Maryland Tap Water Quality Report
Water quality grades, lead levels, and violation data for all 615 ZIP codes in Maryland
ZIP Codes
615
Health Violations (5yr)
229
Avg Safety Score
60.7/100
High Lead Risk ZIPs
47.6%
Overview: Drinking Water in Maryland
The tap water quality in Maryland currently sits near the national average, registering a composite safety score of 60.7/100 across 615 monitored ZIP codes. While a significant portion of the state maintains adequate water quality and full compliance with federal standards, 1% of ZIP codes in Maryland have received a failing grade due to recent compliance issues. Monitoring data from the EPA indicates that while the majority of residents receive safe tap water, localized issues remain a challenge for several municipal systems.
Over the past 5 years, water utilities in Maryland have recorded a total of 1,135 violations, of which 229 were strictly health-based. While administrative and reporting violations are common nationwide, health-based violations mean that certain contaminants exceeded the EPA's Maximum Contaminant Levels (MCLs) at some point. Maryland Department of the Environment, which acts as the primary regulatory authority in the state, typically works closely with these utilities to issue boil water advisories or mandate infrastructure upgrades when these limits are breached.
One of the most pressing concerns for Maryland residents is the elevated risk of lead exposure. EPA models and historical monitoring indicate that 47.6% of ZIP codes in Maryland are classified as High or Very High risk for lead. This is frequently associated with older housing stock built before the 1986 federal ban on lead pipes and solder. Residents living in older homes should strongly consider having their tap water independently tested and utilizing a certified NSF/ANSI 53 water filter for drinking and cooking.
Surface Water
50.9%
of ZIP codes
Total Violations
1,135
5-year record
Grade A ZIPs
36
6% of state
Grade F ZIPs
4
1% of state
Water Quality Grade Distribution in Maryland
How do Maryland's 615 ZIP codes stack up by water quality grade?
Water Quality by City in Maryland
Click any city to view ZIP code-level water quality reports
Baltimore
50 ZIPs
Silver Spring
16 ZIPs
Bethesda
11 ZIPs
Gaithersburg
9 ZIPs
Rockville
8 ZIPs
Annapolis
8 ZIPs
Laurel
7 ZIPs
Bowie
7 ZIPs
Hyattsville
7 ZIPs
Hagerstown
7 ZIPs
Frederick
6 ZIPs
Capitol Heights
5 ZIPs
Upper Marlboro
5 ZIPs
Cumberland
5 ZIPs
Waldorf
4 ZIPs
Ridgely
4 ZIPs
Salisbury
4 ZIPs
College Park
3 ZIPs
Greenbelt
3 ZIPs
Germantown
3 ZIPs
Ellicott City
3 ZIPs
Columbia
3 ZIPs
Glen Burnie
3 ZIPs
Towson
3 ZIPs
Southern Md Facility
2 ZIPs
Lanham
2 ZIPs
Beltsville
2 ZIPs
Riverdale
2 ZIPs
Fort Washington
2 ZIPs
Oxon Hill
2 ZIPs
Suitland
2 ZIPs
District Heights
2 ZIPs
Temple Hills
2 ZIPs
Chevy Chase
2 ZIPs
Olney
2 ZIPs
Potomac
2 ZIPs
Kensington
2 ZIPs
Takoma Park
2 ZIPs
Bel Air
2 ZIPs
Hunt Valley
2 ZIPs
๐ Highest Rated ZIP Codes in Maryland
โ Lowest Rated ZIP Codes in Maryland
Common Drinking Water Contaminants in Maryland
The following are common regulated contaminants found in Maryland drinking water based on EPA violation records. Click any contaminant to learn about EPA safety limits and health effects.
Source: EPA Safe Drinking Water Act Maximum Contaminant Level regulations. For the complete list of regulated contaminants and MCLs, see the Water Quality Safety Guide.
Frequently Asked Questions โ Maryland Drinking Water
Is tap water generally safe to drink in Maryland?+
What are the biggest water quality issues in Maryland?+
Who regulates and enforces drinking water standards in Maryland?+
Where does Maryland get its drinking water?+
How do I find the official water quality report for my home in Maryland?+
View All 615 ZIP Codes in Maryland
Browse EPA water quality data for every monitored ZIP code. For faster results, use the search bar above.