Cal. Elec. Code § 10408

When the county precinct boundaries at a consolidated election called by the board of supervisors of the county in which the city, district or other political subdivision is located do not coincide with the boundaries of the city, district or other political subdivision, the board of supervisors may by order, and for the purpose of the election only, reprecinct the territory in which the boundaries do not coincide, at any time prior to 30 days before the election.