countyscore

Water Quality · Oregon

Best Water Quality Counties in Oregon 2026

Ranked by EPA drinking water health violations.

Top 10 — Water Quality in Oregon

Score reflects water quality only — not overall county quality.

1Gilliam County, OR
86
2Harney County, OR
86
3Jefferson County, OR
86
4Sherman County, OR
86
5Union County, OR
86
6Wallowa County, OR
86
7Wheeler County, OR
86
8Washington County, OR
67.7
9Multnomah County, OR
66.8
10Deschutes County, OR
60.1

All Oregon Counties — Water Quality Rankings

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

#CountyWater Quality ScoreOverall Score
1Gilliam County, OR
86
44.9
2Harney County, OR
86
55.6
3Jefferson County, OR
86
48.1
4Sherman County, OR
86
55.3
5Union County, OR
86
43.2
6Wallowa County, OR
86
63.9
7Wheeler County, OR
86
55.3
8Washington County, OR
67.7
41.2
9Multnomah County, OR
66.8
44.4
10Deschutes County, OR
60.1
44.3
11Linn County, OR
53.8
35
12Marion County, OR
50.4
30.4
13Klamath County, OR
50.1
36.7
14Hood River County, OR
49.3
48.2
15Umatilla County, OR
45.9
33.2
16Polk County, OR
45.5
43.3
17Lake County, OR
42.7
65.3
18Clackamas County, OR
37.6
36.5
19Crook County, OR
35
48.1
20Yamhill County, OR
34
40.9
21Morrow County, OR
33.9
45.1
22Clatsop County, OR
32.7
37.4
23Grant County, OR
29.4
64.1
24Lane County, OR
29
30.8
25Douglas County, OR
28.5
36.8
26Baker County, OR
28.4
36.3
27Lincoln County, OR
27.8
34.2
28Tillamook County, OR
27.3
43.5
29Benton County, OR
21.6
35.8
30Jackson County, OR
19.6
31.5
31Josephine County, OR
16.9
35.7
32Wasco County, OR
15.9
32.3
33Coos County, OR
14
29.2
34Columbia County, OR
13.9
43
35Curry County, OR
13.9
41.9
36Malheur County, OR
11.4
37.8

Explore More

Best overall counties in OregonFull Water Quality data on WaterByCounty