California Code, Public Resources Code - PRC § 49010

At the conclusion of the hearing, the board of supervisors shall either adopt an order abandoning the creation of the proposed district or shall, by resolution, order the matter of the creation of the district, within the boundary lines determined upon at the hearing, to be submitted to the voters registered in the proposed district at an election to be called for that purpose.

At the election only voters registered in the proposed district shall be permitted to vote.