This industry group comprises establishments primarily engaged in operating water treatment plants, or operating water supply systems; operating sewer systems, or operating sewage treatment facilities; and/or providing steam, heated air, or cooled air. Establishments in this industry group may perform one of the following activities: (1) operate water pumping stations, aqueducts, and/or distribution mains; (2) operate sewer treatment facilities that collect, treat, and dispose of waste; and (3) operate steam, heated air, or cooled air supply facilities (the steam may be through mains).