Cal. Gov't Code § 20815.6

(a) Upon request and not to exceed once every five years, the board shall, within its existing resources, perform a separate computation of the assets and liabilities as of the most recent actuarial valuation date, as determined by the actuary, for a county and a trial court that elect to separate their joint contract. Upon completion of the computation under subdivision (c), the trial court shall enter a separate contract in accordance with Chapter 5 (commencing with Section 20460) and the assets and liabilities of the trial court shall be moved to its individual contract.
(b) Each respective trial court and county described in subdivision (a) shall identify and send to the board all of the following information within 90 days of election to separate the joint contract:
1. (1) The starting and ending appointment dates for all active, inactive, and retired members that are considered county employees or trial court employees. The trial court and county shall jointly agree upon the following about those members:
  1. (A) Their appointment dates.
  2. (B) Whether a member is a county employee or trial court employee for purposes of the computation under subdivision (c).
2. (2)
  1. (A) The amount and payment date of any additional discretionary payments made by either the county or the trial court to the system.
  2. (B) The amount and allocation of any additional discretionary payments described in subparagraph (A) shall be jointly agreed upon by the respective county and trial court and validated by the system before those additional discretionary payments are used in the computation to separate the joint contract.
(c) Within 90 days of receipt of the information described in subdivision (b), the board shall forward the computation described in subdivision (a) to the respective county and trial court. The computation and separation shall be based on the most recent actuarial valuation at the time the data described in subdivision (b) is received by the board. The county and trial court shall have 30 days to review the computation and provide any additional information required for clarification or correction or to revoke their election to separate the joint contract. The board shall only consider information that is jointly confirmed by both the trial court and county. Subsequent to the deadline for the provision of information for correction, the board shall have 180 days to amend the computation and to separate the joint contract into individual contracts for the county and trial court. If either the county or the trial court revokes its election to separate the joint contract, the joint contract shall remain in effect.