California Code, Health and Safety Code - HSC § 4717

At the conclusion of the hearing, or if an election is held and the canvass of the election returns shows that a majority of all the votes cast in the entire proposed district and that a majority of the votes cast on the question in each city or part thereof in the proposed district were in favor of the formation of the district, the board of supervisors may, if it deems best, make an order forming the district.