The following essential services are permitted in any district: the erection, construction, alteration, or maintenance, by public utilities or municipal or other governmental agencies of systems, including gas, electrical, steam or water transmission or distribution systems; collection, communication, supply or disposal systems; elevated and underground water storage tanks; poles, wires, mains, drains, sewers, pipes, conductance, 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 of such public utilities or municipal or other governmental agencies or for the public health or safety or general welfare, but not including buildings.