California Code, Water Code - WAT § 528

(b)(1) Charge each customer for which a water meter has been installed, based on the actual volume of water delivered, as measured by the water meter, within five years of meeting the definition of urban water supplier.

(2) Notwithstanding paragraph (1), in order to provide customers with experience in volume-based water service charges, an urban water supplier that is subject to this subdivision may delay, for one annual seasonal cycle of water use, the use of meter-based charges for service connections that are being converted from nonvolume-based billing to volume-based billing.