Norumbega Reservoir is an integral part of the Hultman Aqueduct, built 1938-40 to bypass the Sudbury Reservoir and Aqueduct. The aqueduct is now part of a pressure system extending from Wachusett Reservoir into Boston and adjacent communities. Norumbega Reservoir is the central point for chlorination in the water supply systems. Screens in the gatehouse are used to filter out debris and fish that may be carried in the aqueduct from Wachusett Reservoir. Hultman Aqueduct was built under the authority of the Metropolitan District Water Supply Commission by contractor Carlo Bianchi & Co, Framingham.