Cal. Water Code § 31673

A certified copy of the ordinance or resolution determining that any land is entitled to a special rate of taxation shall be delivered to the county assessor, and thereafter until notified of a change in the determination, he shall enter the land described in the ordinance or resolution separately on the assessment roll and so designate it and the percentage of the regular rate of taxation to which it is entitled that it may readily be distinguished from other land not entitled to a special rate.