California Code, Government Code - GOV § 20772.5

(b)(1) The Military Department shall notify the member of his or her total rate of contributions and the amount of the monthly contribution payable by him or her to the retirement fund. The member shall transmit his or her contribution with respect to the service described in the notice by the Military Department. The Military Department shall transmit the contributions to the system as described in rules and regulations adopted by the board.

(2) If the member fails to pay the contribution within one month after receipt of the notice, the amount of contribution due shall accrue interest, at the rate described in Section 20059, as calculated by the Military Department, with interest to be added to the amount owed for the subsequent month. The system shall not be obligated to attempt to collect any delinquent payments. A member may not be credited with service under this part until the contribution with respect to that service, plus any accrued interest, is paid in full.