Cal. Government Code § 31646.5

(a) A member who wishes to apply for a nonservice-connected disability retirement allowance may, to the extent necessary to qualify for that allowance, receive service credit for a period of continuous, uncompensated leave immediately preceding the filing of the application upon satisfaction of all of the following: (1) The member has exhausted all compensated leave, including any catastrophic leave to which the member may be eligible. (2) The leave of absence was due to the member’s medical condition that has been determined by the board to be a terminal illness. (3) Payment by the member of the contributions the member would have paid during the leave of absence, together with interest those contributions would have earned had they been on deposit if the member were not absent. The contributions may be paid in a lump sum, or may be paid on a monthly basis for a period of not more than the length of the period for which service credit is claimed; provided, however, that payment shall be completed prior to the effective date of the member’s retirement, or in accordance with Section 31485.7 or 31485.8 if either section has been adopted by the board of supervisors. (b) Credit may not be received pursuant to this section for a period in excess of 12 consecutive months. (c) This section shall not apply in any county unless and until it is adopted by a majority vote of the board of supervisors.