Gov. Code, § 20516

(a) Notwithstanding any other provision of this part, with or without a change in benefits, a contracting agency and its employees may agree, in writing, to share the costs of the employer contribution. The cost sharing pursuant to this section shall also apply for related nonrepresented employees as approved in a resolution passed by the contracting agency.

(b) The collective bargaining agreement or memorandum of understanding ratified by the employee bargaining unit and the governing body of the contracting agency shall specify the exact percentage of member compensation that shall be paid toward the current service cost of the benefits by members or the methodology for calculating that cost-sharing rate. The member contributions shall be contributions over and above normal contributions otherwise required by this part and shall be treated as normal contributions for all purposes of this part. The contributions shall be uniform, except as described in subdivision (c), with respect to all members within each of the following classifications: local miscellaneous members, local police officers, local firefighters, county peace officers, and all local safety members other than local police officers, local firefighters, and county peace officers. The balance of any costs shall be paid by the contracting agency and shall be credited to the employer’s account. An employer shall not use impasse procedures to impose member cost sharing on any contribution amount above that which is authorized by law.

(c) Member cost sharing may differ by classification for groups of employees subject to different levels of benefits pursuant to Sections 7522.20, 7522.25, and 20475, or by a recognized collective bargaining unit if agreed to in a memorandum of understanding reached pursuant to the applicable collective bargaining laws.

(d) This section shall not apply to any contracting agency nor to the employees of a contracting agency until the agency elects to be subject to this section by contract or by amendment to its contract made in the manner prescribed for approval of contracts. Contributions provided by this section shall be withheld from member compensation or otherwise collected when the contract amendment becomes effective. Once the contracting agency elects to be subject to this section, contract amendments shall not be required to effectuate cost sharing in subsequent collective bargaining agreements or memoranda of understanding ratified by the employee bargaining unit and the governing body of the agency; provided, however, that if a collective bargaining agreement or memorandum of understanding sets forth a methodology for calculating the cost-sharing rate instead of an exact percentage, the contracting agency shall provide the retirement system with a signed side letter ratified by the employee bargaining unit and the agency indicating the exact percentage at least 90 days prior to the effective date of the cost-sharing rate as set forth in the signed side letter.

(e) For the purposes of this section, all contributions, liabilities, actuarial interest rates, and other valuation factors shall be determined on the basis of actuarial assumptions and methods that, in the aggregate, are reasonable and that, in combination, offer the actuary’s best estimate of anticipated experience under this system.

(f) Nothing in this section shall preclude a contracting agency and its employees from independently agreeing in a memorandum of understanding to share the costs of any benefit, in a manner inconsistent with this section. However, any agreement in a memorandum of understanding that is inconsistent with this section shall not be part of the contract between this system and the contracting agency.

(g) If, and to the extent that, the board determines that a cost-sharing agreement under this section would conflict with Title 26 of the United States Code, the board may refuse to approve the agreement.

(h) Nothing in this section shall require a contracting agency to enter into a memorandum of understanding or collective bargaining agreement with a bargaining representative in order to increase the amount of member contributions when such a member contribution increase is authorized by other provisions under this part.