A watershed is the total area that drains directly across the land and indirectly through the groundwater, to a particular stream, river, pond or reservoir. Precipitation that falls anywhere in the watershed of a given reservoir or stream will eventually end up in that body of water.
We protect watersheds because all activities within them have impacts - some small, some great - on their water quality.
A History of Protected Source Waters
The best way to deliver clean, safe water is to start with high quality source water. Since the 1870s, planners have sought relatively pristine and protected water sources for metropolitan Boston, ones that would require minimal water treatment. Historically, ever larger and more distant reservoirs have been secured in central and western Massachusetts to supply both the quantity and the quality of water needed. As a result, MWRA inherited in 1985 a water system whose sources - the Wachusett, Quabbin and the Ware River - are the least polluted available and require a minimal level of treatment - disinfection and corrosion control.
MWRA and Department of Conservation and Recreation Watershed Protection efforts continue this heritage by assuring that the quality of the source water is as high as it can be.
| Quabbin Reservoir | 412 billion gallons |
| Wachusett Reservoir | 65 billion gallons |
| Ware River | Amount varies: Water can be drawn from the Ware River if needed. When the Ware River flow is above 85 mgd during the period from October 15 to June 15, withdrawals are sent to the Quabbin Reservoir. |
Protecting Backup Supplies
In addition to its source reservoirs, MWRA maintains backup water supplies throughout the metropolitan area. While these waterbodies do not have to meet stringent daily drinking water quality requirements, they are kept on standby status to be used in case of emergency.
| Sudbury Reservoir | 7.3 billion gallons |
| Foss Reservoir | 1.2 billion gallons |
| Norumbega Reservoir | 205 million gallons |
| Chestnut Hill Reservoir | 522 million gallons |
| Spot Pond Reservoir | 1.8 million gallons |
Once water has been treated at the Carroll Water Treatment Plant in Marlborough or the Brustch Water Treatment Facility in Ware, it is transported by aqueducts, tunnels and pipelines towards users. Along the way, it is stored in covered storage reservoirs and tanks to balance the demand from high and low periods of use each day. The water is safely protected all the way from the reservoir, through treatment and covered storage on its way to the user.
| Norumbega | 115 million gallons |
| Carroll | 45 million gallons |
| Nash Hill | 25 million gallons |
| Fells | 20 million gallons |
| Loring Road | 20 million gallons |
| Arlington | 2 million gallons |
| Bear Hill | 6 million gallons |
| Bellevue | 3.7 million gallons |
| Turkey Hill | 2 million gallons |
| Walnut Hill | 2 million gallons |
| Spot Pond | 20 million gallons |
Integrated Water Supply Improvement Program
A Stronger, Safer Water System
MWRA’s Integrated Water Supply Improvement program is a 10-year, $1.7 billion series of projects to protect watersheds, and to build new water treatment and transmission facilities.
Main Components of the Program
Watershed Protection Programs
Watershed protection and management are the foundations of good water quality. 75% of the Quabbin, Ware River and Wachusett watersheds are DCR-owned and protected open space or regulated by the Watershed Protection Act. Programs are in place to purchase an additional 1,500 acres per year, build sewer systems to eliminate poor septic systems near critical tributaries, and keep birds and other wildlife away from intake areas.
Disinfection Improvements
MWRA meets EPA’s “CT” requirements to control bacteria and giardia. Water chemistry adjustments have also resulted in lower lead levels caused by old, corroded household pipes. The William A. Brutsch Water Treatment Facility was opened in 2000 to provide effective disinfection for the Chicopee Valley Aqueduct system.
John J. Carroll Water Treatment Plant
This facility treats up to 405 million gallons of water from the Wachusett Reservoir each day, using ozone and ultraviolet light (UV) as primary disinfectants and chloramines for residual disinfection. This treatment allows MWRA to meet current and tougher future state and federal water quality standards. The plant came on-line in July, 2005.
more information
MetroWest Water Supply Tunnel
This 17.6-mile long, deep-rock tunnel enhances the security, capacity and reliability of MWRA’s entire water transmission system. The MetroWest Water Supply Tunnel connects the new Carroll Treatment Plant to the greater Boston area. This will become the main transmission line, with the Hultman Aqueduct serving as the back-up. It went on-line in 2003.
more information
Water Storage Tanks
We have recently built four covered storage tanks to replace small open reservoirs near cities and towns. This lessens the risk that contaminants will get into your tap water and is required by the State Department of Environmental Protection (DEP) rules. Tanks in Stoneham (Fells), Ludlow (Nash Hill), Weston (Loring Road and Norumbega) and in the Blue Hills (Quincy) are now complete. An additional tank in the Northern Low Pressure Zone, are planned.
more information
Pipeline Rehabilitation
Over 2,000 miles (about 33%) of locally-owned water mains are old, corroding iron pipes in need of rehabilitation. MWRA’s Local
Pipeline and Water System Assistance Program provides $466 million in zero-interest loans to communities for relining or replacing local pipes. MWRA also has an aggressive program to rehabilitate its own 300-mile distribution network of larger pipes leading to the community systems, improving water quality and systems reliability.
MWRA's water system is made up of over 300 miles of pipeline. The structural integrity of our water pipes and aqueducts is critical. Well-maintained pipes give MWRA customers the full benefits of our high-quality water and reliable service.
Rehabilitation and Replacement
Certain older water pipes, especially those made of unlined cast-iron or concrete, need to be replaced or cleaned and lined to prevent bacteria growth and rust build-up.
Our Distribution Pipeline Improvement program is structured to replace on average between six and seven miles of pipe per year. These projects are closely coordinated with local town officials and road improvement projects.
Local Pipeline and Water System Assistance Programs
MWRA’s Local Pipeline Assistance Program was completed in June, 2013 with the distribution of $222 million in interest-free loans to MWRA water communities to perform local water main rehabilitation projects. The MWRA provided assistance to cities and towns within the water service area for rehabilitation of their locally-owned water distribution systems. About 33% of the 6,400 mile network of community pipes are older unlined pipes. The goal of the program was to maintain water quality by aiding communities in the improvement of the local pipes that water must pass through to reach consumers.
LPAP Allocation and Funding Utilization by Community through June 2013
MWRA’s Local Water System Assistance Program (LWSAP) provides a total of $725 million in interest-free loans to member water communities to perform water system improvement projects. Go to the Local Water System Assistance Program page for more information.
