California Code, Government Code - GOV § 21061

(a) A local safety member, other than one subject to Section 21362or 21362.2, shall be retired for service upon the member's written application to the board if the member has attained the age of 55 years, and is credited with five years of state service.

(b) Subdivision (a) does not apply to the employees of any contracting agency having a contract with the board made prior to September 5, 1945, which contract specifies an age greater than the age of 55 years as the minimum age for voluntary retirement for service for local safety members, until the agency elects to make subdivision (a) applicable to its employees, by amendment to its contract made in the manner prescribed for the approval of contracts, except that an election among the employees is not required.

Until the contracting agency elects to make subdivision (a) applicable to its employees, a local safety member employed by the contracting agency shall be retired for service upon the member's written application to the board if the member has attained the minimum age for voluntary retirement specified in the contract between his or her employer and the board, and is credited with five years of state service.