Maryland Water Quality
Drinking water data for all 24 counties.
Avg Water Score
50.5
State Grade
D
Counties with Data
24
of 24 total
All Maryland Counties
| County | Water Score |
|---|---|
| Montgomery County | 86.0 |
| Baltimore city | 71.8 |
| Howard County | 70.6 |
| Anne Arundel County | 67.5 |
| Charles County | 62.3 |
| Washington County | 61.5 |
| Frederick County | 61.4 |
| Harford County | 60.8 |
| Prince George's County | 58.5 |
| Carroll County | 57.8 |
| St. Mary's County | 55.6 |
| Calvert County | 50.0 |
| Allegany County | 48.6 |
| Dorchester County | 47.7 |
| Worcester County | 46.7 |
| Kent County | 43.5 |
| Garrett County | 41.8 |
| Wicomico County | 39.2 |
| Queen Anne's County | 35.9 |
| Somerset County | 33.0 |
| Talbot County | 32.1 |
| Caroline County | 27.7 |
| Baltimore County | 26.7 |
| Cecil County | 25.2 |
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Frequently Asked Questions
Which county in Maryland has the best water quality?
Montgomery County has the highest water quality score in Maryland at 86.0/100 (Grade: A), based on EPA SDWIS data.
Which county in Maryland has the most water violations?
Cecil County has among the lowest water quality scores in Maryland at 25.2/100. See the individual county page for detailed violation history.
Is the tap water safe to drink in Maryland?
Maryland has an average water quality score of 50.5/100 based on EPA Safe Drinking Water Act compliance data. Individual county scores vary — check your specific county's page for detailed information.
What contaminants are found in Maryland water supplies?
Drinking water quality varies by county and water system. The EPA Safe Drinking Water Information System (SDWIS) tracks violations for contaminants like lead, nitrates, bacteria, and disinfection byproducts. See individual county pages for specific contaminant and violation history.
Data Source
Water quality data sourced from the EPA Safe Drinking Water Information System (SDWIS) via the ECHO enforcement database. Scores reflect compliance history and health-based violation counts.
Disclaimer: This data is informational only. It is not health, legal, or professional advice. For concerns about your specific water supply, contact your local water utility.