Mass. Gen. Laws ch. 140 § 206
Every public and semipublic outdoor inground swimming pool shall be enclosed by a fence six feet in height and firmly secured at ground level provided that any board or stockade fence or structure shall be at least five feet in height, but if over five feet in height, the fence shall be chain link. Such enclosure, including gates therein, shall not be less than six feet above the ground, and any gate shall be self-latching with latches placed four feet above the ground or otherwise made inaccessible from the outside to children up to eight years of age. Such enclosure shall be constructed of such material and maintained so as not to permit any opening in said enclosure, other than a gate, wider than three inches at any point along the enclosure. Any such pool shall be equipped with at least one life ring and a rescue hook.
Every outdoor inground swimming pool open to the public, other than a public inground swimming pool fed by a spring or stream shall be drained or covered within seven days of closing.
For the purposes of this section, "semipublic outdoor inground pool" shall mean a swimming or wading pool on the premises of, or used in connection with, a hotel, motel, trailer court, apartment house, country club, youth club, school, camp, or similar establishment where the primary purpose of the establishment is not the operation of the swimming facilities. Semipublic outdoor inground swimming pool shall also mean a pool constructed and maintained by groups for the purposes of providing bathing facilities for members and guests only.
Every public and semipublic outdoor inground swimming pool shall be inspected annually by the inspector of buildings of each city and town in which said pool is located.
Any owner or manager of such public or semipublic pool who fails to comply with the provisions of this section shall be punished by a fine of not more than one thousand dollars.
Mass. Gen. Laws ch. 140, § 206