As used in ORS 225.310 (Definitions for ORS 225.310 to 225.400) to 225.400 (Scope of municipal authority), unless the context requires otherwise, “facilities” means a water supply for irrigation and for fire protection of property within the city together with a distribution system therefor, reservoirs, pumps, mains, stations, with all appurtenances necessary, useful or convenient for the treatment, storage and distribution of water supply.