What's in my drinking water?

Learn how Massachusetts public water supplies are tested. Find out who to contact for more information about your drinking water. Read about keeping your drinking water clean.

Table of Contents

Public water supply testing in Massachusetts

Massachusetts has some of the highest quality drinking water in the country and some of the strictest standards. 

The Massachusetts Department of Environmental Protection (MassDEP) requires your local water supplier to perform ongoing tests for:

  • Bacteria,
  • Lead and other heavy metals
  • Herbicides and pesticides
  • Industrial solvents

If testing reveals contaminants at levels above the federal standard, the water supplier is required to notify customers. If bacteria or chemicals are found in levels that pose a threat to your health, the water supply is treated to remove the contaminants or taken out of service if the problem can't be solved immediately.

Additional Resources   for Public water supply testing in Massachusetts

Public notification of contaminated drinking water

Water system owners and public water suppliers are required by law to notify the public if their water violates drinking water standards and is a risk to public health. Notifications by mail to those using the water system are required. More notifications of drinking water violations may be provided:

  • In public places
  • In the newspaper or through local media
  • On the internet
  • Communicated via e-mail

If your water comes from a private well you will not receive a notification about contaminants in the water.

Additional Resources   for Public notification of contaminated drinking water

Private well drinking water

There are some people whose water comes from private wells. MassDEP and the U.S. Environmental Protection Agency (EPA) do not regulate private wells.  Local Boards of Health establish regulations for private wells, which can include regulations for:

  • Siting the well
  • Well construction
  • Water quality
  • Water quantity

Boards of Health do not test your private well water. You are highly encouraged to get your water tested at a MassDEP certified laboratory for private drinking water. 

Your local Board of Health may require you to get your water tested for certain contaminants. Contact your local Board of Health prior to getting your water tested. 

Private well owners should have their water tested periodically. The suggested frequency of water testing depends on many factors, including past test results, age of the well, and proximity to sites using hazardous chemicals.

Find answers to frequently asked questions about private wells

Arsenic in private wells

Arsenic is a natural substance that exists in the soil and bedrock in parts of Massachusetts. Commercial uses of arsenic can also contaminate the ground and water. Owners of private wells should have their water tested for arsenic.

The link below will connect you to information on arsenic, health effects of ingesting arsenic, testing private well water, and treating contaminated water.

Frequently asked questions about arsenic in private well water

Additional Resources   for Private well drinking water

Labs certified to test drinking water

MassDEP certifies laboratories that are best equipped to test water samples and provide valid test results. MassDEP highly recommends using a certified laboratory. Your local Board of Health may require you to use a MassDEP certified laboratory.

Find a MassDEP certified laboratory

Finding the right certified laboratory

Laboratories may be certified to only test for certain contaminants. Laboratories may use different testing methods. Some laboratories are private companies or affiliated with private companies that may sell drinking water products. The link below can help you through the process of getting your water tested and choosing a laboratory. 

Frequently asked questions about private drinking water testing

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Lead in drinking water

MassDEP requires your local water department to test tap water in a sample of homes that are likely to have high lead levels. These are usually homes with lead service lines or lead solder. The EPA requires that 90% of homes tested for lead must be below the designated Action Level. If more than 10% of homes in a sample have lead above the Action Level, the water system must take steps to reduce corrosion of lead pipes. 

Public drinking water is tested for lead at the source. Lead contamination often comes from lead water service pipes that connect your home to the water system. MassDEP encourages testing your water for lead, even if your water is from a public source. To find out if your home has a lead service line call your local water department. 

The Massachusetts Water Resources Authority offers extensive information about lead in drinking water, drinking water test results, and reducing lead exposure.

Read about lead in drinking water from the Massachusetts Water Resources Authority

Reduce exposure to lead

Running tap water until it is cold will flush out contaminated water that has been sitting in lead pipes. Using hot water from the tap for cooking or drinking can increase lead levels in water. Boiling water will not reduce lead. 

Learn more about lead in drinking water

Water filters can reduce the amount of lead in drinking water, but not all filter out lead. The U.S. National Sanitation Foundation provides guidelines for buying water filters and information about what they filter.

Learn about safe and effective water filtration systems

Additional Resources   for Lead in drinking water

Boil orders for drinking water

When public water supplies pose a risk to public health, MassDEP issues boil water orders. Boil water orders occur when there is a substance or organism in water that could cause illness or technical water systems issues increased the risk of water-borne illness.

Boiling tap water should significantly reduce the risk of illness from using the water. MassDEP, the Massachusetts Department of Public Health, or Public Water Suppliers should notify you if other precautions are necessary. 

During a boil water order, water should be boiled for:

  • Drinking
  • Brushing teeth
  • Ice cubes
  • Cooking 
  • Any other uses in which water is ingested

Look up Massachusetts boil water orders by town

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Drinking water data and test results

Public water suppliers collect data on the tests of their water. Currently, only a subset of this data is available to the public through the Energy and Environmental Affairs Data Portal.  Additional drinking water data will be available in the future. Energy and Environmental Affairs data on many topics can be found in the data portal, including for drinking water. 

Drinking water data will include:

  • Public water supplier name
  • Town the water was tested in
  • Location the water was tested from
  • Chemical that was tested for
  • Amount of chemical present
  • Maximum allowed chemical level

Your public water supplier is the best resource for learning what is in your drinking water, in many cases. If you cannot find the data you are looking for, you can contact your public water supplier.

Find your local public water supplier's contact information

Color, taste, and odor of drinking water

Unusual color, taste, and odor of drinking water is not always a health hazard. It is important to identify the cause of changes to your drinking water. 

Most changes to color, taste, or odor of drinking water are easily explained. The causes of changes are often due to the water pipes and devices in your home, but can be caused by contamination or public water supply issues.

MassDEP's guide to color, taste, and odor in drinking water will help you find the cause of changes to your drinking water and offers potential solutions. 

Read the guide to color, taste, and odor of drinking water

If problems continue with your drinking water and your water comes from a public water supply, contact your regional MassDEP office.

If problems continue with your drinking water and your water comes from a private well, contact your local board of health.


Public water supplier document search

Use the document search tool to find public water supplier documents, such as:

  • Certificate of Registration
  • Water Quality Report for Transient Non-Community Water Systems (TNC CCR) and Non-Transient Non-Community Water Systems (NTNC CCR)
  • Compliance Monitoring Schedules for Community, Non-Transient Non-Community, and Transient Non-Community Water Systems
  • Lead and Copper Approved Sampling Sites Plan for Community (COM) and Non-Transient Non-Community (NTNC) Systems. Note, Lead and Copper Approved Sampling Sites Plans are intended solely for public water systems' use and are password protected.


Search public water supplier documents

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