California Code, Government Code - GOV § 32061

If the pensioner reenters county service and is eligible for membership in this system, his rate of contribution for future years is that established for his age at the time of reentry.  He shall receive credit for all service rendered by him prior to the time of his disability retirement if he deposits into the fund within six months after his reinstatement an amount equal to that paid to him upon cancellation of his pension.