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2019 Annual Drinking Water Quality Report

HANSCOM AIR FORCE BASE, Mass. --  The 2019 Annual Drinking Water Quality Report for Massachusetts Water Resource Authority, or MWRA, Lexington, Massachusetts, and Hanscom Air Force Base, Mass., Public Water System Identification, or PWSID, Number 3023002.

This report is an annual summary of the drinking water quality provided by Hanscom Air Force Base, Mass. Under the Consumer Confidence Reporting Rule of the Environmental Protection Agency's Safe Drinking Water Act, or SDWA, community water systems are required to report this water quality information to the consuming public annually.

Presented in this report is information on the source of our drinking water, where it comes from, its chemical composition, how its quality compares to state and federal standards and the health risks associated with any contaminants present. For those interested in an opportunity for public participation in decisions that may affect the quality of the water, please contact the personnel listed below. Meetings take place on a non-routine basis and as needed.

I. Public Water System Information

Address: Hanscom Air Force Base

Contact: Renata N. Welch, 66th Civil Engineering Division; and Tech. Sgt. Andrew R. Bailey, Bioenvironmental Engineering. Telephone: 781-225-6142 and 781-225-6366. Email: renata.welch@us.af.mil and/or andrew.r.dailey.mil@mail.mil.

Water System Improvements:

The Hanscom Air Force Base water system is routinely inspected by the 66th Civil Engineering Division Utilities section (CE); and 66th Medical Squadron Bioenvironmental Engineering (BE). These two organizations inspect the system for its technical, financial and managerial capacity to provide safe drinking water to residents.

II. Drinking Water Source

The water supplied to Hanscom AFB is from the adjacent towns of Lexington and Bedford, Mass. Lexington receives its water from the Massachusetts Water Resource Authority (MWRA). Bedford receives most of its water also from MWRA, as well as a small amount from the Shawsheen Groundwater Treatment Facility.

The MWRA water comes from the Quabbin Reservoir, located about 65 miles west of Boston, and the Wachusett Reservoir, located about 35 miles west of Boston. Water is sent from the Quabbin Reservoir through the Wachusett Reservoir to MetroWest and Greater Boston cities and towns, including Hanscom AFB.

Quabbin and Wachusett watersheds are protected naturally through MWRA and the Massachusetts Department of Conservation and Recreation, or DCR. More than 85 percent of the watersheds are covered in forest and wetlands that help purify water as it flows across the land to the reservoirs. MWRA and DCR control land use and access to the watersheds. DCR patrols watersheds daily and MWRA scientists make sure the watersheds, streams and reservoirs are regularly tested.

III. Drinking Water Treatment

The John J. Carroll Water Treatment Plant in Marlborough, Mass., provides the drinking water for 51 communities, including Greater Boston, the MetroWest areas and three in Central Massachusetts. The plant averages treatment of 275 million gallons of water daily, or up to 405 on a peak day.

Water is treated with ozone as the primary disinfection followed by ultraviolet light as a secondary disinfectant. Ozone provides better disinfection than chlorine alone and reduces formation of disinfection byproducts. UV light damages the DNA of bacteria, viruses and other pathogens making it a strong disinfectant. Furthermore, UV light inactivates chemically resistant parasites such as Cryptosporidium and Giardia. The water chemistry is adjusted for corrosives to minimize the leaching of lead and copper in home plumbing systems. Fluoride is added to promote dental health.

Before water enters the MWRA distribution system, chloramines are added as a secondary disinfectant to provide longer-lasting disinfection as water moves through pipes to consumers. Based on the levels of total chlorine leaving the MWRA facility, Hanscom AFB does not supplement the distribution system with any additional disinfectant. In the event of a water quality emergency, the Hanscom Contingency Response Plan, Annex P will be implemented to provide adequate health and safety measures to water consumers.


Sources of drinking water, both tap water and bottled water, include rivers, lakes, streams, ponds, reservoirs, springs and wells. As water travels over the surface of the land or through the ground, it dissolves naturally occurring minerals, and in some cases, naturally occurring radioactive material. It can pick up substances naturally from the presence of animals or from human activity.

Contaminants that may be present in source water include:

Microbial contaminants: such as viruses and bacteria, which may come from sewage treatment plants, septic systems, agricultural livestock operations or wildlife.

Inorganic contaminants: such as salts and metals, which can be naturally-occurring or result from urban stormwater runoff, industrial or domestic wastewater discharges, oil and gas production, mining or farming.

Pesticides and herbicides: that may come from a variety of sources such as agricultural or urban stormwater runoff, and residential uses.

Organic chemical contaminants: including synthetic and volatile organic chemicals, which are byproducts of industrial processes and petroleum production, and can come from gas stations, urban stormwater runoff and septic systems.

Radioactive contaminants: can be naturally occurring or the result of oil and gas production and mining activities.

In order to ensure that tap water is safe to drink, the U.S. Environmental Protection Agency, or EPA, prescribes regulations that limit the amount of certain contaminants in water provided by public water systems. The Food and Drug Administration, or FDA, regulations establish limits for contaminants in bottled water that must provide the same protection for public health.

All drinking water, including bottled water, may reasonably contain 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 is available by calling the EPA Safe Drinking Water Hotline at 800-426-4791.

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 some infants can be particularly at risk from infections. These people should seek advice about drinking water from their health care providers. EPA/Centers for Disease Control and Prevention guidelines on appropriate means to lessen the risk of infection by Cryptosporidium and other microbial contaminants are available from the Safe Drinking Water Hotline at 800-426-4791.

IV. Important Definitions

Maximum Contaminant Level, or MCL, is the highest level of a contaminant in drinking water. MCLs are set as close to the Maximum Contaminant Level Goals (see below) as feasible using the best available treatment technology.
Maximum Contaminant Level Goal, or MCLG, is the level of a contaminant in drinking water below which there is no known or expected risk to health. MCLGs allow for a margin of safety.
Maximum Residual Disinfectant Level, or MRDL, is the highest level of a disinfectant (chlorine, chloramines, chlorine dioxide) allowed in drinking water. There is convincing evidence that addition of a disinfectant is necessary for control of microbial contaminants.
Maximum Residual Disinfectant Level Goal, or MRDLG, is the level of a drinking water disinfectant (chlorine, chloramines, chlorine dioxide) below which there is no known or expected risk to health. MRDLG's do not reflect the benefits of the use of disinfectants to control microbial contaminants.
Action Level, or AL, is the concentration of a contaminant that, if exceeded, triggers treatment or other requirements that a water system must follow.
90th Percentile means that out of every 10 homes, nine were at or below this level.
Treatment Technique, or TT, is a required process intended to reduce the level of a contaminant in drinking water.
Variances and Exemptions is that state or EPA permission not to meet an MCL or a treatment technique under certain conditions.
Secondary Maximum Contaminant Level, or SMCL, the standards are developed to protect the aesthetic qualities of drinking water and are not health based.

Level 2 Assessment, a detailed study of the water system to identify potential problems and determine (if possible) why an E. coli MCL violation has occurred and/or why total coliform bacteria were found in the water system on multiple occasions.

V. Water Quality testing Results

EPA and state regulations require water quality testing after treatment. MWRA follows, and even goes beyond, federal and state standards with the frequency and sensitivity of tests. The EPA has identified more than 120 contaminants that must be tested in drinking water. A complete list can be found at www.mwra.com.

During 2019, the MWRA reported finding nine EPA identified contaminants, listed in the tables below. None of the contaminant levels detected exceeded the EPA's MCLs.

Links to the full reports for the towns of Lexington and Bedford are at http://www.mwra.com/annual/waterreport/2018results/2018results.htm. Select Lexington’s report under “Fully Supplied Metro Boston/Metro West Communities.” Select Bedford’s report under “Partially Supplied Communities.”

Table 1: MWRA Sampling Results

Hanscom AFB has one interconnection with Bedford that is used to supply the 66th Force Support Squadron's FamCamp. Bedford derives some of its drinking supply from the groundwater wells. However, most of the water is sourced from MWRA and purchased from Lexington. In 2019, the entire system provided 200 million gallons of water. MWRA supplied approximately 97 percent of this water. The Shawsheen Groundwater Treatment Facility supplied the remaining three percent, however, Oct. 24, 2019, Bedford shut down this facility as a drinking source until further notice.

MWRA also tests reservoir water for pathogens such as fecal coliform, bacteria, viruses and the parasites Cryptosporidium and Giardia that can enter the water from animal or human waste. All test results were well within state and federal testing and treatment standards. Cryptosporidium can cause gastrointestinal illness, with symptoms that include diarrhea, nausea and/or stomach cramps. People with severely weakened immune systems --that is, severely immuno-compromised -- are likely to have more severe and more persistent symptoms compared to healthy individuals. 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 at 800-426-4791.

Hanscom AFB provides quality drinking water by maintaining the local distribution system, flushing the system and testing regularly. Along with the routine water evaluations performed by the MWRA, the base's BE office monitors the temperature, chlorine and pH levels when officials collect samples twice monthly at eleven locations on the base and at Fam Camp. A qualified staff member collects samples and delivers them to the MWRA for analysis.

Bacteriological Testing: The drinking water at Hanscom AFB is tested twice a month. Eleven samples taken across Hanscom are tested for Total Coliform. Total Coliform is a non-pathogenic bacteria that is naturally present in the environment. A Total Coliform positive from the lab is an alert to check for E.coli, which is a subgroup of fecal coliform. The MCL for Hanscom is two positive samples a month.

In 2019, eight samples tested positive for total coliform: two each in September, October, November and December as shown in Table 2. No disease causing bacteria were detected.

As a result of positive coliform detections, four Level 2 Assessments were required for the water system to maintain compliance. Four Level 2 Assessments were completed, however, one of the four was performed outside of the regulatory time limits. In addition, base officials were required to take seven corrective actions; only six of these actions were completed.

Lead and Copper: If present, elevated levels of lead can cause serious health problems when present, 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 water is lead-free when it leaves the reservoirs. The pipes that carry the water to communities are made mostly of iron and steel and do not add lead to water. However, local water pipes and home plumbing fixtures containing lead and copper material may affect water quality at the tap. Corrosion or pipes wearing away may also add lead and copper to tap water. When water remains stagnant in the system for a prolonged period of time due to inactivity, flushing the tap for 30-seconds to 2-minutes is recommended before using for drinking or cooking. Those concerned about lead in their water may request Bioenvironmental or the housing office to have water tested. Information on lead in drinking water, testing methods and steps residents can take to minimize exposure to lead is available from the Safe Drinking Water Hotline or at http://www.epa.gov/safewater/lead.

In 2019, testing was conducted at 30 random locations, including schools, child care centers throughout Hanscom AFB and the Fam Camp to determine compliance with established guidelines. The 90th percentile results for both lead and copper were below the EPA established action levels (Table 3). This puts the Hanscom AFB system in compliance with federal regulation requirements. The next lead and copper compliance sampling period is scheduled for September 2022.

Table 3: 2016 Hanscom AFB Lead and Copper Sampling Results

Water samples collected as part of lead screening at the Child Development Center and Youth Center all tested below the lead action level (AL) of 0.015 mg/L. The EPA requires two potable faucets be checked, while the Department of Defense requires all faucets at the CDC and Youth Center be checked. Listed in Table 4 include locations sampled and results detected.

In 2018, water samples collected at the School-Age Program in Building 1999 detected eight samples that exceeded the action level (AL) of 0.015 mg/L for lead. A bottled water program was, and continues to be in effect for building 1999. Following the replacement of piping and faucets in the facility in 2019, officials collected water samples from seven locations at the School-Age building. Officials removed one sink during renovations dropping the number of sampling locations from eight to seven. All locations tested below the lead AL of 0.015 mg/L as summarized in Table 4. A bottled water program is still in effect because the EPA recently adopted a goal to reduce lead levels in schools and Childcare Centers to either below 1 ppb (0.001 mg/l), or non-detectable, which has not been met at all locations sampled.

Table 4: 2014 Hanscom AFB Child Development Center and Youth Center Sampling Results


Does Hanscom Air Force Base drinking water meet current health standards?

Hanscom AFB CE and BE are committed to providing you with the best water quality available through regular monitoring and corrective actions. However, some contaminants that were tested last year did not meet all applicable health standards regulated by the state and federal government. Due to contaminant violations of Total Coliform during the period of September through December 2019, base officials took the following corrective actions. 

                • Additional samples were taken

              • The affected system segments were flushed daily

              • The tap in one affected building was replaced

The health effect statement for this contaminant is listed below. In addition, Hanscom AFB has contingency plans in place to both notify and protect base personnel in the event monitoring results indicate a potential concern. 

Hanscom AFB received one Notice of Noncompliance Nov. 8, 2019, for a failure to perform a Level 2 Assessment associated with Total Coliform detections in October 2019 within regulatory time limits. Officials were still conducting continued sampling and flushing of the system at the affected buildings from the September 2019 Total Coliform detections and associated Level 2 Assessment, so there was no health risk associated with this Notice of Noncompliance. However, this was a ‘Tier 2’ violation requiring Public Notice. Base officials distributed the Public Notice by email on Dec. 13, 2019, in addition to publishing in the Hansconian on Dec. 5, 2019, and on the internal CAC-enabled HanscomNet  Dec. 13, 2019.

Health Effects Statements

Total Coliform: Coliforms are bacteria that are naturally present in the environment and used as an indicator that other potentially harmful bacteria may be present. Officials found coliforms in more samples than allowed and this was a warning of potential problems.


Frequently asked questions:

Q. How would I know about a problem with the water supply?

A. Bioenvironmental Engineering and Water Utilities regularly test and inspect the water supply and the distribution system. If a problem was found, all affected people would be notified through leaflets, email and the Hansconian, the base newspaper.

Q. My water tastes and smells funny. Is it safe to drink?

A. According to MWRA, you can safely drink and cook with the water. Algae can cause water to have a "funny" smell and odor. Algae are normal, harmless plants that appear in the reservoirs at certain times of the year. On occasion, customers may also taste or smell the low levels of chlorine compounds added to disinfect the water. Fill a jug with tap water and put it the refrigerator to get rid of the taste and odor.

Q. My water is cloudy sometimes but then clears up. Can I drink it?

A. You can safely drink and cook with the water. Water travels under pressure throughout the system. Occasionally, air can become trapped in the water in tiny bubbles causing water to look cloudy. This is only temporary and the water clears up in a short time.

Q. My water is discolored. Can I drink it?

A. According to MWRA, you can safely drink and cook with the water. Old iron pipes in buildings can cause a red, brown or yellow color in the water. A yellow color is from iron that is absorbed by water that has been sitting in pipes for a long time. Small specks of iron in the water cause a red or brown color. These specks of iron can enter the water if there is a quick change in water speed or direction in your local pipes. Such changes can result from valve repair, flushing the system, or the testing and use of fire hydrants.

For more information or concerns about anything contained in this report, contact any of the numbers listed below. Hanscom does not hold regularly scheduled board meetings for public participation in decisions that may affect the quality of the water.

Bioenvironmental Engineering: 781-225-6366

Massachusetts Water Resource Authority: 617-242-5323

EPA Safe Drinking Water Hotline: 800-426-4791

Hanscom AFB Public Affairs Office: 781-225-1685

Bedford Department of Public Works: 781-275-7605

Additional information can be obtained by viewing the following websites: