California Code, Water Code - WAT § 390.1

(a) A public entity shall conduct a water usage demand analysis prior to completing, or as a part of, a cost-of-service analysis conducted to set fees and charges for water service that are consistent with Section 6 of Article XIII D of the California Constitution and other applicable law.  Within the water usage demand analysis, a public entity shall identify both of the following:

(b) The costs of water service and the average annual volume identified in paragraphs (1) and (2) of subdivision (a) shall be made publicly available by posting the information in the public entity's cost-of-service analysis.