countyscore

Water Quality · Maryland

Best Water Quality Counties in Maryland 2026

Ranked by EPA drinking water health violations.

Top 10 — Water Quality in Maryland

Score reflects water quality only — not overall county quality.

1Montgomery County, MD
86
2Baltimore city, MD
71.8
3Howard County, MD
70.6
4Anne Arundel County, MD
67.5
5Charles County, MD
62.3
6Washington County, MD
61.5
7Frederick County, MD
61.4
8Harford County, MD
60.8
9Prince George's County, MD
58.5
10Carroll County, MD
57.8

All Maryland Counties — Water Quality Rankings

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

#CountyWater Quality ScoreOverall Score
1Montgomery County, MD
86
46.9
2Baltimore city, MD
71.8
24.8
3Howard County, MD
70.6
48.8
4Anne Arundel County, MD
67.5
45.6
5Charles County, MD
62.3
48.2
6Washington County, MD
61.5
44.6
7Frederick County, MD
61.4
49.9
8Harford County, MD
60.8
50.1
9Prince George's County, MD
58.5
32.5
10Carroll County, MD
57.8
57
11St. Mary's County, MD
55.6
52.3
12Calvert County, MD
50
59.1
13Allegany County, MD
48.6
49.8
14Dorchester County, MD
47.7
47
15Worcester County, MD
46.7
48.4
16Kent County, MD
43.5
52.8
17Garrett County, MD
41.8
62.7
18Wicomico County, MD
39.2
39.4
19Queen Anne's County, MD
35.9
58.9
20Somerset County, MD
33
40.2
21Talbot County, MD
32.1
56.9
22Caroline County, MD
27.7
42
23Baltimore County, MD
26.7
38.3
24Cecil County, MD
25.2
42.2

Explore More

Best overall counties in MarylandFull Water Quality data on WaterByCounty