Massachusetts Department of Public Health seal Massachusetts Environmental Public Health Tracking

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Drinking water quality is an important public health issue since contamination in a single public water system can expose many people at once. People can be exposed to contaminants in drinking water not only by drinking the water, but also by eating foods prepared with the water, breathing water droplets or chemicals released from the water while showering, or absorbing chemicals through the skin while bathing. If a person is exposed to a high enough level of a contaminant, they may become ill. There are many types of health problems that can result from exposure to contaminants. The risk of developing a specific disease depends on many factors, including:

  • The specific contaminant
  • The level and potency of that contaminant
  • The way the contaminant enters the body (for example, drinking, breathing, and/or skin absorption)
  • The person's individual susceptibility
  • Sensitive people such as the elderly, children, and pregnant women are more likely to suffer health effects than the rest of the population

The majority of Americans are provided with high quality drinking water. There are approximately 170,000 public water systems in the United States. All public water systems have at least 15 service connections or serve at least 25 people per day for 60 days of the year. There are two types of public water systems:

  • Community water systems serve the same people year round. Most residences, including homes, apartments, and condos in cities, towns, and mobile home parks are served by community water systems.
  • Non-community water systems do not serve the same people year-round. Schools with their own systems and campgrounds are examples of non-community water systems.

The vast majority of people in the United States (263 million) receive their water from a community water system. While people also drink from non-community systems, community water systems provide the most risk to exposure from contaminants. Therefore, community water systems are the focus of this tracking project.

The Massachusetts Department of Environmental Protection's (MassDEP) Drinking Water Program ensures that the drinking water delivered by community water systems in Massachusetts complies with national standards, or Maximum Contaminant Levels (MCL), set by the U.S. Environmental Protection Agency (U.S. EPA). There are water quality standards and monitoring requirements for over 90 contaminants. MassDEP may adopt or revise standards established by the U.S. EPA, or may adopt a more stringent standard or guideline based on an independent review of primary or secondary data. Public water suppliers determine compliance with drinking water standards by measuring the level of bacteria, various metals, and chemicals in drinking water to ensure safety and quality. If the level of contaminants exceeds drinking water standards established by the U.S. EPA or MassDEP, then the water supplier must notify the MassDEP and take corrective action.

Information on drinking water contaminants for Massachusetts community water systems is provided on this website. Here is a list of all Massachusetts community public water systems and the communities served.

The table below lists the contaminants for which information is available.

Available Information by Community Water System and Year, Summary table showing drinking water violations for Arsenic, Nitrates, Disinfection Byproducts and Lead
Contaminant Regulatory Violations Concentrations Number of Residents Served
Contaminant Arsenic Regulatory Violations X Concentrations X Number of Residents Served X
Contaminant Atrazine Regulatory Violations X Concentrations X Number of Residents Served X
Contaminant Di(2-ethylhexyl) phthalate (DEHP) Regulatory Violations X Concentrations X Number of Residents Served X
Contaminant Disinfection Byproducts Regulatory Violations X Concentrations X Number of Residents Served X
Contaminant Lead Regulatory Violations Only exceedances of action levels, which do not represent violations Exceedance level only Number of Residents Served X
Contaminant Nitrates Regulatory Violations X Concentrations X Number of Residents Served X
Contaminant Tetracholorethene (PCE) Regulatory Violations X Concentrations X Number of Residents Served X
Contaminant Tricholorethene (TCE) Regulatory Violations X Concentrations X Number of Residents Served X
Contaminant Uranium Regulatory Violations X Concentrations X Number of Residents Served X

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