Cal. Government Code § 21264

Retired members of this system, and beneficiaries who are entitled to receive allowances or benefits under this part, may authorize deductions to be made from their retirement allowance payments or from the allowances and benefits, respectively, or from either or both if both are being received, in accordance with regulations or procedures established by the board for the payment of group insurance premiums and other premiums for benefits or protection provided for under Section 1151, including employer-sponsored voluntary insurance programs, for credit union payments or shares, or for the payment, with respect to any retired member of this system, of dues or for any other services pursuant to Article 6 (commencing with Section 1150) of Chapter 1 of Division 4 of Title 4. The board shall determine the additional cost involved in making deductions under this section and the state agency, the public agency, the association, or the unit thereof, or the credit union shall pay the amount of the additional cost to the board for deposit in the retirement fund.