Cal. Wat. Code § 31631
By May 1 of each year the board shall have prepared and presented to it an engineering survey and report concerning the groundwater supplies within the district. The report shall include the condition of the groundwater supplies, the need for replenishment, and recommendations for any replenishment program, including the source and amount of replenishment water, the cost of purchasing or producing, transporting, and spreading this water, and the cost of "in lieu" programs, including incentives to use Colorado River water or reclaimed water in place of groundwater. In connection with any proposed replenishment program, the report shall also describe the area or areas benefited, either directly or indirectly, the amount of water production produced in each area during the prior year, and shall recommend the amount of assessment to be levied upon all production within the benefited area or areas.
Ca. Water Code § 31631