Copper Contamination

Copper in Oklahoma Drinking Water

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

Cities Tested

Exceeds Limit

100%

% Exceeds Limit

1.998 mg/L

State Avg

▼ 0% vs national

vs National

351

Health Violations

Analysis

Copper in Oklahoma: what the data shows

Oklahoma has 68 cities with copper monitoring data. The state average 90th percentile copper level is 1.998 mg/L, compared to 28.808 mg/L nationally — better than the national average. 68 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

Oklahoma

100%

68 of 68 cities

← = Exactly at national rate

National avg

100%

3953 of 3953 cities

City Map

Copper data across Oklahoma

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 Oklahoma

Highest Copper levels (mg/L)

All Cities

All Oklahoma cities ranked by copper level

#	City	Level	Exceeds?	Violations	Grade
1	Haworth	9.700 mg/L	Yes	67	D
2	Stuart	6.350 mg/L	Yes	96	C-
3	Stillwater	3.300 mg/L	Yes	72	F
4	Tonkawa	3.300 mg/L	Yes	6	B-
5	Newkirk	2.620 mg/L	Yes	39	F
6	Perkins	2.600 mg/L	Yes	1	D
7	Wynnewood	2.400 mg/L	Yes	85	D
8	Cashion	2.400 mg/L	Yes	2	A-
9	Madill	2.300 mg/L	Yes	178	F
10	Talihina	2.296 mg/L	Yes	295	D
11	Wayne	2.290 mg/L	Yes	28	C
12	Bernice	2.210 mg/L	Yes	6	C
13	Konawa	2.200 mg/L	Yes	19	D
14	Hendrix	2.160 mg/L	Yes	5	D
15	Okarche	2.150 mg/L	Yes	236	F
16	Nashoba	2.142 mg/L	Yes	82	F
17	Ponca City	2.102 mg/L	Yes	23	F
18	Collinsville	2.100 mg/L	Yes	24	C+
19	Idabel	2.100 mg/L	Yes	123	D
20	Haskell	2.060 mg/L	Yes	109	D
21	Clayton	2.030 mg/L	Yes	270	D
22	Norman	2.024 mg/L	Yes	52	F
23	Edmond	2.005 mg/L	Yes	86	F
24	Caddo	1.980 mg/L	Yes	11	C-
25	Kremlin	1.980 mg/L	Yes	25	F
26	Cookson	1.970 mg/L	Yes	102	D
27	Carter	1.900 mg/L	Yes	28	B+
28	Okeene	1.850 mg/L	Yes	114	D+
29	Pond Creek	1.741 mg/L	Yes	3	C+
30	Cleveland	1.740 mg/L	Yes	182	F
31	Wagoner	1.730 mg/L	Yes	141	F
32	Twin Oaks	1.725 mg/L	Yes	1	C+
33	Cache	1.720 mg/L	Yes	64	F
34	Choctaw	1.720 mg/L	Yes	3	F
35	Hennessey	1.692 mg/L	Yes	70	B-
36	Colbert	1.682 mg/L	Yes	4	C+
37	Geary	1.674 mg/L	Yes	74	D
38	Shawnee	1.660 mg/L	Yes	124	D
39	Eufaula	1.660 mg/L	Yes	374	F
40	Fort Gibson	1.606 mg/L	Yes	153	F
41	Jay	1.600 mg/L	Yes	87	D
42	Wellston	1.580 mg/L	Yes	71	F
43	Coleman	1.562 mg/L	Yes	3	B+
44	Henryetta	1.560 mg/L	Yes	116	F
45	Checotah	1.555 mg/L	Yes	365	D
46	Mcalester	1.550 mg/L	Yes	670	F
47	Enid	1.500 mg/L	Yes	33	F
48	Heavener	1.497 mg/L	Yes	59	D
49	Lawton	1.490 mg/L	Yes	23	F
50	Earlsboro	1.490 mg/L	Yes	4	C+
51	Red Rock	1.490 mg/L	Yes	166	D
52	Lahoma	1.481 mg/L	Yes	0	A-
53	Dewey	1.480 mg/L	Yes	23	F
54	Achille	1.480 mg/L	Yes	2	A-
55	Calumet	1.460 mg/L	Yes	117	D
56	Fairview	1.440 mg/L	Yes	97	D
57	Afton	1.440 mg/L	Yes	89	F
58	Lexington	1.420 mg/L	Yes	16	F
59	Bartlesville	1.410 mg/L	Yes	217	F
60	Kingfisher	1.410 mg/L	Yes	38	D
61	Stilwell	1.400 mg/L	Yes	18	C
62	Marshall	1.400 mg/L	Yes	10	B-
63	Weleetka	1.400 mg/L	Yes	187	D
64	Watonga	1.390 mg/L	Yes	27	C+
65	Claremore	1.388 mg/L	Yes	153	F
66	Porum	1.383 mg/L	Yes	45	B-
67	Stillwell	1.380 mg/L	Yes	0	B+
68	Crescent	1.370 mg/L	Yes	82	C+

FAQ

Frequently asked questions about copper in Oklahoma

Is copper in Oklahoma drinking water safe?

68 cities in Oklahoma exceed the EPA action level of 1.3 mg/L for copper. The state average is 1.998 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 Oklahoma 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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