Copper Contamination

Copper in Washington Drinking Water

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

128

Cities Tested

128

Exceeds Limit

100%

% Exceeds Limit

6.795 mg/L

State Avg

▼ 0% vs national

vs National

261

Health Violations

Analysis

Copper in Washington: what the data shows

Washington has 128 cities with copper monitoring data. The state average 90th percentile copper level is 6.795 mg/L, compared to 28.808 mg/L nationally — better than the national average. 128 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

Washington

100%

128 of 128 cities

← = Exactly at national rate

National avg

100%

3953 of 3953 cities

City Map

Copper data across Washington

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 Washington

Highest Copper levels (mg/L)

All Cities

All Washington cities ranked by copper level

#	City	Level	Exceeds?	Violations	Grade
1	Seattle	610.000 mg/L	Yes	138	F
2	Belfair	8.485 mg/L	Yes	36	C-
3	Eatonville	6.200 mg/L	Yes	2	A-
4	Anderson Island	4.800 mg/L	Yes	1	A-
5	Goldbar	4.400 mg/L	Yes	1	A
6	Tenino	4.000 mg/L	Yes	2	B+
7	Spanaway	3.900 mg/L	Yes	9	C+
8	Sammamish	3.800 mg/L	Yes	6	C-
9	Spokane	3.670 mg/L	Yes	56	F
10	Toppenish	3.380 mg/L	Yes	12	F
11	White Salmon	3.100 mg/L	Yes	9	C+
12	Medical Lake	3.060 mg/L	Yes	9	B-
13	Tumwater	3.000 mg/L	Yes	24	D+
14	Leavenworth	3.000 mg/L	Yes	20	C
15	Wenatchee	2.995 mg/L	Yes	41	D
16	Kelso	2.955 mg/L	Yes	15	F
17	Enumclaw	2.940 mg/L	Yes	1	B+
18	Washougal	2.900 mg/L	Yes	2	B+
19	Oak Harbor	2.800 mg/L	Yes	105	F
20	Bellingham	2.710 mg/L	Yes	54	F
21	Renton	2.700 mg/L	Yes	11	D+
22	Lacey	2.700 mg/L	Yes	125	F
23	Chehalis	2.700 mg/L	Yes	12	F
24	Orting	2.700 mg/L	Yes	1	B+
25	Snoqualime	2.600 mg/L	Yes	4	A-
26	Montesano	2.400 mg/L	Yes	17	F
27	Custer	2.365 mg/L	Yes	12	C+
28	Sequim	2.315 mg/L	Yes	64	F
29	Tacoma	2.300 mg/L	Yes	232	F
30	Kent	2.300 mg/L	Yes	31	F
31	Snohomish	2.300 mg/L	Yes	11	D
32	Burbank	2.300 mg/L	Yes	47	D
33	Startup	2.300 mg/L	Yes	4	A
34	Rainier	2.220 mg/L	Yes	1	A-
35	Buckley	2.200 mg/L	Yes	5	D+
36	Vashon	2.200 mg/L	Yes	24	F
37	Black Diamond	2.200 mg/L	Yes	13	C-
38	Oroville	2.180 mg/L	Yes	7	A-
39	Loon Lake	2.100 mg/L	Yes	14	F
40	Goldendale	2.080 mg/L	Yes	15	B-
41	Clinton	2.070 mg/L	Yes	8	C
42	Cathlamet	2.020 mg/L	Yes	66	C
43	Union	2.010 mg/L	Yes	52	D
44	Woodland	2.000 mg/L	Yes	16	F
45	Quinault	2.000 mg/L	Yes	3	D
46	Acme	2.000 mg/L	Yes	4	A-
47	Rockford	1.940 mg/L	Yes	0	B
48	Federal Way	1.930 mg/L	Yes	2	B
49	Freeland	1.927 mg/L	Yes	129	D
50	Hoquiam	1.915 mg/L	Yes	6	B-
51	Kalama	1.900 mg/L	Yes	0	C+
52	Oakville	1.885 mg/L	Yes	4	F
53	Neah Bay	1.834 mg/L	Yes	22	D
54	Friday Harbor	1.830 mg/L	Yes	153	F
55	Darrington	1.811 mg/L	Yes	4	D
56	Everett	1.800 mg/L	Yes	16	D
57	Camas	1.800 mg/L	Yes	2	C
58	Ellensburg	1.800 mg/L	Yes	19	D
59	Fox Island	1.800 mg/L	Yes	3	B+
60	Coupeville	1.785 mg/L	Yes	448	F
61	Raymond	1.767 mg/L	Yes	76	F
62	Lopez Island	1.760 mg/L	Yes	28	F
63	Trout Lake	1.740 mg/L	Yes	1	B+
64	South Cle Elum	1.730 mg/L	Yes	0	A-
65	Ferndale	1.700 mg/L	Yes	110	F
66	Sultan	1.700 mg/L	Yes	33	B
67	Elma	1.700 mg/L	Yes	5	B-
68	Forks	1.700 mg/L	Yes	8	D
69	Hoodsport	1.700 mg/L	Yes	5	C+
70	Mossyrock	1.630 mg/L	Yes	14	C-
71	Poulsbo	1.600 mg/L	Yes	95	F
72	Longview	1.600 mg/L	Yes	0	B+
73	Yelm	1.600 mg/L	Yes	12	D+
74	Milton	1.600 mg/L	Yes	0	B+
75	Everson	1.600 mg/L	Yes	8	B+
76	Algona	1.600 mg/L	Yes	1	B+
77	Carbonado	1.600 mg/L	Yes	41	B
78	Issaquah	1.590 mg/L	Yes	10	C-
79	Port Orchard	1.587 mg/L	Yes	753	F
80	Anacortes	1.560 mg/L	Yes	10	A-
81	Auburn	1.550 mg/L	Yes	18	D+
82	Chelan	1.550 mg/L	Yes	18	D
83	Lapush	1.550 mg/L	Yes	2	B+
84	Ronald	1.550 mg/L	Yes	5	C+
85	Bothell	1.540 mg/L	Yes	7	F
86	East Wenatchee	1.540 mg/L	Yes	19	B
87	Aberdeen	1.540 mg/L	Yes	10	D
88	Edgewood	1.520 mg/L	Yes	4	A-
89	Moses Lake	1.510 mg/L	Yes	132	F
90	Vancouver	1.500 mg/L	Yes	36	F
91	Centralia	1.500 mg/L	Yes	5	B-
92	Wapato	1.500 mg/L	Yes	11	F
93	Langley	1.500 mg/L	Yes	2	D
94	Deming	1.500 mg/L	Yes	23	D
95	Pe Ell	1.490 mg/L	Yes	16	B-
96	Carlsborg	1.483 mg/L	Yes	2	B-
97	Yakima	1.475 mg/L	Yes	162	F
98	Republic	1.475 mg/L	Yes	181	D
99	Puyallup	1.466 mg/L	Yes	124	F
100	Port Angeles	1.460 mg/L	Yes	19	F
101	Mount Vernon	1.450 mg/L	Yes	191	F
102	Marshall	1.450 mg/L	Yes	22	D
103	Shelton	1.440 mg/L	Yes	158	F
104	Cashmere	1.435 mg/L	Yes	21	F
105	Maple Falls	1.430 mg/L	Yes	35	D+
106	Eastsound	1.425 mg/L	Yes	29	F
107	Brewster	1.420 mg/L	Yes	7	D
108	Kennewick	1.400 mg/L	Yes	78	F
109	Lynden	1.400 mg/L	Yes	235	F
110	Gig Harbor	1.400 mg/L	Yes	62	F
111	Fircrest	1.400 mg/L	Yes	4	A-
112	Napavine	1.400 mg/L	Yes	104	D
113	Granite Falls	1.400 mg/L	Yes	0	A-
114	Castle Rock	1.400 mg/L	Yes	2	A-
115	Rochester	1.400 mg/L	Yes	5	A-
116	Lake Tapps	1.400 mg/L	Yes	6	B-
117	Roy	1.400 mg/L	Yes	0	B+
118	North Bonneville	1.400 mg/L	Yes	0	A-
119	Lake Stevens	1.400 mg/L	Yes	7	C
120	Port Townsend	1.390 mg/L	Yes	15	F
121	Ridgefield	1.386 mg/L	Yes	0	D
122	Olympia	1.380 mg/L	Yes	66	F
123	Tonasket	1.375 mg/L	Yes	134	D
124	Silverdale	1.355 mg/L	Yes	17	F
125	Arlington	1.355 mg/L	Yes	83	F
126	Tahola	1.355 mg/L	Yes	15	D
127	Stevenson	1.350 mg/L	Yes	1	C+
128	Yacolt	1.350 mg/L	Yes	0	A

FAQ

Frequently asked questions about copper in Washington

Is copper in Washington drinking water safe?

128 cities in Washington exceed the EPA action level of 1.3 mg/L for copper. The state average is 6.795 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 Washington 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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