Cal. Gov. Code § 31639.9
In any county of the ninth class, as defined by Sections 28020, and 28030, as amended by Chapter 1204 of the Statutes of 1971, the board of supervisors may meet and confer pursuant to the Meyers-Milias-Brown Act with a recognized employee organization which represents county employees who are not safety members because the board of supervisors has not made Section 31469.4 applicable in the county, and endeavor to reach agreement on any conditions to be required of employees or an employee organization seeking to have Section 31469.4 made applicable, including, but not limited to, whether the employees shall be required to pay all or part of the employer's normal and cost-of-living contributions, in excess of those it would have paid if the employees had remained general members, including any increased employer normal and cost-of-living contribution rates attributable to employees who have become safety members electing to purchase credit as a safety member, pursuant to Section 31639.7, for time served in an eligible position prior to becoming a safety member.
Any contributions paid by the employees on behalf of the employer to cover the increased cost of safety retirement shall be as determined upon actuarial advice and approved by the board of retirement.
The provisions of this section shall not be applicable in any county until the board of supervisors by resolution makes the provisions applicable.
Ca. Gov. Code § 31639.9