Gov. Code, § 31499.13

(a) An active member governed by the provisions of this article may elect, by written notice filed with the board, to make contributions and receive credit in this retirement system for service with the county that was rendered prior to his or her current membership in the system and for which he or she would not otherwise be entitled to receive credit pursuant to this article.

(b) Notwithstanding any other provision of this chapter, service credit received by a member pursuant to this section may not be counted to meet the minimum qualifications for service or disability retirement, additional cost-of-living benefits, health care benefits, or any other benefits based on service credit.

(c) Any member who elects to make contributions and receive service credit pursuant to this section shall contribute to the retirement fund, prior to the effective date of his or her retirement or, if applicable, prior to the date provided in Section 31485.7, by lump-sum payment or by installment payments over a period not to exceed 10 years, an amount that is equal to the present value of the additional liability incurred by the system in crediting the prior service, based upon actuarial assumptions in effect for the retirement system at the time the election is made.

(d) No member may receive any service credit under this section for which he or she has not completed payment pursuant to subdivision (c) before the effective date of his or her retirement or, if applicable, before the date provided in Section 31485.7. Subject to the limitations of federal law, a member who has elected to make payments in installments may complete payment by lump sum at any time prior to the effective date of his or her retirement.

(e) Any sums paid by a member pursuant to this section shall be considered to be and administered as contributions by the member.

(f) This section is not operative until the board of supervisors elects, by resolution adopted by a majority vote, to make this section operative in the county.