Mass. Gen. Laws ch. 40 § 39B
For the purpose of establishing a water supply or water distributing system as authorized by section thirty-nine A, any town, by its board of water commissioners or selectmen authorized to act as such, may take by eminent domain under chapter seventy-nine, or acquire by purchase or otherwise, and hold, the waters, or any portion thereof, of any pond, brook, spring, stream or ground water sources within its limits, not already appropriated for purposes of public water supply, and any water or flowage rights connected therewith; and also for said purpose may take by eminent domain under chapter seventy-nine, or acquire by purchase or otherwise, and hold, all lands, rights of way and other easements necessary for collecting, storing, holding, purifying and treating such water and protecting and preserving the purity thereof and for conveying the same to any part of the town; provided, that no source of water supply and no lands necessary for protecting and preserving the purity of the water shall be taken or used without first obtaining the advice and approval of the department of environmental protection, and that the location and arrangement of all dams, reservoirs, wells or filter galleries, filtration and pumping plants or other works necessary in carrying out the provisions of sections thirty-nine A to thirty-nine E, inclusive, shall be subject to the approval of said department.
Mass. Gen. Laws ch. 40, § 39B