California Code, Government Code - GOV § 20900

(a) Notwithstanding any other provision of this part, a member employed on a part-time basis on and after January 1, 1976, shall, for the period of part-time employment, receive the credit the member would receive if he or she was employed on a full-time basis and have his or her retirement allowance, as well as any other benefits the member is entitled to under this part, based upon the salary that he or she would have received if employed on a full-time basis, if the member and his or her employer both elect to contribute to the retirement fund the amount that would have been contributed if the member was employed on a full-time basis.  Prior to the reduction of an employee's workload under this section, the district personnel responsible for the administration of this program, in conjunction with the administrative staff of the State Teachers' Retirement System and this system, shall verify the eligibility of the applicant for the reduced workload program.  This section shall be applicable only to a member who meets the following criteria:

(b) The employer shall maintain the necessary records to separately identify each employee receiving credit pursuant to this section.