California Code, Government Code - GOV § 31641.2

(a) Twice the contributions he or she would have made to the retirement fund if he or she had been a member during the same length of time as that for which he or she has elected to receive credit as service, computed by applying the rate of contribution first applicable to him or her upon commencement of his or her membership in this system to the monthly compensation first earnable by him or her at the time as provided in Section 31641.3, multiplied by the number of months for which he or she has elected to receive credit for county service, including time, if any, prior to the establishment of the system, and which will constitute current service under this system.

(b) The “regular interest” that would have accrued to the member contributions if they had been made on the date used to determine on what earnable compensation contributions pursuant to this section shall be based, from that date until the completion of payment of those contributions, computed at the current interest rate.

(c) Except as prohibited by Section 31640.7, the governing body by a four-fifths vote may provide that it shall make on behalf of officers and employees eligible to receive credit for prior service under this chapter, and who so elect prior to filing an application for retirement, part of the contributions specified in paragraphs (a) and (b) of this section. The contributions made by a governmental agency pursuant to this section shall be available only for purposes of retirement for service or for disability and a member resigning from county service shall be entitled to withdraw only that portion of his or her accumulated contributions made by him or her.