Cal. Government Code § 20972

If a person has been employed by the state or one or more contracting agencies in any relative order and regardless of whether the employment was before or after the effective date of the contract, and if he or she has not been paid his or her accumulated contributions, or having been paid those contributions, he or she redeposits them, he or she shall receive credit for all state service and those employers shall be liable for all state service rendered in their respective employments and that service shall be included in the calculation of the liability of the respective employers under the contracts. A member who has been employed other than concurrently by two or more employers shall not be denied credit under this section for service prior to the contract date because of intervening employment with the same employer after the contract date and under circumstances that did not qualify him or her for prior service credit under Section 20931 or 20933. Any member who reentered this system prior to October 1, 1957, and who did not have a right to redeposit withdrawn contributions because of provisions of this section existing prior to that date may redeposit those contributions in accordance with Section 20750.