California Code, Government Code - GOV § 31680.15

(a) On and after January 1, 2018, a person who has retired under this chapter may serve without reinstatement from retirement or loss or interruption of benefits under this chapter, as an elective officer.

(b) If a retired person serves without reinstatement from retirement in an elective office and part or all of his or her retirement allowance is based on service in that elective office, the portion of the allowance based on service in that elective office shall be suspended during incumbency in that elective office.  The entire retirement allowance shall be paid for time on and after the person vacates the elective office in the monthly amount payable had the allowance not been suspended.