Cal. Water Code § 37855

The board of directors and officers of the surviving district shall peform all duties and functions of the board of directors and corresponding officers of the water storage district relating to the assessment, levy, and collection of assessments with respect to assessments levied but uncollected as of the date of the merger in the same manner and at the same times as is provided in the California Water Storage District Law, and all county officers and boards of supervisors shall likewise perform their functions and duties with relation to the assessment, levy, and collection of such assessments as is provided in the California Water Storage District Law.