Gov. Code, § 22900

(a) Notwithstanding any other provision of this part, the County of Mariposa and the employees’ exclusive representative may agree that the employer contribution for health coverage shall be subject to the following:

(1) In the case of employees represented by a bargaining unit, a memorandum of understanding regarding health coverage, mutually agreed upon through collective bargaining, or, in the case of employees not represented by a bargaining unit, a resolution adopted by a majority of the county board of supervisors, providing as follows:

(A) Establishing the amount of its employer contribution for its annuitants or employees at any amount equal to or above that of the adjusted employer contribution required by subdivision (b) of Section 22892.

(B) Providing an employer contribution amount for annuitants that is higher than the employer contribution provided for employees, except that any employer contribution may not be less than the adjusted employer contribution required by subdivision (b) of Section 22892. This subparagraph shall only apply to an employee who retired before the effective date of the memorandum of understanding or resolution adopted pursuant to subdivision (a). If the memorandum of understanding or resolution establishes a retroactive effective date, this subparagraph shall apply only prospectively, and any employee who retires before the memorandum of understanding is signed or the resolution is adopted shall be subject to this subparagraph.

(2) This subdivision shall not affect the obligations or benefits of either the annuitants or the county that exist at the time of the enactment of this section.

(b) The County of Mariposa shall provide, in the manner prescribed by the board, a notification of the agreement established pursuant to this section and any additional information necessary to implement this section.