Drinking Water Quality Data

Find data on drinking water quality in Massachusetts. This dataset shows drinking water exceedances for lead by Community Water System and year of exceedance in Massachusetts.

About the Data

Drinking water violations are determined by the Massachusetts Department of Environmental Protection from compliance water sampling. Each row represents a water sample that tested above the EPA Action Level (AL) of 15 ug/L. The AL is compared to the 90th percentile value of all sampling results collected during each monitoring period. (This means that the sample exceeds the action level if more than 10 out of 100 samples taken exceed 15 ug/L.) 

Each record also contains descriptive information about the Community Water System, including the city/town served, number of people served, the community population, and the percent of the community population served by the Community Water System.

Image that shows the various forms of oppression that impact the various types of social determinants of health, that then impact health outcomes.


As you look at data on this webpage, you may see differences among population groups. The differences are especially noticeable between white people and people of color.

These differences exist because of structural racism. These differences are NOT because of an individual’s choices, behaviors, or identity.

Systems of oppression, such as racism, cause harm to everyone. They also influence the social determinants of health (SDoH), which impact health outcomes. See Figure 1.

It is important to keep these notes in mind when looking at the data and using it to inform public health efforts.

If you decide to share these data, remember to use racial equity context and framing. The DPH Racial Equity Data Road Map is one resource that can help.

About Drinking Water Quality Data

Lead exceedance data are published for Community Water Systems only. Private wells and transient non-community water systems may also be an important source of exposure. These data should not be used to identify single problematic water systems. To identify regulatory or compliance issues with single water systems contact the MA DEP.  Multiple Community Water Systems can serve the same city/county and multiple cities/counties can be served by a single Community Water System. Measures do not account for the variability in sampling and numbers of sampling repeats. Furthermore, concentrations in drinking water cannot be directly converted to exposure because water consumption varies by climate, level of physical activity, and between people.  Due to errors in estimating populations, the measures may overestimate or underestimate the number of affected people.

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Additional Resources

Contact   for Drinking Water Quality Data


Population Health Information Tool Information Email Population Health Information Tool (PHIT) at DPH.PHIT@mass.gov


250 Washington Street, Boston, MA 02108

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