation count · Data from EPA SDWIS & UCMR

Cities Tested

Has Violations

100%

% Has Violations

3.9 violations

State Avg

▼ 0% vs national

vs National

141

Health Violations

Analysis

Nitrate in Maine: what the data shows

Maine has 85 cities with nitrate-related violations. The EPA MCL for nitrate is 10 mg/L (measured as nitrogen). The state has 85 cities with at least one nitrate violation. Nitrate is the most common groundwater contaminant in the United States. It enters water supplies primarily through agricultural fertilizer runoff, septic system leaching, and animal feedlot operations. Rural and agricultural communities face the highest risk. The primary acute health concern is methemoglobinemia ("blue baby syndrome") in infants under six months. Emerging research also links chronic nitrate exposure to thyroid disease, certain cancers, and adverse birth outcomes. Reverse osmosis, ion exchange, and distillation can remove nitrate from drinking water — standard carbon filters do not.

Comparison

Cities exceeding 10 mg/L EPA MCL

Maine

100%

85 of 85 cities

← = Exactly at national rate

National avg

100%

8001 of 8001 cities

City Map

Nitrate data across Maine

Each dot is a city with nitrate violation data. Cities with at least one nitrate-related violation are highlighted. Size reflects population served.

Worst Offenders

Top 10 cities by nitrate level in Maine

Highest Nitrate levels (violations)

All Cities

All Maine cities ranked by nitrate level

#	City	Level	Violations?	Violations	Grade
1	Scarborough	33 violations	Yes	5	B-
2	Clifton	24 violations	Yes	26	F
3	Bridgton	16 violations	Yes	5	D
4	Caribou	16 violations	Yes	26	C
5	Topsham	10 violations	Yes	17	C+
6	Limestone	10 violations	Yes	95	D
7	Princeton	10 violations	Yes	34	D
8	Waterboro	9 violations	Yes	10	B
9	Kennebunkport	8 violations	Yes	12	D+
10	Scarborough	7 violations	Yes	0	B
11	Bangor	7 violations	Yes	3	B
12	Waterville	6 violations	Yes	8	C
13	Waterville	6 violations	Yes	8	F
14	Camden	6 violations	Yes	11	B
15	Orono	6 violations	Yes	12	B-
16	Scarborough	5 violations	Yes	26	C
17	Augusta	5 violations	Yes	8	B+
18	Clifton	5 violations	Yes	5	A-
19	Damariscotta	5 violations	Yes	33	B-
20	Princeton	5 violations	Yes	4	B
21	Hancock	5 violations	Yes	30	D
22	Bangor	4 violations	Yes	7	B
23	Bath	4 violations	Yes	19	B-
24	Gardiner	4 violations	Yes	3	B-
25	Houlton	4 violations	Yes	5	C
26	Bucksport	4 violations	Yes	8	C-
27	Carrabassett Vl	4 violations	Yes	14	C+
28	Strong	4 violations	Yes	0	A-
29	Scarborough	3 violations	Yes	7	B
30	Bangor	3 violations	Yes	5	C+
31	Bath	3 violations	Yes	9	A-
32	Skowhegan	3 violations	Yes	4	B-
33	Presque Isle	3 violations	Yes	24	C+
34	Sabattus	3 violations	Yes	7	A
35	Mars Hill	3 violations	Yes	58	D+
36	Parsonsfield	3 violations	Yes	0	A
37	Parsonsfield	3 violations	Yes	0	A
38	Parsonsfield	3 violations	Yes	0	A
39	Washburn	3 violations	Yes	2	B+
40	Waterville	2 violations	Yes	6	B-
41	Camden	2 violations	Yes	4	C
42	Augusta	2 violations	Yes	15	B+
43	Bath	2 violations	Yes	14	A-
44	Northport	2 violations	Yes	4	B+
45	Northport	2 violations	Yes	9	B-
46	Farmington	2 violations	Yes	1	B
47	Freeport	2 violations	Yes	13	A-
48	Madawaska	2 violations	Yes	7	A
49	Milo	2 violations	Yes	59	B
50	Bingham	2 violations	Yes	8	B-
51	Greenville	2 violations	Yes	2	A
52	Alfred	2 violations	Yes	6	B-
53	Milton	2 violations	Yes	3	B+
54	Bingham	2 violations	Yes	5	B+
55	Castine	2 violations	Yes	10	C+
56	Limerick	2 violations	Yes	9	B
57	North Haven	2 violations	Yes	58	B
58	St George	2 violations	Yes	1	B+
59	Charleston	2 violations	Yes	4	B
60	Bangor	1 violations	Yes	5	B+
61	Bangor	1 violations	Yes	5	B+
62	Old Town	1 violations	Yes	1	A-
63	Rumford	1 violations	Yes	0	B+
64	Lincoln	1 violations	Yes	4	A
65	Mexico	1 violations	Yes	0	A-
66	East Millinocket	1 violations	Yes	4	A
67	Fryeburg	1 violations	Yes	3	A-
68	Fort Fairfield	1 violations	Yes	10	B+
69	Mechanic Falls	1 violations	Yes	0	B+
70	Newport	1 violations	Yes	54	B+
71	North Berwick	1 violations	Yes	2	B-
72	Lubec	1 violations	Yes	6	B+
73	Baileyville	1 violations	Yes	5	A
74	Machias	1 violations	Yes	0	B+
75	Jay	1 violations	Yes	9	C+
76	Dixfield	1 violations	Yes	8	A-
77	Richmond	1 violations	Yes	11	A
78	Oxford	1 violations	Yes	1	A
79	Norridgewock	1 violations	Yes	6	A
80	Clinton	1 violations	Yes	1	B+
81	Brownville	1 violations	Yes	10	C
82	Kingfield	1 violations	Yes	4	B+
83	Milton	1 violations	Yes	2	A-
84	Winter Harbor	1 violations	Yes	3	A-
85	West Paris	1 violations	Yes	8	C+

FAQ

Frequently asked questions about nitrate in Maine

Is nitrate in Maine tap water dangerous?

Yes — 85 cities in Maine have nitrate-related violations. The EPA MCL is 10 mg/L. Nitrate is especially dangerous for infants under six months, where it can cause methemoglobinemia ("blue baby syndrome"). Adults face lower acute risk, but chronic exposure is linked to thyroid disease and certain cancers.

How can I remove nitrate from my drinking water?

Reverse osmosis, ion exchange, and distillation are effective at removing nitrate. Standard carbon filters (including most pitcher and faucet-mount filters) do NOT remove nitrate. If you rely on a private well in an agricultural area, have your water tested annually for nitrate.

What causes high nitrate levels in Maine water?

Nitrate contamination comes primarily from agricultural fertilizer runoff, septic system leaching, and animal feedlot operations. Rural communities near intensive farming are most at risk. Shallow wells are particularly vulnerable. Heavy rainfall can spike nitrate levels as it washes fertilizer into groundwater and surface water supplies.

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