Fishing Boat
Water Quantity and Why it Matters for Massachusetts Rivers

Maintaining sufficient water levels in our rivers and  streams to support natural species, habitat, public supply, and river recreation is an important goal for the Massachusetts Rivers Alliance and its members. Surface and groundwater withdrawals, as well as other competing demands of our water resources, contribute to the amount of water left in-stream to support aquatic ecosystems. It's an ongoing challenge for the state to balance human demands while also providing adequate streamflow for wildlife and habitat. Natural streamflow is threatened by development, particularly in Eastern Massachusetts where a growing population has increasing water demands, leading to degraded fisheries and wetlands, limits water-based recreation, and compromises water supplies.

More than 60 communities in Massachusetts rely on water supplies from the Quabbin and Wachusett reservoirs (supplied by the Massachusetts Water Resources Authority). For other Massachusetts residents on public or private water systems, water comes from groundwater wells that draw on storage in underlying aquifers or surface water supplies (reservoirs, lakes, or rivers). For more information, please see the 'State' section below. To see how water is bought, sold, and moved across the state between public water suppliers and the MWRA, check out our interactive GIS map! 

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Map created by John Doolin.


The federal government doesn’t regulate water quantity (streamflow) or drinking water quality, so the responsibility for implementing the federal Safe Drinking Water Act (1974) has been delegated to the states.


The need for water in eastern Massachusetts was recognized years ago when the Quabbin Reservoir in western Massachusetts was built in the 1930’s to supply drinking water to Boston and surrounding towns. This was, and continues to be, the largest interbasin transfer of water within the state. The Massachusetts Water Resources Authority’s website discusses the history of the development of its water system, including the Quabbin ( The purpose of the Interbasin Transfer Act (1984) is to assure that any transfer of water or wastewater from a river basin protects the water-dependent resources of the donor basin. It is administered by the Massachusetts Water Resources Commission, and though it does not prohibit such transfers, it requires a review. More information can be found at: The purpose of the Water Management Act (WMA), effective in March 1986, is to regulate large water withdrawals so that Massachusetts has sufficient water for its various needs, including the needs of the environment. The act regulates surface water and groundwater withdrawals that average 100,000 gallons per day (GPD). Specifically, any new or additional withdrawals of 100,000 GPD or more since 1985, require a permit from the Massachusetts Department of Environmental Protection (MassDEP). Permits are issued for up to 20 years, with reviews of permits every five years. MassDEP issues permits on a rotating, watershed-wide basis for the state's 28 major river basins. Permitted withdrawals are subject to the Act's 2014 revised regulations, which require some permittees to reduce impacts of their withdrawals on streamflow and aquatic habitat. Thus, permitted water suppliers must comply with certain conditions, such as water use restrictions during droughts, and requirements to control “unaccounted for water use.” Municipalities can’t use more water than the Department of Conservation and Recreation (DCR) predicts they will need within the 20-year permit period, according to that agency’s Water Needs Forecast for each town. The exceptions to these rules are “registered” water withdrawals, which allowed water withdrawals existing between 1981 and 1985 to be grandfathered in under registrations. Registrations are renewed every 10 years and are not currently subject to the same conditions as permits, which reduce impacts of withdrawals and impose water conservation measures. About 85% of the state’s water use, including use by the Massachusetts Water Resources Authority’s, is registered. MassDEP would need to promulgate new regulations or condition the registrations in order to require these users to comply with conservation conditions, but this would not require a legislative change. New regulations for the Water Management Act were promulgated in 2014, as a result of a nearly five-year long multi-stakeholder “Sustainable Management Initiative,” in an effort to better balance human water demand against the needs of the environment for water, and to prevent streams from drying up in the summer due to excessive water use. The new regulations created new “Sustainable Yields” for each basin that river advocates feel are unrealistically large (and not sustainable). The new regulations also created new rules requiring large water users impacting streams to decrease their water use, and communities seeking large increases to “mitigate” their use by implementing water recharge projects or other actions to improve stream health. You can find information about the Sustainable Water Management Initiative, including scientific reports upon which the new policy is based, and watershed maps here: You can find the Water Management Act, its regulations, policies, and guidance, here: The State of Massachusetts created a set of Conservation Standards in 2006 that are updated periodically, and can be found here: