Essential Services - means the erection, construction, alteration, or maintenance by public utilities or by governmental departments or commissions of such underground or overhead gas, electrical, steam, or water transmission or distribution systems and structures, collection, communication, supply or disposal systems and structures, including towers, poles, wires, mains, drains, sewers, pipes, conduits, cables, fire alarm boxes, police call boxes, street lights, traffic signals, hydrants and other similar equipment, and accessories in connection therewith, but not including buildings or microwave radio relay structures, as are reasonably necessary for the furnishing of adequate service by such public utilities or governmental departments or commissions, or as are required for protection of the public health, safety, or general welfare. For the purpose of this definition, the word "building" does not include "structures" for essential services.