Water entering Quabbin takes up to four years to circulate and enter the main intake. Electric power is generated as the water both enters and leaves the reservoir and at two other stations in the system. The water then passes through pipes under the Sudbury Reservoir, which is not presently used, to Southborough. Here, fluoride, a mineral that helps prevent tooth decay, is added to the water. It is then chlorinated as it is drawn into distribution mains, which feed nine small distribution reservoirs and storage tanks and the many smaller pipes serving the region.
Water meters log the water entering each community.
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.