California Code, Government Code - GOV § 21230

(a) A safety member who is retired for service, with at least 20 years of service in corrections or at a jail, may serve without reinstatement from service retirement or loss or interruption of benefits provided by this system upon appointment by a contracting agency described in subdivision (b) to the position of superintendent, deputy superintendent, or captain of a jail or other adult correctional facility of the contracting agency to which state inmates have been transferred pursuant to an agreement, having a term of 20 years, described in Section 2910 or 2910.5 of the Penal Code.  Appointments under this section shall be reported to the board and shall be accompanied by the resolution adopted by the governing body of the contracting agency.

(b) This section applies only if the appointing contracting agency is a city that does not maintain a municipal police department.