countyscore

Water Quality · Washington

Best Water Quality Counties in Washington 2026

Ranked by EPA drinking water health violations.

Top 10 — Water Quality in Washington

Score reflects water quality only — not overall county quality.

1Asotin County, WA
86
2Columbia County, WA
86
3Douglas County, WA
86
4Jefferson County, WA
86
5Lincoln County, WA
86
6Pacific County, WA
86
7Pend Oreille County, WA
86
8Snohomish County, WA
86
9Wahkiakum County, WA
86
10Whitman County, WA
86

All Washington Counties — Water Quality Rankings

39 counties ranked by water quality score. Overall Score shown for context.

#CountyWater Quality ScoreOverall Score
1Asotin County, WA
86
45
2Columbia County, WA
86
44.8
3Douglas County, WA
86
45.1
4Jefferson County, WA
86
48.6
5Lincoln County, WA
86
60.9
6Pacific County, WA
86
45.7
7Pend Oreille County, WA
86
54.7
8Snohomish County, WA
86
41.6
9Wahkiakum County, WA
86
69.1
10Whitman County, WA
86
49.8
11King County, WA
71.1
39.4
12Clark County, WA
69.5
38.2
13Chelan County, WA
68
41.9
14Kitsap County, WA
67.5
40.1
15Cowlitz County, WA
66.4
36
16Kittitas County, WA
66.4
41.8
17Skagit County, WA
65.3
37.3
18Spokane County, WA
63.8
36.8
19Clallam County, WA
63
40.4
20Yakima County, WA
62.8
30.4
21Mason County, WA
62.2
40.1
22Adams County, WA
60.1
37.4
23Franklin County, WA
58.1
34.3
24Pierce County, WA
57.1
33.7
25Skamania County, WA
54
57.7
26Grays Harbor County, WA
53.6
36.2
27Klickitat County, WA
53.5
52.7
28Walla Walla County, WA
53.3
36.9
29Thurston County, WA
50.8
37.7
30Lewis County, WA
49.9
37.2
31Okanogan County, WA
49.7
45.9
32Whatcom County, WA
45.3
38
33Grant County, WA
42.5
32.8
34Benton County, WA
41
36.8
35Stevens County, WA
40.7
55.1
36Island County, WA
8.2
50.7
37San Juan County, WA
4.1
55.4
38Garfield County, WA
3.6
54.4
39Ferry County, WA
2
58

Explore More

Best overall counties in WashingtonFull Water Quality data on WaterByCounty