Cal. Wat. Code § 31032.1
A district may, pursuant to the notice, protest, and hearing procedures in Section 53753 of the Government Code, fix, as an alternative to the charge prescribed by Section 31031, in each fiscal year, water standby or availability assessments of not to exceed thirty dollars ($30) per acre per year for each acre of land, or thirty dollars ($30) per year for each parcel of land less than an acre within the district to which water is made available for any purpose by the district, whether the water is actually used or not, unless the standby charge is imposed pursuant to the Uniform Standby Charge Procedures Act (Chapter 12.4 (commencing with Section 54984) of Part 1 of Division 2 of Title 5 of the Government Code). The board of directors of a district that fixes the assessment may establish schedules varying the assessment according to the land uses and the degree of availability or quantity of use of water to the affected lands, and may restrict the assessment to lands lying within one or more improvement districts within the district. If the procedures set forth in this section as it read at the time a standby charge was established were followed, the board of directors may, by resolution, continue the charge pursuant to this section in successive years at the same rate. If new, increased, or extended assessments are proposed, the board shall comply with the notice, protest, and hearing procedures in Section 53753 of the Government Code.
A district may elect to have the assessments for the fiscal year collected on the tax roll in the same manner, by the same persons and at the same time as, together with and not separately from, its general taxes. In that event, it shall cause a written report to be prepared and filed with the secretary which report shall contain a description of each parcel of real property and the amount of the assessment for each parcel for the year.
Ca. Water Code § 31032.1