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Additional Water Quality Data
Massachusetts Water Resources Authority


In addition to conducting hundreds of thousands of water quality analyses of regulated contaminants for compliance monitoring and treatment process control, MWRA collects many other samples to understand more about our water, to track how the system is working and changing over time, and to help researchers and EPA regulators determine if new water quality standards are needed.

MWRA publishes an annual water quality report, focused primarilty on regulated water quality parameters and a more detailed monthly report. More information on MWRA's key performance measures for water quality, maintenance, and financial management can be found here. Additionally to all the data regularly published in those reports, MWRA believes that our users should have access to the water quality data we collect on a periodic basis for other purposes.

If you have questions or would like more information about lead in drinking water, please call our Water Quality Hotline: 617-242-5323, or email Beverly Anderson, Project Manager, Public Health.

PFAS (Per- and Polyfluoroalkyl Substances) in MWRA Drinking Water

You might have seen recent news reports about per- and polyfluoroalkyl substances (together abbreviated as PFAS). These are a class of human-made chemicals typically associated with manufacturing of non-stick coatings, water-proofing and stain-proofing treatments. They have also been associated with certain fire-fighting foams.

The Massachusetts Department of Environmental Protection (MassDEP) set a standard of 20 parts per trillion on October 2, 2020 for the sum of these six PFAS compounds (called PFAS6):

  • Perfluorooctanoic acid (PFOA)
  • Perfluorooctanesulfonic acid (PFOS)
  • Perfluorononanoic acid (PFNA)
  • Perfluorohexanesulfonic acid (PFHxS)
  • Perfluoroheptanoic acid (PFHpA)
  • Perfluorodecanoic acid (PFDA)

While the new regulation’s testing requirements did not kick in until 2021, MWRA tested for the six regulated PFAS as well as a dozen other PFAS compounds, using extremely sensitive testing methods in 2019. MWRA began quarterly testing as required by the MassDEP regulation in January 2021, found here.

As expected given MWRA’s well-protected watersheds and reservoirs, in all testing rounds, no more than trace amounts were detected; the sum of the six regulated PFAS compounds was zero, below the new MassDEP standard of 20 ng/l.

MWRA PFAS Test Results Page

If you live in a partially supplied MWRA water community, your local water department may have tested for PFAS. Results for testing done through MWRA's laboratory are here. For additional information, please contact your local water department.

These compounds are persistent in the environment and have been used for decades in a number of everyday products.

MWRA will continue to perform testing and closely monitor developments in the science around this issue.

MWRA tests the water supply each year for over 120 contaminants to ensure the water supplied is of the highest quality. For more information about PFAS and all other drinking water tests or if you have questions about water quality, please visit MWRA's water testing page, which includes all of our annual and monthly test results, or contact us at 617-242-5323.

Cryptosporidium and Giardia Information

Information found here

Research for New Regulations: Unregulated Contaminant Monitoring Rule

The US Environmental Protection Agency (EPA) periodically requires water systems across the country to conduct monitoring for substances that may be present in drinking water to help understand their national occurrence as part of the process of deciding whether to regulate them.  Under the Safe Drinking Water Act Amendments, EPA established the Unregulated Contaminant Monitoring Rule and is required once every five years to develop a list of up to 30 new contaminants that must be monitored duringa three year period by public water systems that meet the criteria for sampling.  This monitoring is used by EPA to understand the frequency and level of occurrence of unregulated contaminants in the nation’s public water systems (PWSs).

EPA will collect and analyze data for all three years and from systems all across the country to develop an understanding of the occurrence, level and distribution of these substances in drinking water. That data, along with information on potential halth effects and water treatment effectiveness will be used by EPA to determine if any new regulations are needed.

Information found here

Pharmaceuticals and Personal Care Products

Information found here

Pesticides and Herbicides

Information found here

Secondary Contaminants

“Secondary contaminants” include substances that are not health related, but may cause aesthetic, cosmetic, or technical effects in drinking water. Aesthetic effects cause unfavorable tastes and odors, while cosmetic effects cause visual changes which do not damage the body, but are still undesirable. Technical effects cause damage to water equipment or reduced effectiveness of treatment for other contaminants. These contaminants can cause changes in water cloudiness, taste, odor, color, or skin and tooth discoloration at higher levels.

Secondary Maximum Contaminant Levels (SMCLs) are guideline values determined by EPA and MassDEP. They provide non-enforceable limits for public water systems for the management of drinking water, but are not considered a risk to human health at the level of the SMCL. MWRA monitors for these substances on a monthly or quarterly basis. 

The tables below provide a summary of 2022 data. For current data on secondary contaminants in MWRA water, see the MWRA monthly water quality reports at: www.mwra.com/watertesting/watertestlist.html.

For more information on secondary contaminants, go to the EPA's Secondary Drinking Water Standards: Guidance for Nuisance Chemicals or the Massachusetts Drinking Water Standards and Guidelines

In the tables below, CVA is Chicopee Valley Aqueduct communities and Metro Boston is all Metro Boston and Metro West communities serviced by the Carroll Water Treatment Plant. See www.mwra.com/02org/html/whatis.htm for a list of which communities are served by each system. Values are for finished water after treatment unless otherwise indicated.

ND stands for “not detectable” in MWRA water ug/L is the equivalent of parts per billion and mg/L equals parts per million.

Aluminum

 

Units

Average

Range

Metro Boston

ug/L

2.97

ND -19.1

CVA

ug/L

ND

ND

Aluminum is a naturally occurring metal that enters into our water system from rocks and soil. MWRA does not use any aluminum containing treatment chemicals.  Elevated aluminum metals can cause water to turn a greyish color.  The SMCL for aluminum is 200 ug/L. MWRA aluminum levels are well below the MassDEP guidelines.


pH

 

Units

Average

Range

Metro Boston

S.U.

9.6

9.3 – 9.8

CVA

S.U.

7.2

6.8 – 7.6

pH is a measurement of the acidity of a substance. Levels below 7 represent acidity and levels above 7 represent alkalinity. At a lower pH, water will corrode metals such as lead, allowing them to leach into the water. The pH of source water can be changed by local runoff and leaching of natural deposits.  The pH of treated water is altered by treatment processes to manage water quality. Depending on the pH, water can take on a different taste. Low pH may produce a bitter metallic taste and a high pH may produce a slippery feel or a soda like taste. The data in the table represent treated water within the distribution system.  The MWRA adjusts the pH of Metro Boston drinking water to a pH of 9.0 to 9.5 within the distribution system to prevent corrosion and reduce the release of lead from service lines and home plumbing.  While the pH is above the aesthetic guideline of 6.5 to 8.5, the values are necessary for the protection of public health.

MWRA MetroBoston pH levels are those required to meet MassDEP requirements under the Lead and Copper Rule for optimum corrosion control of lead and copper. The values reported for the CVA system are for water delivered to each community. Each CVA community treats the water to reduce corrosion, and may have different pH values.


Chloride

 

Units

Average

Range

Metro Boston

mg/L

30.8

23.1 – 40.0

CVA

mg/L

12.99

8.9 – 24.6

Chloride can enter drinking water from natural minerals or deposits or the use of sodium chloride (NaCl) for road deicing. At elevated levels, chloride can cause water to have a salty taste. The SMCL for chloride is 250 mg/L. MWRA chloride levels are well below the MassDEP guidelines.


Color

 

Units

Average

Range

Metro Boston

C.U.

6.3

5 - 7

CVA

C.U.

4.8

4 - 6

Color is a coloration or tint found in drinking water that can be caused by a variety of metals and compounds that may be present in the water. The color of the water can be used to generally determine the compound in the water. Color change occurs when dissolved or suspended minerals enter into the drinking water.  Elevated copper levels may cause blue-green color, while aluminum will cause water to take on a grey hue. The SMCL is 15 C.U. (Color Units). MWRA color levels are well below the MassDEP guidelines.


Copper

 

Units

Average

Range

Metro Boston

ug/L

55

0-258

CVA

ug/L

62

8 – 610

Copper is a metal that enters into drinking water due to corrosion from domestic pipes or natural deposits. At high concentrations, the metal can create a metallic taste in drinking water and color the water a blue-green. Copper salts may infrequently be used to control algal blooms. The SMCL of copper is 1000 ug/L and the health based Action Level is 1300 ug/L. The data in the table represent treated water within the distribution system for fully supplied communities. MWRA and CVA community corrosion control treatment reduces the amount of copper corrosion from household plumbing.  MWRA copper levels are well below the MassDEP guidelines.


Fluoride

 

Units

Average

Range

Metro Boston

mg/L

0.68

0.39 - 0.83

CVA

mg/L

ND

ND

Fluoride is a naturally occurring mineral in the environment that can leach into drinking water from natural deposits. Fluoride is also added at the Carroll Water Treatment Plant to improve dental health and to prevent against cavities at the CDC recommended level of 0.7 mg/L. None of the CVA communities fluoridate their water.  Fluoride has an SMCL of 2.0 mg/L for aesthetic concerns and an MCL of 4.0 mg/L for health concerns. MWRA fluoride levels are below the MassDEP guidelines.


Iron

 

Units

Average

Range

Metro Boston

ug/L

50.3

16.8 – 197

CVA

ug/L

12.8

7.3 – 22.6

Iron is a metal that naturally occurs in the environment and enters drinking water through rocks and soil deposits. Iron can also be released from older unlined cast iron water mains. The metal may cause drinking water to take on a rusty red or orange color that has a metallic taste. The SMCL for iron is 300 ug/L. MWRA iron levels are below the MassDEP guidelines. However, flow disruption in local water systems from firefighting or main breaks can cause temporary increases in iron levels. MetroBoston values represent distribution system; CVA values represent water delivered to the communities.


Manganese

 

Units

Average

Range

Metro Boston

ug/L

7.1

3.7 - 14.4

CVA

ug/L

2.98

1.6 – 4.4

Manganese is a metal that can leach out of manganese deposits in natural sources into water. Manganese may cause water to have a black or brown color, and a metallic taste. Manganese has an SMCL of 50 ug/L. Massachusetts also has a health related guidance value of 300 ug/L. MWRA manganese levels are below both aesthetic and health-related MassDEP guidelines.


Silver

 

Units

Average

Range

Metro Boston

ug/L

ND

ND

CVA

ug/L

ND

ND

Silver is a metal that occurs naturally in the environment. The SMCL for silver is 100 ug/L. At higher levels, silver may cause skin or eye discoloration. MWRA typically does not detect any silver.


Sulfate

 

Units

Average

Range

Metro Boston

mg/L

6.3

4.9 – 7.8

CVA

mg/L

4.1

3.6 – 5.3

Sulfate is a mineral that can enter drinking water from rocks and soil and from the decay of animal or plant matter in the water source. At elevated levels sulfate can cause drinking water to have a salty taste or a rotten egg smell. The SMCL for sulfate is 250 mg/L. MWRA sulfate levels are well below the MassDEP guidelines.


Total Dissolved Solids (TDS)

 

Units

Average

Range

Metro Boston

mg/L

113.5

106 - 118

CVA

mg/L

40.3

34 - 47

Total dissolved solids (TDS) are substances that may enter drinking water sources from runoff and leaching of natural deposits. The addition of treatment chemicals can also increase TDS levels. TDS may include minerals, salts, dissolved metals, and organic matter.  At high levels, TDS can cause water hardness and may cause water to have a salty taste.  The water may also be colored or stained. Dissolved solids are not known to pose health risks. The SMCL for TDS is 500 mg/L. MWRA TDS levels are well below MassDEP guidelines.


Hardness

 

Units

Average

Range

Metro Boston

mg/L

15.1

13.1 - 16.3

CVA

mg/L

7.3

6.9 - 7.6

Water’s “hardness” and “softness” is due to its concentration of minerals—primarily calcium and magnesium. Hardness can be impacted by TDS in water. The lower the mineral concentration, the softer the water is. Hardness affects the efficiency of soaps and laundry detergent when cleaning. MWRA water is soft. Less soap and shampoo are needed for good lathering, and less dishwashing detergent should be used. Hard water would have a value above 75 mg/L. 
Hardness can also be expressed in terms of grains per gallon. 17.1 mg/l is the equivalent of 1 grain per gallon.  MetroBoston water typically has about 1 grain per gallon of hardness, while CVA has closer to ½ grain per gallon.


Zinc

 

Units

Average

Range

Metro Boston

ug/L

ND

ND - ND

CVA

ug/L

2.9

2.3 – 3.9

Zinc is a metal that enters drinking water through natural deposit leaching and pipe corrosion. It can also be increased by the use of zinc containing treatment chemicals. The metal can cause water to take on a metallic taste. The SMCL for zinc is 5000 ug/L. MWRA does not use any zinc containing treatment chemicals. MWRA zinc levels are well below the MassDEP guidelines.

Updated July 7, 2023

 
Historic Withdrawls Reservoir Levels