Cal. Wat. Code § 35410.2
If there is more than one tax code area for the levy of said metropolitan water district tax within a district, an improvement district may be formed in the manner provided in Chapter 4.9 (commencing at Section 36410), of Part 6 of this division for any or all of said tax code areas for the purpose of providing for the payment of the whole or part of the metropolitan water district tax attributable to any tax code area. After the hearing on the resolution of intention as provided in Section 36415, or as said hearing may be continued, the board may by resolution order the improvement district formed. Thereafter in any year the board may elect to pay, from receipts, assessments or standby charges or any combination thereof levied exclusively in said improvement district, the whole or a stated percentage of the metropolitan tax for the next succeeding fiscal year attributable to the area within said improvement district, provided, that it takes similar action with respect to all other said tax code areas.
Ca. Water Code § 35410.2