The MDC prepares a Water Quality Report annually which provides a summary of the past year’s water quality and includes information on how the MDC collects, treats and delivers high quality drinking water. The MDC’s state licensed Water Analysis Laboratory, located at the Reservoir 6 water treatment plant in Bloomfield, conducts more than 140,000 physical, chemical and bacteriological tests annually. These tests search for over 130 potential water contaminants at the MDC’s reservoirs, treatment plants and the 47 state approved sampling sites throughout the 12 town service area. These tests and others conducted at various consulting laboratories ensure that the potable water supplied by the MDC meets all State of Connecticut Public Health Code and Federal Environmental Protection Agency standards for water quality. The MDC distributes an average of 45 million gallons of water per day to a population of approximately 400,000.

For questions about your water quality, contact the MDC Laboratory at:
(860) 278-7850 ext.3901.

2023 Water Quality Report / 2023 Water Quality Report (Spanish)
2022 Water Quality Report / 2022 Water Quality Report (Spanish)
2021 Water Quality Report / 2021 Water Quality Report (Spanish)
2020 Water Quality Report / 2020 Water Quality Report (Spanish)
2019 Water Quality Report
2018 Water Quality Report
2017 Water Quality Report
2016 Water Quality Report
2015 Water Quality Report
2014 Water Quality Report
2013 Water Quality Report
2012 Water Quality Report

Annual Water Quality Results comparison for Reservoir 6 and West Hartford Service Areas.
2019 Water Quality Annual Results
2018 Water Quality Annual Results
2017 Water Quality Annual Results
2016 Water Quality Annual Results
2015 Water Quality Annual Results
2014 Water Quality Annual Results
2013 Water Quality Annual Results


The MDC’s untreated water comes entirely from surface water sources in watersheds that cover approximately 89.7 square miles. A watershed is considered all the land area that drains to a particular water course or water body, such as a reservoir. The MDC’s water supply comes from the East Branch of the Farmington River and the Nepaug River, a tributary of the Farmington River. The reservoirs are: the 30-billion gallon Barkhamsted Reservoir, impounded by the Saville Dam, located about one mile east of New Hartford; and the 9-billion gallon Nepaug Reservoir, created by the Phelps Brook and Nepaug Dams, located about one mile northwest of Collinsville. Both reservoirs are in Connecticut’s northwest hills, roughly 20 miles from Hartford. These relatively remote, less developed watershed locations help reduce the chance of pollution. Even so, the MDC aggressively implements various source protection programs to further ensure the quality of its reservoir supplies.


The sources of drinking water (both tap water and bottled water) can include rivers, lakes, streams, ponds, reservoirs, springs and wells. As water travels over the surface of the watershed land or through the ground, it removes naturally occurring minerals, and in some cases, radioactive material. Radon, a radioactive gas found commonly in well water, is not present in MDC water since all its drinking water is initially derived from surface water reservoirs. The water may also pick up substances resulting from the presence of animals or from human activity within the watershed areas.

Contaminants that may be present in source water include: Microbes, such as viruses and bacteria, which may come from septic systems, agricultural livestock operations and wildlife; Inorganic contaminants, such as salts and metals, which can be naturally occurring or result from urban storm water runoff, industrial or domestic wastewater discharges into septic leach fields, and mining or farming; Pesticides and herbicides, which may come from a variety of sources, such as agriculture, urban storm water runoff and residential uses; Radioactive contaminants, which can be naturally occurring.

To ensure that tap water is safe to drink, the EPA establishes regulations that limit the amount of certain contaminants in water provided by public water systems. The U.S. Food and Drug Administration is in the process of establishing regulations for contaminants in bottled water, which would provide similar protection for public health. 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.


According to the EPA, Perfluoroalkyl and Polyfluoroalkyl Substances (PFAS) are a group of manufactured chemicals that have been used in industry and consumer products since the 1940s because of their
useful properties. There are thousands of different PFAS, some of which have been more widely used and studied than others. One common characteristic of concern of PFAS is that many break down very slowly and can build up in people, animals, and the environment over time. Initial research suggests that exposure to PFAS at elevated levels may be linked to health problems.

The MDC completed testing for twenty-nine different PFAS compounds in 2023 as part of a new round of EPA-required UCMR testing. The MDC completed four rounds of testing in 2023 and can report that NONE of the 29 PFAs compounds (or lithium) required for testing by the EPA have been detected in the MDC’s water supply. MDC will keep our customers informed on plans to comply with state and federal water quality standards for PFAS as they are developed by our regulators. The MDC also tested its water supply for PFAS compounds in 2013 and 2014 as part of a previous EPA Unregulated Contaminant Monitoring Rule (UCMR) testing. No PFAS were detected in any of the samples taken. The MDC’s surface water reservoirs are well protected with no known sources of PFAS in or around the watershed. See below link for more about UCMR testing.
UCMR5 Information
Fifth Unregulated Contaminant Monitoring Rule (UCMR 5) Information

On April 10, 2024, the EPA announced the final National Primary Drinking Water Regulation (NPDWR) for six PFAS.  EPA finalized a National Primary Drinking Water Regulation (NPDWR) establishing legally enforceable levels, called Maximum Contaminant Levels (MCLs), for six PFAS in drinking water. PFOA, PFOS, PFHxS, PFNA, and HFPO-DA as contaminants with individual MCLs, and PFAS mixtures containing at least two or more of PFHxS, PFNA, HFPO-DA, and PFBS using a Hazard Index MCL to account for the combined and co-occurring levels of these PFAS in drinking water. EPA also finalized health-based, non-enforceable Maximum Contaminant Level Goals (MCLGs) for these PFAS.  Note that the six PFAS that the rule was established for have been tested for and not detected in the MDC’s water supply.

The final rule requires:

  • Public water systems must monitor for these PFAS and have three years to complete initial monitoring (by 2027), followed by ongoing compliance monitoring. Water systems must also provide the public with information on the levels of these PFAS in their drinking water beginning in 2027.
  • Public water systems have five years (by 2029) to implement solutions that reduce these PFAS if monitoring shows that drinking water levels exceed these MCLs.
  • Beginning in five years (2029), public water systems that have PFAS in drinking water which violates one or more of these MCLs must take action to reduce levels of these PFAS in their drinking water and must provide notification to the public of the violation. 

Check the EPA’s website for more Information on PFAS:


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. The MDC is responsible for providing high quality drinking water, but cannot control the variety of materials used in plumbing components. When your water has been sitting in the residential plumbing for several hours, you can minimize the potential for lead exposure by flushing your tap for 30 seconds to two minutes before using water for drinking or cooking. Another simple way to reduce the possible exposure to lead is to regularly clean your faucet screens to remove material that may become trapped in the screen. Some of that material may be lead particles from your home’s internal plumbing. Finally, do not use hot water from the tap to make infant formula or for cooking. Hot water may have higher mineral content than the cold water supplied by the MDC. Infants and young children who drink water containing lead in excess of the action level could experience delays in their physical or mental development. Children could show slight deficits in attention span and learning abilities. Adults who drink water containing lead in excess of the action level over many years could develop kidney problems or high blood pressure. Infants and young children are typically more vulnerable to lead in drinking water than the general population. While the MDC uses no lead pipes in its distribution system, it is possible that lead levels may be elevated in your home, which is a result of materials used in your home’s plumbing.

Copper is an essential nutrient, but some people who drink water containing copper in excess of the action level over a relatively short amount of time could experience gastrointestinal distress. Some individuals who may drink water containing elevated copper in excess of the action level over many years could suffer liver or kidney damage. People with Wilson’s disease should consult their personal health care provider.


EPA Water Resource Center: (800) 832-7828
EPA Safe Drinking Water Hotline: (800) 426-4791
CT Department of Public Health: (860) 509-7333

Environmental Protection Agency – Basic Information about lead in drinking water

CT Department of Public Health – Lead in Drinking Water Fact Sheet