Cal. Government Code § 20460.1

(a) Except as provided in subdivision (d), for all counties that contract with the board for the provision of retirement benefits for their eligible employees as of the implementation date of the Trial Court Employment Protection and Governance Act (Chapter 7 (commencing with Section 71600) of Title 8), a trial court and a county in which the trial court is located shall jointly participate in this system by joint contract. All other counties and trial courts may elect such joint participation in accordance with the procedures set forth in this chapter. Except as provided in subdivision (b) and except as otherwise provided in this part, the trial court and the county jointly participating in this system shall each have all of the rights and all of the obligations of a contracting agency under the contract and under this part. (b) A county shall not be responsible for the employer or employee contributions required to be paid on behalf of trial court employees. A trial court shall not be responsible for the employer or employee contributions required to be paid on behalf of county employees. (c) As used in this chapter, “joint contract” means a contract with the board as set forth in subdivision (a). (d) A county and the trial court located within the county may jointly elect to separate the joint contract into individual contracts if the county and the trial court both make that election voluntarily, as specified in Section 20471.2.