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.
All Maryland Counties — Water Quality Rankings
24 counties ranked by water quality score. Overall Score shown for context.
| # | 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 |