Cal. Gov. Code § 31117

Any person who previously had permanent status in a civil service system of any county and who vacated his position to accept appointment to an elective position shall be reinstated to his former position in the same county if he so desires at the termination of such appointment, or term of office if his acceptance of such appointment was without a break in continuity of service and if such person does not run for election to succeed himself following his period of appointment.