countyscore

Best Water Quality Counties in South Dakota

EPA drinking water health violations and safety grades Compare rankings across all 66 counties.

Average Water Quality Score
57/100
Top County
Aurora County
Counties Ranked
63

Top 10

#1
Aurora County
SD
86/100
#2
Bennett County
SD
86/100
#3
Charles Mix County
SD
86/100
#4
Clark County
SD
86/100
#5
Davison County
SD
86/100
#6
Douglas County
SD
86/100
#7
Faulk County
SD
86/100
#8
Gregory County
SD
86/100
#9
Hand County
SD
86/100
#10
Harding County
SD
86/100

All South Dakota Counties Ranked

#CountyWater Quality ScoreOverall Score
1Aurora County, SD
86
61.3
2Bennett County, SD
86
43
3Charles Mix County, SD
86
55.3
4Clark County, SD
86
63
5Davison County, SD
86
43.3
6Douglas County, SD
86
61.5
7Faulk County, SD
86
68.8
8Gregory County, SD
86
61.9
9Hand County, SD
86
72.3
10Harding County, SD
86
74.8
11Hughes County, SD
86
42.3
12Hyde County, SD
86
57.4
13Jackson County, SD
86
66.7
14Jerauld County, SD
86
65.9
15Jones County, SD
86
58.8
16Kingsbury County, SD
86
66.5
17Lake County, SD
86
51
18Lyman County, SD
86
59.4
19Marshall County, SD
86
64.5
20McCook County, SD
86
58.8
21Perkins County, SD
86
66.3
22Potter County, SD
86
66.2
23Sanborn County, SD
86
61.6
24Stanley County, SD
86
60.1
25Sully County, SD
86
70
26Union County, SD
86
51.5
27Walworth County, SD
86
50.6
28Ziebach County, SD
86
63.9
29Minnehaha County, SD
70.4
49.5
30Codington County, SD
64.1
40.4
31Clay County, SD
57.7
37.1
32Brookings County, SD
57.2
48.5
33Lincoln County, SD
53.2
34.4
34Lawrence County, SD
48.1
43.9
35Beadle County, SD
47.6
43.2
36Dewey County, SD
46.9
54.1
37Turner County, SD
45.4
59.3
38Grant County, SD
44.5
68.9
39Pennington County, SD
41.3
27.8
40Yankton County, SD
41.3
42.9
41Meade County, SD
38.9
34.5
42Edmunds County, SD
38.8
62.8
43Day County, SD
38.6
60.5
44Butte County, SD
33.2
43.5
45Brown County, SD
32.5
42.5
46Moody County, SD
32.5
50.5
47Hutchinson County, SD
28.5
65.7
48Bon Homme County, SD
27.2
61.9
49McPherson County, SD
26.9
60.5
50Hanson County, SD
25.3
62.2
51Tripp County, SD
24.6
50.7
52Miner County, SD
22.5
68
53Fall River County, SD
21.4
46.6
54Brule County, SD
21
46.4
55Deuel County, SD
19.4
67.3
56Corson County, SD
19.3
49
57Campbell County, SD
17.8
62.9
58Custer County, SD
17
50.7
59Spink County, SD
16.5
58.6
60Mellette County, SD
15.7
51.9
61Haakon County, SD
13.4
65.5
62Hamlin County, SD
11.5
57.1
63Roberts County, SD
10.6
52.8

Data Source

Water Quality data from WaterByCounty. See full details at WaterByCounty. Data updated February 2026.