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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?

A
36 ZIP codes6%
B
93 ZIP codes15%
C
271 ZIP codes44%
D
211 ZIP codes34%
F
4 ZIP codes1%

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.

Stage 2 DBP RuleConsumer Confidence Report RuleHaloacetic Acids (HAA5)Total Trihalomethanes (TTHM)Stage 1 DBP RuleContaminant 0700ChloriteFecal Coliform

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?+
Yes, for the majority of residents, tap water in Maryland is treated, heavily regulated, and safe to drink. However, safety varies significantly by location. Statewide, 36 ZIP codes earn an "A" grade for perfect compliance, while 4 earn an "F" due to historical violations. It is essential to search your specific ZIP code above to view the exact compliance record for your local water utility.
What are the biggest water quality issues in Maryland?+
Based on a 5-year analysis of EPA violation data, the primary water quality challenges in Maryland include managing 229 health-based violations statewide and addressing infrastructure age. Additionally, 47.6% of ZIP codes in the state are rated as having a High or Very High probability of lead exposure risk, which is a key metric residents should monitor.
Who regulates and enforces drinking water standards in Maryland?+
Drinking water in Maryland is primarily regulated by Maryland Department of the Environment under a primacy agreement with the U.S. Environmental Protection Agency (EPA). The EPA sets the federal baseline standards (Maximum Contaminant Levels) through the Safe Drinking Water Act, while Maryland Department of the Environment conducts the day-to-day monitoring, issues compliance orders, and enforces penalties against local water systems that fail to meet these standards.
Where does Maryland get its drinking water?+
Water sources in Maryland vary widely by municipality. Statewide, approximately 50.9% of the monitored ZIP codes rely on surface water sources (such as rivers, lakes, and reservoirs), which require extensive filtration and disinfection. The remaining systems primarily rely on groundwater pumped from underground aquifers, which is naturally filtered but can be susceptible to agricultural runoff or naturally occurring minerals.
How do I find the official water quality report for my home in Maryland?+
You can enter your ZIP code in our search box above for a detailed, easy-to-read report based on EPA data. Furthermore, your local water utility is required by federal law to distribute an annual Consumer Confidence Report (CCR) by July 1 of each year. You can contact your utility directly to request this document, which outlines exact contaminant measurements from the previous year.
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.

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+ 315 more ZIP codes โ€” please search by city above