Maryland Tap Water Quality Rankings 2026: 4th in Nation | WaterQ
Maryland ranks 4th out of 50 states for drinking water quality, receiving an overall grade of A with an average score of 91. The state's 165 water systems serve a population of over 5.4 million residents across its diverse Mid-Atlantic, Chesapeake Bay coastal, and dense Baltimore/DC urban corridor regions. Despite its high ranking, the state has recorded 4,133 violations, highlighting the ongoing need for monitoring and infrastructure maintenance.
Key Findings for Maryland
Reviewing EPA SDWIS data for 2026, here's what defines Maryland's water quality landscape:
- In the dense urban corridors of the Baltimore/DC metro area, aging water infrastructure can present risks such as lead service lines or water main issues.
- Agricultural runoff in the Mid-Atlantic and Chesapeake Bay coastal regions can lead to elevated levels of nitrates and pesticides in nearby water sources.
- Coastal and low-lying areas in the state may face challenges related to disinfection byproducts resulting from treatment processes or seasonal runoff.
Most Common Contaminants in Maryland
Here's what Maryland residents should know about the contaminants most relevant to their water:
Lead
Lead can enter drinking water through the corrosion of plumbing materials and lead service lines, which are more common in areas with older housing stock. Exposure is generally localized to individual properties rather than widespread at the system source.
Nitrate
Nitrate is a common contaminant in agricultural areas, where fertilizer runoff and waste can leach into groundwater and surface water supplies. Elevated nitrate levels are a particular concern for private well owners in rural parts of the state.
Disinfection Byproducts
These chemical compounds form when chlorine or other disinfectants used to treat drinking water react with naturally occurring organic matter in source water. Widespread surface water systems are especially monitored for these byproducts to ensure they remain within safe limits.
Maryland's Best and Worst Cities for Water Quality
To see how individual municipalities perform, residents can explore our comprehensive city-by-city database. This breakdown details the specific test results, local infrastructure issues, and compliance records for each community's public water systems. Explore the full breakdown on our Maryland water systems page.
What Maryland Residents Should Do
Given Maryland's 4th place ranking, here's what matters most for residents:
- Search for your local water system in the EPA database to review its recent testing results and compliance history.
- If your home is served by a private well, test the water annually for common contaminants like nitrates and bacteria.
- Identify if your home has lead service lines or plumbing, and consider using an NSF-certified filter to reduce lead and other specific contaminants.
- Regularly check for local water quality alerts and utility updates to stay informed about temporary advisories.
Frequently Asked Questions
How does Maryland water quality compare to other states?
Maryland has some of the highest-rated drinking water in the nation, ranking 4th out of the 50 states. It received a grade of A with an average score of 91 based on water system performance data.
What are the most common contaminants in Maryland tap water?
The most common contaminant risks are lead from aging plumbing, nitrates from agricultural runoff in rural areas, and disinfection byproducts in treated surface water. These reflect regional patterns rather than statewide contamination.
Is it safe to drink tap water in Maryland?
With an overall grade of A, Maryland's public drinking water generally meets high safety standards. However, localized issues like lead service lines or private well contamination can still affect individual homes, so testing and targeted filtration are recommended.
Source: EPA SDWIS 2026 Compliance Data and WaterQ National Database. For more information on our ranking process, visit our state rankings page.