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MWRA's Drinking Water Test Results for 2012 Published June, 2013
Massachusetts Water Resources Authority

HTML Version- Metro Communities

Below are MWRA's 2011 Drinking Water Test Results for MetroWest and Metro Boston communities that receive all of their drinking water from MWRA.

Results for partially-supplied communities and Chicopee, South Hadley and Wilbraham are available for download.

This report includes the results of those tests for 2011. This report is required under the federal Safe Drinking Water Act Public Law 104-12, Section 1414 (C), PWS ID #6000000.

Water Test Results
cover of 2011 annual waqter quality report
Back to MWRA 2012 Annual Drinking Water Test Results Main Page
Download a PDF of this report
(Metro version)
en Español 2012 (PDF)
Annual Water Quality Report Archive
All MWRA Water Quality Tests
Table of Contents
Message from MWRA Executive Director Fred Laskey
Where your water comes from
Map of the MWRA water system
How your water is treated
MWRA’s improvements to the water supply
Test results
Information about lead
Important Information from EPA and DEP
Special notice for the immuno-compromised
Facts about sodium
Information about cross connections
Water conservation
Where to go for more information
Contact us
Additional information from your city or town water department

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Message from MWRA Executive Director Fred Laskey

Dear Customer,

I am pleased to share with you the results of our annual water quality testing. MWRA takes hundreds of thousands of tests each year, and for 2012, we again met every federal and state drinking water standard.

System-wide, we have been below the Lead Action Level for the past nine years. Please read the additional information from your city or town water department for more information on your local water system.

MWRA continues to work to make the water system even better. Construction of a new covered storage tank in Stoneham and improved ultraviolet disinfection facilities at the Carroll Treatment Plant in Marlborough are currently underway. And, with the completion this spring of the rehabilitation of the Hultman Aqueduct, we now have full redundancy from the treatment plant into the distribution system for the first time. This is a vast improvement to the water system and will ensure the delivery of water in the event of a major break, like the one that occurred in May 2010.

This report describes where your water comes from, how it is treated and delivered, and the steps we take to ensure its quality. Please take a moment to read it so that you can share our confidence in your drinking water.

In 2012, MWRA again received the Drinking Water Excellence Award from the Massachusetts Department of Environmental Protection. Some of the best drinking water in the country is delivered straight to your home. When you have a choice, we hope you drink locally!

Frederick A. Laskey
Executive Director

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Where Does Your Water Come From?

Drink Local
and Be Green!
Tap water is delivered straight to your home without trucking or plastic waste. Bottled water produces over 10,000 times the amount of greenhouse gases compared to tap water. One bottle of water is the equivalent of a month’s supply of tap water. That is because our water is local, and because almost half of our energy needs are met with green power including hydro-energy, wind turbines, and solar panels. Drink local! Drink tap water! Be green!

Your water comes from the Quabbin Reservoir, about 65 miles west of Boston, and the Wachusett Reservoir, about 35 miles west of Boston. These 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 2012.

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, viruses, and fertilizers - 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

mwra water map


How Your Water is Treated

Your Water System
From the Reservoir to Your Home

What is Ozone?
Ozone consists of 3 atoms of oxygen. It is created by applying an electrical current to pure oxygen in a specially designed chamber. Ozone provides better disinfection than chlorine alone, especially against Cryptosporidum and other hard to kill germs. It also reduces the amount of potentially harmful disinfection byproducts.

Your tap water is treated at the John J. Carroll Water Treatment Plant in Marlborough. The first treatment step is disinfection of reservoir water. MWRA’s licensed treatment operators carefully add measured doses of ozone gas bubbles – produced from pure oxygen – to the water to kill any pathogens (germs) that may be present in the water. Fluoride is then added to promote dental health. Next, the water chemistry is adjusted to reduce corrosion of lead and copper from home plumbing. Last, we add mono-chloramine, a mild and long-lasting disinfectant combining chlorine and ammonia, which protects the water while it is in the local pipelines.

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MWRA’s Improvements to the Water Supply

Since 1985, MWRA and our community partners have made improvements to the entire water system - from the watersheds to the local pipelines. In 2012, MWRA continued construction of a new covered water storage tank in Stoneham and the addition of ultraviolet (UV) disinfection facilities at the treatment plant in Marlborough. Of note this year is the completion of the rehabilitation of the Hultman Aqueduct, ensuring full redundancy from the treatment plant into the distribution system.

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Testing Your Water Every Step of the Way:
2012 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. There are two standards for turbidity: all water must be below 5 NTU (Nephelometric Turbidity Units), and only can be above 1 NTU if it does not interfere with effective disinfection. MWRA met both of these standards. Typical levels at the Wachusett Reservoir are 0.4 NTU. In 2012, turbidity was always below both the 5.0 and 1.0 NTU standards, with the highest level at 0.7 NTU. MWRA also tests reservoir water for pathogens such as fecal coliform, bacteria, and the parasites Cryptosporidum and Giardia. They can enter the water from animal or 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 Details about 2012 test results are in the table below. The bottom line is that the water quality is excellent.

Test Results After Treatment
Details about 2012 are listed. The bottom line is that the water quality is excellent.
(We found) Detected
Range of
How it gets in the water
Common mineral in nature
Water disinfectant
Additive for dental health
Nitrate ^
Atmospheric deposition
Nitrite ^
Byproduct of water disinfection
Byproduct of water disinfection


Byproduct of water disinfection
Byproduct of water disinfection
Total Coliform
0.5% (Aug)


Naturallly present in the environment

KEY: MCL=Maximum Contaminant Level. The highest level of a contaminant allowed in water. MCLs are set as close to the MCLGs as feasible using the best available technology.
MCLG=Maximum Contaminant Level Goal. The level of contaminant in drinking water below which there is no known or expected risk to health. MCLGs allow for a margin of safety. MRDL=Maximum Residual Disinfectant Level. The highest level of a disinfectant allowed in drinking water. There is convincing evidence that addition of a disinfectant is necessary for control of microbial contaminants. MRDLG=Maximum Residual Disinfectant Level Goal. The level of a drinking water disinfectant below which there is no known or expected health risk. MRDLGs do not reflect the benefits of the use of disinfectants to control microbial contamination. ppm=parts per million ppb=parts per billion ns=no standard ^As required by DEP, the maximum result is reported for nitrate and nitrite, not the average.


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 2012. If your community found any total coliform in its local pipes, the results will be listed in the additional information from your city or town water department.


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 substances. To better understand the drinking water, MWRA has also voluntarily been testing for Cryptosporidium and Giardia prior to treatment.

Measurement Units
oocysts per 100L
cysts per 100L
Hexavalent Chromium
parts per billion
parts per trillion

Key: *The result is from 2009. The DEP guidance value is 10 ppt.
^The result is from 2011.

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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. MWRA and local pipes that carry the water to your community are made mostly of iron and steel and do not add lead to the water. However, lead can get into tap water through pipes in your home, your lead service line, lead solder used in plumbing, and some brass fixtures. Corrosion or wearing away of lead-based materials can add lead to tap water, especially if water sits for a long time in the pipes before it is used.

In 1996, MWRA began adding sodium carbonate and carbon dioxide to adjust the water's pH and buffering capacity. This change has made the water less corrosive, thereby reducing the leaching of lead into drinking water. Lead levels found in sample tests of tap water have dropped by almost 90 percent since this treatment change.

MWRA Meets Lead Standards in 2012

Under EPA rules, each year MWRA and your local water department must 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 rule requires that 9 out of 10, or 90%, of the sampled homes must have lead levels below the Action Level of 15 parts per billion (ppb). Test results have met the EPA standard for 9 years straight. Results for the 450 samples taken in September 2012 are shown in the table. 9 out of 10 houses were below 7.7 ppb, which is below the Action Level of 15 ppb. Only two communities had more than one home test above the Action Level for lead. If you live in either of these communities, your community's letter will provide you with more information.

September 2012 Lead and Copper Results
Lead (ppb)
90% Value
90% Value
(Target) Action Level

(Ideal Goal) MCLG

# Homes above AL/# Homes Tested
Copper (ppm)
ppb = parts per billion. ppm = parts per million. AL=Action Level-The concentration of a contaminant which, if exceeded, triggers treatment or other requirements which a water system must follow. MCLG=Maximum Contaminant Level Goal The level of contaminant in drinking water below which there is no known or expected risk to health. MCLGs allow for a margin of safety.

90th Percentile Lead Levels for
MWRA Communities: 1992-2012 (ppb)
9th percentile graphic
larger image

What can I do to reduce exposure to lead in drinking water?

  • Run the tap until after the water feels cold. To save water, fill a pitcher with fresh water and place in the refrigerator for future use.
  • Never use hot water from the faucet for drinking or cooking, especially when making baby formula or other food for infants.
  • Ask your local water department if there are lead service lines leading to your home.
  • Check your plumbing fixtures to see if they are lead-free. Read the labels closely.
  • Test your tap water. Call the MWRA Drinking Water Hotline (617-242-5323) or visit our website for more tips and a list of DEP certified labs that can test your water.
  • Be careful of places you may find lead in or near your home. Paint, soil, dust and some pottery may contain lead.
  • Call the Department of Public Health at 1-800-532-9571 or EPA at 1-800-424 LEAD for information.

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

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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 for 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).

Tap Water - the Smart Choice!
Although tap water and
bottled water have to meet the same standards, tap water must meet the more intensive EPA testing requirements. Yet, tap water costs less than a penny per gallon delivered straight to your home, while bottled water can cost between $1 to $8 a gallon.

Contaminants in Bottled Water and Tap 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. 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 34.7 mg/L (about 9 mg per 8 oz. glass). This would be considered VERY LOW SODIUM by the Food and Drug Administration.

Information about Cross Connections

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

Water Conservation

Wasting water can add up quickly. On average, each person uses about 65 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

Web Sites and Telephone Numbers
Mass. Department of Conservation and Recreation
Source Water Assessment and Protection Reports
Information on Water Conservation

Public Meetings
MWRA Advisory Board
Water Supply Citizens Advisory Committee


Contact Us

If you have questions or comments about this report, please contact us. Call (617) 242-5323, e-mail, 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.

Fully Supplied Communities
These communities receive all of their drinking water from MWRA.
The water is treated at the Carroll Water Treatment Plant
and transmitted via the MetroWest Tunnel.
Lexington Nahant Somerville
Lynnfield W.D. Newton Southborough
Boston Norwood Stoneham
Brookline Quincy Swampscott
Chelsea Reading Waltham
Everett Revere Watertown
Framingham Saugus Weston


Partially Supplied Communities
These communities receive some of their drinking water from MWRA.
The MWRA water is treated at the Carroll Water Treatment Plant
and transmitted via the MetroWest Tunnel.
Canton Northborough Winchester
Residents of Peabody, Stoughton and Wellesley: please contact your local water department for your report.

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Updated June 6, 2013