Public Utilities Code § 240
CHAPTER 1. General Provisions and Definitions
“Water system” includes all reservoirs, tunnels, shafts, dams, dikes, headgates, pipes, flumes, canals, structures, and appliances, and all other real estate, fixtures, and personal property, owned, controlled, operated, or managed in connection with or to facilitate the diversion, development, storage, supply, distribution, sale, furnishing, carriage, apportionment, or measurement of water for power, irrigation, reclamation, or manufacturing, or for municipal, domestic, or other beneficial use.