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Not health advice. Contact your local water utility for concerns.
Data from EPA Water Quality Reports. For official information, contact your water utility or health department.
Compare water quality across 13 counties in Maryland
13 counties ranked by average water quality score
| Rank | County | Avg Score | Grade | Cities | Population | Score Range |
|---|---|---|---|---|---|---|
| 1 | Allegany County | 98 | A+ | 1 | 19,495 | 98 - 98 |
| 2 | Harford County | 93 | A | 1 | 10,594 | 93 - 93 |
| 3 | Carroll County | 92 | A | 1 | 19,960 | 92 - 92 |
| 4 | Baltimore County | 85 | A- | 8 | 905,921 | 79 - 93 |
| 5 | Charles County | 85 | A- | 1 | 81,410 | 85 - 85 |
| 6 | Talbot County | 84 | B+ | 1 | 16,589 | 84 - 84 |
| 7 | Montgomery County | 83 | B+ | 6 | 398,868 | 55 - 93 |
| 8 | Anne Arundel County | 83 | B+ | 5 | 249,998 | 68 - 95 |
| 9 | Prince George's County | 82 | B+ | 6 | 195,364 | 69 - 90 |
| 10 | Frederick County | 82 | B+ | 1 | 78,588 | 82 - 82 |
| 11 | Howard County | 80 | B+ | 2 | 180,628 | 70 - 90 |
| 12 | Wicomico County | 77 | B | 1 | 33,050 | 77 - 77 |
| 13 | Washington County | 50 | D | 1 | 43,527 | 50 - 50 |
1 cities • 19,495 residents
1 cities • 10,594 residents
1 cities • 19,960 residents
8 cities • 905,921 residents
1 cities • 81,410 residents
1 cities • 16,589 residents
6 cities • 398,868 residents
5 cities • 249,998 residents
6 cities • 195,364 residents
1 cities • 78,588 residents
2 cities • 180,628 residents
1 cities • 33,050 residents
See all 13 counties in the ranking table above
Our county-level water quality analysis aggregates data from municipal water systems across Maryland. Each county's score represents the average water quality across all analyzed cities within that county, weighted by population served.
With 13 counties and 35 cities analyzed, this data helps residents understand regional water quality patterns in Maryland. County scores range from 50/100 to 98/100, reflecting the diversity of water sources and treatment infrastructure across the state.
Currently, 1 counties in Maryland have average scores below 70, indicating potential water quality concerns. Residents in these areas should review their city's specific report and consider water filtration options.