Cal. Government Code § 31755.2

Notwithstanding any other provision of law: (a) (1) The Board of Supervisors of Contra Costa County may, pursuant to a memorandum of understanding in accordance with the Meyers-Milias-Brown Act (Chapter 10 (commencing with Section 3500) of Division 4 of Title 1), adopt a resolution making this section applicable to the officers and employees of the county specified in the resolution and specifying the future operative date of its application. (2) After the board of supervisors has adopted that resolution, the governing body of a district may make this section applicable to its officers and employees by adopting a resolution specifying the future operative date of its application, which date may not be earlier than the operative date of the resolution described in paragraph (1). (b) Notwithstanding any other provision of law, the benefit formula set forth in Section 31676.16 shall apply to the Tier Three service with which a member, who retires on or after the date this section becomes applicable in the county or district, is entitled to be credited and for which the member has paid Tier Three member contributions. (c) Notwithstanding any other provision of law, Section 31676.16 does not apply to any periods of service performed as Tier Two service under Section 31751, except to the extent that Tier Three service credit is purchased by or on behalf of the member for those periods. (d) If the county adopts a resolution pursuant to subdivision (a), this section shall apply equally to any nonrepresented employees in similar job classifications as employees within applicable bargaining units and to the supervisors and managers of those employees.