California Code, Elections Code - ELEC § 12281

(a) If, for any valid reason, the polling place designated for any precinct cannot be used, and this fact is known in sufficient time to allow a mailed notice to be received before the election, the elections official may designate another polling place and shall mail, to each voter in the precinct a notice showing this change.

(b) If the information is not known in sufficient time for a mailing pursuant to subdivision (a), either the elections official or, in the case of an emergency, the precinct board on the day of election, shall designate another polling place as near the place first designated as possible, post notice on or near the place first designated, and conduct the election at the new location.

(c) This section does not apply to elections conducted using vote centers.