countyscore

Best Water Quality Counties in Louisiana

EPA drinking water health violations and safety grades Compare rankings across all 64 counties.

Average Water Quality Score
30/100
Top County
Assumption Parish
Counties Ranked
63

Top 10

#1
Assumption Parish
LA
86/100
#2
Lafourche Parish
LA
86/100
#3
St. Bernard Parish
LA
86/100
#4
St. Charles Parish
LA
86/100
#5
St. John the Baptist Parish
LA
86/100
#6
Terrebonne Parish
LA
86/100
#7
East Baton Rouge Parish
LA
70/100
#8
Jefferson Parish
LA
69/100
#9
Orleans Parish
LA
66/100
#10
West Baton Rouge Parish
LA
65/100

All Louisiana Counties Ranked

#CountyWater Quality ScoreOverall Score
1Assumption Parish, LA
86
69.4
2Lafourche Parish, LA
86
47.1
3St. Bernard Parish, LA
86
42.5
4St. Charles Parish, LA
86
48.8
5St. John the Baptist Parish, LA
86
43.2
6Terrebonne Parish, LA
86
43.5
7East Baton Rouge Parish, LA
70.4
31.4
8Jefferson Parish, LA
69
34.2
9Orleans Parish, LA
65.8
24
10West Baton Rouge Parish, LA
65.3
46.9
11West Feliciana Parish, LA
62.8
65.8
12Jefferson Davis Parish, LA
58.3
53.1
13East Feliciana Parish, LA
51.3
61.8
14Rapides Parish, LA
46.5
36
15Beauregard Parish, LA
44.8
57.1
16Calcasieu Parish, LA
43.6
44.6
17Lafayette Parish, LA
41.1
34.3
18Livingston Parish, LA
40.6
43.3
19Pointe Coupee Parish, LA
40
54.3
20St. Tammany Parish, LA
36.4
44.1
21Vernon Parish, LA
36.3
64.4
22Tangipahoa Parish, LA
35.4
34.1
23Iberia Parish, LA
33.5
59.3
24Vermilion Parish, LA
27.1
57.6
25Avoyelles Parish, LA
27
58.3
26Catahoula Parish, LA
25.7
58.9
27Washington Parish, LA
25.5
46.4
28Caddo Parish, LA
23.8
47.7
29St. Helena Parish, LA
23.8
46.9
30St. Landry Parish, LA
23.7
46.1
31St. James Parish, LA
23.4
51.8
32Webster Parish, LA
23.1
58.1
33Ascension Parish, LA
21.8
41.2
34Bossier Parish, LA
21.6
36.2
35Ouachita Parish, LA
20.8
35.3
36St. Martin Parish, LA
19.8
47.6
37Allen Parish, LA
18.9
68.4
38Franklin Parish, LA
18.8
54
39Claiborne Parish, LA
18.7
68.8
40Evangeline Parish, LA
16.9
50.6
41West Carroll Parish, LA
16.8
68.4
42Acadia Parish, LA
16
55.4
43St. Mary Parish, LA
14.4
48.9
44Iberville Parish, LA
14.1
52.2
45Madison Parish, LA
14
56.6
46Lincoln Parish, LA
12.5
49.8
47Plaquemines Parish, LA
10.5
54.9
48Richland Parish, LA
9.8
58.1
49Morehouse Parish, LA
6.6
42.2
50Natchitoches Parish, LA
5.6
63.1
51De Soto Parish, LA
5.2
65.1
52Grant Parish, LA
5
53.8
53East Carroll Parish, LA
4.9
63.3
54Red River Parish, LA
3.1
64.2
55Jackson Parish, LA
3
64.2
56Caldwell Parish, LA
2.9
58.8
57Concordia Parish, LA
2.8
45.8
58Bienville Parish, LA
2.3
64.2
59Cameron Parish, LA
2.3
75.1
60Sabine Parish, LA
1.8
63.8
61Tensas Parish, LA
1.7
59.6
62Union Parish, LA
1.2
66.8
63Winn Parish, LA
0.9
67.8

Data Source

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