Cal. Education Code § 45102

(a) For the purposes of this section every classified employee shall be deemed to be employed for 12 months during each school year regardless of the number of months in which he or she is normally in paid status. (b) If, during a school year, it is necessary to assign a regular classified employee to perform an assignment or service in addition to his or her regular assignment, a school district shall pay the classified employee on a pro rata basis for the additional assignment or service, not less than the compensation and benefits that are applicable to the classification of the additional assignment or service during the school year, unless the school district has negotiated a contract that allows for a lesser pay scale. A school district shall inform a classified employee of the compensation and benefits of the additional assignment or service before the employee commences the additional assignment or service. (c) A school district that, in any school year, maintains school sessions at times other than during the regular September–June academic year shall assign for service during those times regular classified employees of the district. (d) If it is necessary to assign classified employees not regularly so assigned to serve between the end of one academic year and the commencement of another, that assignment shall be made on the basis of qualifications for employment in each classification of service that is required. (1) A school district may not require a classified employee whose regular yearly assignment for service excludes all, or any part of, the period between the end of the academic year in June to the beginning of the next academic year in September to perform services during that period. (2) A classified employee shall, for services performed as provided in this subdivision, receive, on a pro rata basis, not less than the compensation and benefits that are applicable to the classification of the additional assignment or service during the regular academic year. (e) This section shall apply to districts that have adopted the merit system in the same manner and effect as if it were a part of Article 6 (commencing with Section 45240).