Water Code § 71454
CHAPTER 1. Elections Generally
Except with respect to formation elections, whenever lands situated in more than one county are included in a district:
(a) The secretary shall perform all duties prescribed by law to be performed by county clerks or registrars of voters, as the case may be, in connection with district elections.
(b) Where necessary, the secretary is authorized to procure from the proper county officials all necessary registration books and copies of indexes thereof.
(c) The board shall perform all duties prescribed by law to be performed by boards of supervisors in connection with district elections.