Tap water in Maryland is generally safe to drink, as the vast majority of the public water supply is heavily regulated and consistently meets federal quality standards. Safety, however, is not uniform across the state and depends significantly on the source of the water and the condition of the household plumbing. While water drawn from public systems is treated and tested for a wide range of contaminants, private wells and aging infrastructure present localized risks that consumers must actively manage.
The Regulatory Landscape Ensuring Maryland Water Safety
The safety of Maryland’s public drinking water begins with the federal Safe Drinking Water Act (SDWA), which grants the Environmental Protection Agency (EPA) the authority to establish national standards for over 90 contaminants that could harm public health. These standards include Maximum Contaminant Levels (MCLs) for substances that pose both acute risks, such as E. coli or nitrates, and chronic risks, which are based on long-term exposure over many decades. The SDWA requires public water systems to have the necessary infrastructure and operational protocols to ensure compliance with these federal limits.
The Maryland Department of the Environment (MDE) implements the SDWA and enforces water quality regulations. MDE oversees the more than 3,200 public water systems across the state, including community water systems that serve residents year-round. MDE routinely conducts on-site inspections, issues permits, and requires regular sampling for contaminants to ensure compliance.
Maryland’s public water systems maintain a high level of compliance with the requirements of the SDWA. The regulatory system ensures that water is treated to prevent waterborne diseases from microbes like Giardia lamblia and Cryptosporidium, which are often found in surface water sources like rivers and reservoirs.
Understanding Localized Risks and Specific Contaminants
Even with strong source water treatment, risks to drinking water quality often emerge at the local level. The primary localized concern for residents served by public water is the presence of lead, which leaches into the water from aging infrastructure. While the source water is usually lead-free, older urban areas, such as Baltimore or inner suburbs, may still have lead service lines connecting the main to the home, or lead solder and brass fittings within the household plumbing.
Corrosive water dissolves lead from older pipes, especially when the water has been sitting stagnant overnight. The federal Lead and Copper Rule mandates monitoring at customer taps and requires water systems to implement corrosion control measures. This does not guarantee zero lead at every faucet, particularly in homes built before 1986.
Approximately 350,000 Maryland households rely on private wells, which are not regulated by the EPA or MDE. Well water is susceptible to contamination from agricultural runoff, introducing high levels of nitrates, and from septic systems, introducing harmful bacteria like E. coli. The Eastern Shore and parts of Western Maryland are particularly vulnerable to these groundwater issues.
Per- and polyfluoroalkyl substances (PFAS) are emerging contaminants that can affect both public and private water sources. These persistent “forever chemicals” have been detected in groundwater and wells in areas like Elkton and Salisbury. PFAS exposure has been linked to potential health effects, and the EPA has established health advisories for these compounds.
Steps for Assessing Your Household Water Quality
Residents who receive water from a public system can begin their assessment by reviewing their annual Consumer Confidence Report (CCR). Community water systems are required to distribute this report to customers by July 1st each year. The CCR explains where the water originates, lists any contaminants that were detected, and notes whether the system had any violations of federal or state standards.
For private well owners, the responsibility for water safety falls entirely on the homeowner, making routine testing a necessity. The EPA and MDE recommend that well water be tested at least once a year, minimally for total coliform bacteria, nitrates, and pH levels. Well owners should contact a laboratory certified by the MDE to perform these tests and should also test any time they notice a change in the water’s taste, odor, or appearance.
If a home has older plumbing or if a CCR or well test indicates the presence of a contaminant like lead or PFAS, a point-of-use filtration system can be a useful precautionary measure. Granular Activated Carbon filters and Reverse Osmosis systems are known to be effective at removing certain contaminants, including PFAS, and can be installed at the tap to provide an extra layer of protection.