Where Does Your Water Come From?

Why Your Water Tastes Great -- High Quality Source Water

Your water comes from the Quabbin Reservoir, about 65 miles west of Boston, and the Wachusett Reservoir, about 35 miles west of Boston. These pristine reservoirs supply wholesale water to local water departments in 51 communities. The two reservoirs combined supplied about 200 million gallons a day of high quality water to consumers in 2014.

The Quabbin and Wachusett watersheds are naturally protected with over 85% of the watersheds covered in forest and wetlands. To ensure safety, the streams and reservoirs are tested often and patrolled daily by the Department of Conservation and Recreation (DCR).

Rain and snow falling on the watersheds - protected land around the reservoirs - turn into streams that flow to the reservoirs. This water comes in contact with soil, rock, plants, and other material as it follows its natural path to the reservoirs. While this process helps to clean the water, it can also dissolve and carry very small amounts of material into the reservoir.

Minerals from soil and rock do not typically cause problems in the water. But, water can also transport contaminants from human and animal activity. These can include bacteria and viruses - some of which can cause illness. The test data in this report show that these contaminants are not a problem in your reservoirs' watersheds.

The Department of Environmental Protection (DEP) has prepared a Source Water Assessment Program report for the Quabbin and Wachusett Reservoirs. The DEP report commends DCR and MWRA on the existing source protection plans, and states that our “watershed protection programs are very successful and greatly reduce the actual risk of contamination.” MWRA follows the report recommendations to maintain the pristine watershed areas.

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Map of the MWRA Water System

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Testing Your Water Every Step of the Way:
2014 Test Results

Test results show few contaminants are found in the reservoir water. The few that are found are in very small amounts, well below EPA's standards. Turbidity (or cloudiness of the water) is one measure of overall water quality. All water must be below 5 NTU (Nephelometric Turbidity Units), and water can only be above 1 NTU if it does not interfere with effective disinfection. In 2014, turbidity was always below both the 5.0 and 1.0 NTU standards, with the highest level at 0.62 NTU. Typical levels at the Wachusett Reservoir are 0.3 NTU.

MWRA also tests reservoir water for pathogens such as fecal coliform, bacteria, viruses, and the parasites Cryptosporidum and Giardia. They can enter the water from animal or human waste. All test results were well within state and federal testing and treatment standards.

Test Results - After Treatment

EPA and state regulations require many water quality tests after treatment to check the water you are drinking. MWRA conducts hundreds of thousands of tests per year on over 120 contaminants (a complete list is available on www.mwra.com). Details about 2014 test results are in the table below. The bottom line is the water quality is excellent.

Tests in Community Pipes

MWRA and local water departments test 300 to 500 water samples each week for total coliform bacteria. Total coliform bacteria can come from the intestines of warm-blooded animals, or can be found in soil, plants, or other places. Most of the time, they are not harmful. However, their presence could signal that harmful bacteria from fecal waste may be there as well. The EPA requires that no more than 5% of the samples in a month may be positive. If a water sample does test positive, we run more specific tests for E.coli, which is a bacteria found in human and animal fecal waste and may cause illness. No E.coli was found in any MWRA community in 2014. If your community found any total coliform, it will be listed within your community's letter.

Ongoing Research for New Regulations

MWRA has been working with EPA and other researchers to define new national drinking water standards by testing for unregulated contaminants. To read more about these regulations, and to see a listing of what was found in MWRA water, please visit www.mwra.com/UCMR/2014.html.

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Why Your Water Tastes Great -- Water Treatment

One of the reasons that the Boston area water tastes so good is that MWRA has state-of-the-art treatment at the John J. Carroll Water Treatment Plant in Marlborough.

Since 2005, your water has been treated with ozone - produced by applying an electrical current to pure oxygen. Ozone has ensured strong protection against microbes and viruses, improved water clarity, and makes the water taste better.

Starting in 2014, we also added ultraviolet (UV) disinfection, further improving the quality of the water. UV light is essentially a more potent form of the natural disinfection from sunlight, and ensures that any pathogens potentially in our reservoirs are rendered harmless.

In addition, the water chemistry is adjusted to reduce corrosion of lead and copper from
home plumbing. Fluoride is added to promote dental health, and in April 2015 the dose was
lowered to 0.7 ppm based on CDC and EPA recommendations. Last, we add monchloramine, a mild and long lasting disinfectant to protect the water as it travels to your home.

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Investments in Your Water System

Preparing Dams for Climate Change
Since 2006, MWRA has spent over $21 million on dam safety projects. All MWRA dams, dikes, spillways and appurtenances are inspected routinely by licensed dam safety engineers and are in good condition.

Protecting Reservoirs While Providing Open Space
The best way to deliver clean, safe water is to start with high quality source water. Since 1985, $134.5 million has been invested in land preservation around the Quabbin, Ware and Wachusett watersheds.

Monitoring Water Quality in Real Time
Your water is monitored by a state-of-the-art system in real time – 24 hours a day, seven days a week – to make sure it is free of contaminants. This allows MWRA to respond to changes in water quality almost immediately.

Taking Advantage of Gravity
MWRA operates three hydroelectric generators that capture the energy of the water as it flows east providing $1.5 million in renewable energy annually.

Covered Storage Keeps Water Safe and Clean
MWRA has constructed a network of covered storage tanks across the service area that keep your water protected from the treatment plant to your tap. The Spot Pond Tank in Stoneham will open later this year.

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Facts About Lead

What You Need to Know about Lead in Tap Water

MWRA water is lead-free when it leaves the reservoirs, and MWRA and local pipes do not add lead to the water. However, lead can get into water through household plumbing including some service lines (the pipe from the street to your house). Check with your local water department if you have a lead service line. If you do, you should replace it.

Under EPA rules, each year your local water department must test water in homes that are likely to have high lead levels. The requirement is that 90% of the sampled homes must have lead levels below the Lead Action Level of 15 ppb. Since corrosion control treatment began in 1996, lead levels in tested homes have dropped over 90%, and 19 straight sampling rounds have been below the EPA Action Level. For tips on how to reduce your possible exposure to lead, visit www.mwra.com/lead.html.

Important Information from EPA about Lead

If present, elevated levels of lead can cause serious health problems, especially for pregnant women and young children. Lead in drinking water is primarily from materials and components associated with service lines and home plumbing. MWRA is responsible for providing high quality drinking water, but cannot control the variety of materials used in plumbing components. If your water has been sitting for several hours, you can minimize the potential for lead exposure by flushing your tap for 30 seconds to 2 minutes before using water for drinking or cooking.

If you are concerned about lead in your water, you may wish to have your water tested. Information on lead in drinking water, testing methods, and steps you can take to minimize exposure is available from the Safe Drinking Water Hotline at 1-800-426-4791 or www.epa.gov/safewater/lead, or MWRA at 617-242-5353 or www.mwra.com/lead.html.

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Important Information from EPA and DEP

Drinking Water and People with Weakened Immune Systems

Some people may be more vulnerable to contaminants in drinking water than the general population. Immuno-compromised persons such as persons with cancer undergoing chemotherapy, persons who have undergone organ transplants, people with HIV/AIDS or other immune system disorders, some elderly, and infants can be particularly at risk from infections. These people should seek advice about drinking water from their health care providers. EPA/CDC guidelines on appropriate means to lessen the risk of infection by Cryptosporidium and other microbial contaminants are available from the EPA's Safe Drinking Water Hotline (1-800-426-4791).

Contaminants in Bottled Water

Drinking water, including bottled water, may reasonably be expected to contain at least small amounts of some contaminants. The presence of contaminants does not necessarily indicate that water poses a health risk. More information about contaminants and potential health effects can be obtained by calling the EPA’s Safe Drinking Water Hotline (1-800-426-4791) or MWRA. In order to ensure that tap water is safe to drink, the Massachusetts DEP and EPA prescribe regulations which limit the amount of certain contaminants in water provided by public water systems. The Food and Drug Administration (FDA) and the Massachusetts Department of Public Health regulations establish limits for contaminants in bottled water which must provide the same protection for public health.

Facts About Sodium

Sodium in water contributes only a small fraction of a person’s overall sodium intake (less than 10%). MWRA tests for sodium monthly and the highest level found was 34.8 mg/L (about 9 mg per 8 0z. glass). This would be considered Very Low Sodium by the Food and Drug Administration.

Information about Cross Connections

The Massachusetts DEP recommends the installation of backflow prevention devices for inside and outside hose connections to help protect the water in your home, as well as the drinking water system in your town. For more information on cross connections, please call 617-242-5323 or visit www.mwra.com/crosscon.html.

Water Conservation

Wasting water can add up quickly. On average, each person in the MWRA region uses about 60 gallons of water each day. More efficient water use can reduce the impact on the water supply and on your wallet. For ways to make your home and your habits more water efficient, contact the MWRA at 617-242-SAVE or visit our web site for tips on saving water indoors and in your backyard.

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Where to Go for More Information

Contact Us

If you have questions or comments about this report, please contact us. Call (617) 242-5323, e-mail joshua.das@mwra.com, or write to: MWRA, Charlestown Navy Yard, Building 39, Boston, MA 02129.

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Your Community Letter:
Additional Information from Your City or Town Water Department

Read your community letter (PDF) for important information about your water from your city or town water department.

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PDF files on this site require Adobe Acrobat Reader® (Free download.)

Updated May 28, 2015