HOW WATER GETS TO YOUR TAP

Protected Reservoirs

MWRA's water comes from the Quabbin Reservoir, about 65 miles west of Boston, and the Wachusett Reservoir, about 35 miles west of Boston. The two reservoirs combined supplied an average of 214.21 million gallons per day to consumers in 2007. The Quabbin alone can hold a supply of 4-year supply of water.

The reservoirs are filled naturally. Rain and snow fall onto watersheds (protected land around reservoirs) and eventually turn into streams that flow into reservoirs. This water comes into contact with soil, rock, plants and other material as it follows its path. This process helps to clean the water, and it can also dissolve and carry very small amounts of material into the reservoir.

The Quabbin and Wachusett Reservoirs are protected. Over 85% of the watershed lands that surround the reservoirs are covered in forest and wetlands. About 75% of the total watershed land cannot be built on. The natural undeveloped watersheds help to keep MWRA water clean and clear. Also, to ensure safety, the streams and the reservoirs are tested often and patrolled daily by the Massachusetts Department of Conservation and Recreation (DCR). Because they are well-protected, the water in the Quabbin and Wachusett Reservoirs is considered to be of very high quality.

Generating Power as it Goes

Quabbin water enters the Wachusett Reservoir at Oakdale and circulates for eight months before being drawn off in Clinton. Electric power is generated as the water both enters and leaves the reservoir and at two other stations in the system.

Tested Each Step of the Way

MWRA tests over 1,500 water samples per month, from the reservoirs all the way to household taps. Annual and monthly test results are posted on mwra.com.

Treatment

MWRA's licensed treatment operators treat drinking water according to strict state and federal regulations.

• MetroWest and Metro Boston communities: Water for these cities and towns is treated at the new John J. Carroll Water Treatment Plant at Walnut Hill in Marlborough. Water from the Quabbin and Wachusett reservoirs enters the plant through the Cosgrove or Wachusett Aqueduct.

Water Treatment Steps - Carroll Water Treatment Plant

1. Water is disinfected with ozone gas bubbles. Ozone is a safe, natural disinfectant derived from oxygen.
2. Chloramines are added to protect water from potential contamination as it is carried long distances through pipelines.
3. pH is adjusted with sodium carbonate and carbon dioxide. Adjusting pH reduces the chances that metal particles from home plumbing could dissolve into tap water.
4. Fluoride is added for healthy teeth.

Water leaves the plant through the MetroWest Water Supply Tunnel.

• Chicopee Valley area customers - (Chicopee, South Hadley Fire District #1, Wilbraham): Water for these communities is treated in at the Ware Water Treatment Facility in Ware, Massachusetts. Water from the Quabbin Reservoir enters the facility through the Quabbin Aqueduct.

  Water Treatment Steps - Ware Water Treatment Facility

  1. Water is disinfected with measured doses of chlorine.

  Water leaves the plant through the Chicopee Valley Aqueduct. Each community also treats the water to reduce the chances that metal particles from home plumbing could dissolve into tap water.

Toward Your Community

Chicopee Valley area (Chicopee, South Hadley Fire District #1, and Wilbraham): Water for these communities is treated in at the Ware Water Treatment Facility in Ware, Massachusetts. Water from the Quabbin Reservoir enters the facility via the Quabbin Aqueduct.

For MetroWest and Metro Boston communities - through the MetroWest Water Supply Tunnel and is stored in covered tanks. From there it is drawn into distribution mains and the many smaller pipes that the region. Water meters log the water entering each community.

Into Your Home

Local pipes serve each street and eventually carry water into buildings. Meters installed by the local community measure the amount of water delivered to each home or business.

Back to top

Updated September 18, 2008