Copper Contamination

Copper in Minnesota Drinking Water

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

164

Cities Tested

164

Exceeds Limit

100%

% Exceeds Limit

2.588 mg/L

State Avg

▼ 0% vs national

vs National

217

Health Violations

Analysis

Copper in Minnesota: what the data shows

Minnesota has 164 cities with copper monitoring data. The state average 90th percentile copper level is 2.588 mg/L, compared to 28.808 mg/L nationally — better than the national average. 164 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

Minnesota

100%

164 of 164 cities

← = Exactly at national rate

National avg

100%

3953 of 3953 cities

City Map

Copper data across Minnesota

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 Minnesota

Highest Copper levels (mg/L)

All Cities

All Minnesota cities ranked by copper level

#	City	Level	Exceeds?	Violations	Grade
1	Minneapolis	145.500 mg/L	Yes	2	B-
2	Lake Park	3.700 mg/L	Yes	1	A-
3	Wheaton	3.300 mg/L	Yes	0	A-
4	Graceville	3.000 mg/L	Yes	0	A-
5	Waverly	2.980 mg/L	Yes	1	A
6	Glenville	2.610 mg/L	Yes	10	C+
7	Ironton	2.600 mg/L	Yes	1	B+
8	Morton	2.550 mg/L	Yes	0	C+
9	Tower	2.370 mg/L	Yes	3	A-
10	Redwood Falls	2.360 mg/L	Yes	0	B+
11	Frazee	2.320 mg/L	Yes	0	B+
12	Detroit Lakes	2.300 mg/L	Yes	36	C-
13	Litchfield	2.300 mg/L	Yes	3	A-
14	Maple Plain	2.300 mg/L	Yes	1	A-
15	Bovey	2.280 mg/L	Yes	1	A
16	Wabasso	2.250 mg/L	Yes	0	A-
17	Jasper	2.240 mg/L	Yes	1	A-
18	Hutchinson	2.220 mg/L	Yes	0	A
19	Menahga	2.200 mg/L	Yes	0	A
20	Trimont	2.200 mg/L	Yes	0	A
21	Fulda	2.190 mg/L	Yes	0	B-
22	Gaylord	2.100 mg/L	Yes	0	A-
23	Babbitt	2.100 mg/L	Yes	0	A-
24	Albert Lea	2.080 mg/L	Yes	0	A-
25	White Earth	2.050 mg/L	Yes	20	D
26	Amboy	2.050 mg/L	Yes	14	C+
27	Eden Valley	2.040 mg/L	Yes	0	A
28	Chanhassen	2.000 mg/L	Yes	0	B+
29	Baxter	2.000 mg/L	Yes	0	A+
30	Rush City	2.000 mg/L	Yes	19	D+
31	Eagle Lake	2.000 mg/L	Yes	0	B+
32	New York Mills	1.950 mg/L	Yes	0	A
33	Lake Bronson	1.947 mg/L	Yes	0	B+
34	Buffalo Lake	1.940 mg/L	Yes	1	B+
35	Coleraine	1.930 mg/L	Yes	0	B+
36	Worthington	1.910 mg/L	Yes	0	B+
37	Wells	1.910 mg/L	Yes	0	A
38	Sandstone	1.900 mg/L	Yes	2	A-
39	Lester Prairie	1.900 mg/L	Yes	0	A-
40	Bird Island	1.900 mg/L	Yes	1	A
41	Faribault	1.880 mg/L	Yes	2	B+
42	Pipestone	1.880 mg/L	Yes	2	A
43	Cook	1.870 mg/L	Yes	1	A
44	Marshall	1.832 mg/L	Yes	0	B+
45	Ulen	1.829 mg/L	Yes	0	B+
46	Crosby	1.810 mg/L	Yes	2	B+
47	Grove City	1.810 mg/L	Yes	0	A
48	Coon Rapids	1.800 mg/L	Yes	2	A
49	Buffalo	1.800 mg/L	Yes	0	A-
50	Collegeville	1.800 mg/L	Yes	4	A-
51	Tracy	1.800 mg/L	Yes	0	B+
52	Pine River	1.800 mg/L	Yes	4	A
53	St. Bonifacius	1.790 mg/L	Yes	1	A-
54	Minneota	1.749 mg/L	Yes	0	A-
55	Edina	1.730 mg/L	Yes	1	B+
56	Hawley	1.720 mg/L	Yes	1	A-
57	Minnetrista	1.710 mg/L	Yes	0	A
58	Brooten	1.710 mg/L	Yes	1	A
59	Plymouth	1.700 mg/L	Yes	2	A-
60	Glencoe	1.700 mg/L	Yes	1	A
61	Parkers Prairie	1.700 mg/L	Yes	1	A-
62	Clarissa	1.690 mg/L	Yes	1	A-
63	Eagle Bend	1.690 mg/L	Yes	0	B+
64	Cass Lake	1.670 mg/L	Yes	17	C-
65	Lafayette	1.670 mg/L	Yes	5	B+
66	Renville	1.660 mg/L	Yes	0	A-
67	Watertown	1.640 mg/L	Yes	1	A-
68	Brainerd	1.630 mg/L	Yes	3	B+
69	Glyndon	1.630 mg/L	Yes	0	A
70	Albany	1.626 mg/L	Yes	2	B+
71	Willmar	1.620 mg/L	Yes	3	A-
72	Delano	1.620 mg/L	Yes	0	A
73	Osakis	1.620 mg/L	Yes	2	B-
74	Luverne	1.610 mg/L	Yes	0	A-
75	Cologne	1.610 mg/L	Yes	0	A
76	Big Lake	1.600 mg/L	Yes	1	A
77	Spicer	1.600 mg/L	Yes	2	A-
78	Spring Park	1.600 mg/L	Yes	0	B
79	Pierz	1.600 mg/L	Yes	0	A-
80	Henderson	1.600 mg/L	Yes	1	A
81	Clinton	1.600 mg/L	Yes	2	A-
82	Hills	1.590 mg/L	Yes	0	A
83	Morristown	1.580 mg/L	Yes	1	B+
84	Sartell	1.570 mg/L	Yes	0	A-
85	Clarks Grove	1.570 mg/L	Yes	0	A
86	Motley	1.570 mg/L	Yes	1	A
87	Zumbrota	1.560 mg/L	Yes	0	A-
88	Pelican Rapids	1.560 mg/L	Yes	20	D+
89	Fertile	1.560 mg/L	Yes	0	A
90	Avon	1.557 mg/L	Yes	5	B-
91	Blaine	1.550 mg/L	Yes	3	A-
92	Hibbing	1.550 mg/L	Yes	1	C
93	Rochester	1.540 mg/L	Yes	1	C+
94	Hector	1.540 mg/L	Yes	5	A-
95	Butterfield	1.540 mg/L	Yes	2	A-
96	New Prague	1.530 mg/L	Yes	1	A-
97	Starbuck	1.530 mg/L	Yes	2	A-
98	Elbow Lake	1.530 mg/L	Yes	0	B+
99	Raymond	1.530 mg/L	Yes	0	A-
100	Evansville	1.530 mg/L	Yes	0	A
101	Albertville	1.520 mg/L	Yes	0	A-
102	Roseau	1.520 mg/L	Yes	0	A-
103	Lakefield	1.520 mg/L	Yes	0	A-
104	Pine City	1.510 mg/L	Yes	2	B+
105	Waconia	1.500 mg/L	Yes	0	B+
106	Mound	1.500 mg/L	Yes	1	A-
107	Carver	1.500 mg/L	Yes	0	A-
108	Dilworth	1.500 mg/L	Yes	1	A-
109	Mora	1.500 mg/L	Yes	2	A-
110	Arlington	1.500 mg/L	Yes	1	A-
111	Gibbon	1.500 mg/L	Yes	20	C
112	Argyle	1.500 mg/L	Yes	1	B+
113	Morris	1.490 mg/L	Yes	10	D
114	Madelia	1.490 mg/L	Yes	0	A
115	Madison Lake	1.490 mg/L	Yes	0	A-
116	Alden	1.490 mg/L	Yes	1	B-
117	Kandiyohi	1.490 mg/L	Yes	0	B+
118	Windom	1.470 mg/L	Yes	0	B+
119	Henning	1.470 mg/L	Yes	9	A-
120	Holdingford	1.470 mg/L	Yes	0	A
121	Long Prairie	1.460 mg/L	Yes	1	A
122	Pine Island	1.460 mg/L	Yes	0	A-
123	Hopkins	1.450 mg/L	Yes	0	B+
124	Olivia	1.440 mg/L	Yes	0	A-
125	Appleton	1.430 mg/L	Yes	0	A
126	Belgrade	1.420 mg/L	Yes	0	A-
127	Milaca	1.414 mg/L	Yes	0	B+
128	Nett Lake	1.412 mg/L	Yes	40	D
129	Medford	1.410 mg/L	Yes	6	A-
130	Freeport	1.410 mg/L	Yes	0	A
131	Mankato	1.409 mg/L	Yes	8	F
132	Lakeville	1.400 mg/L	Yes	2	A-
133	Minnetonka	1.400 mg/L	Yes	0	A
134	Lake Benton	1.400 mg/L	Yes	1	A-
135	New Ulm	1.400 mg/L	Yes	0	B+
136	Warren	1.400 mg/L	Yes	2	A-
137	Sauk Centre	1.400 mg/L	Yes	2	A-
138	Wayzata	1.400 mg/L	Yes	0	A-
139	Lonsdale	1.400 mg/L	Yes	2	A
140	Glenwood	1.400 mg/L	Yes	0	C+
141	Ortonville	1.400 mg/L	Yes	0	A-
142	Madison	1.400 mg/L	Yes	0	A-
143	Watkins	1.400 mg/L	Yes	0	A
144	Kimball	1.400 mg/L	Yes	0	A-
145	Karlstad	1.400 mg/L	Yes	0	A-
146	Twin Valley	1.400 mg/L	Yes	0	A
147	Hendricks	1.400 mg/L	Yes	0	B+
148	Randall	1.400 mg/L	Yes	1	A
149	Grand Rapids	1.390 mg/L	Yes	1	B+
150	Braham	1.390 mg/L	Yes	0	A-
151	Fairfax	1.390 mg/L	Yes	0	B+
152	Alexandria	1.380 mg/L	Yes	0	B
153	Wadena	1.380 mg/L	Yes	0	A+
154	Mayer	1.380 mg/L	Yes	0	A-
155	Silver Lake	1.376 mg/L	Yes	0	A
156	Sauk Rapids	1.370 mg/L	Yes	2	B+
157	St. Joseph	1.370 mg/L	Yes	1	A-
158	Sleepy Eye	1.370 mg/L	Yes	0	A
159	Benson	1.370 mg/L	Yes	0	A
160	Orono	1.370 mg/L	Yes	0	B+
161	Moose Lake	1.370 mg/L	Yes	1	B+
162	Brandon	1.370 mg/L	Yes	0	B+
163	Dawson	1.360 mg/L	Yes	1	A-
164	Howard Lake	1.350 mg/L	Yes	1	B

FAQ

Frequently asked questions about copper in Minnesota

Is copper in Minnesota drinking water safe?

164 cities in Minnesota exceed the EPA action level of 1.3 mg/L for copper. The state average is 2.588 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 Minnesota 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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