ESSENTIAL SERVICES. The erection, construction, alteration, or maintenance, by public utilities or municipal or other governmental agencies, of underground or overhead gas, electrical, steam, or water transmission or distribution systems; collection, communication, supply, or disposal systems, including poles, wires, mains, drains, sewers, pipes, conduits, cables, fire alarm boxes, police call boxes, traffic signals, hydrants, and other similar equipment and accessories in connection therewith, reasonably necessary for the furnishing of adequate service by such public utilities or municipal or other governmental agencies or for the public health, safety, or general welfare, but not including buildings.