Cal. Gov. Code § 31558.2
Notwithstanding any of the provisions of Section 31558 to the contrary, each person who, prior to the effective date of this section was employed in positions the principal duties of which consist of active law enforcement for not less than 10 years and who is employed by a county in a position which would make such person eligible to become a safety member at the time of his or her employment, may, if he or she so elects, become a safety member as of the first day of the calendar month following his or her entrance into county service.
A member may receive credit for such service, as a safety member, when he or she has contributed, with interest to the date paid, the difference between contributions made and those which would have been made by the member if he or she had been a safety member. Such additional contributions shall be made prior to retirement.
This section shall not be operative in any county until such time as the board of supervisors shall, by resolution adopted by majority vote, make the provisions of this section applicable in that county.
Ca. Gov. Code § 31558.2