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

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