Cal. Education Code § 46014

Pupils, with the written consent of their parents or guardians, may be excused from school in order to participate in religious exercises or to receive moral and religious instruction at their respective places of worship or at other suitable place or places away from school property designated by the religious group, church, or denomination, which shall be in addition and supplementary to the instruction in manners and morals required elsewhere in this code. Such absence shall not be deemed absence in computing average daily attendance, if all of the following conditions are complied with: (a) The governing board of the district of attendance, in its discretion, shall first adopt a resolution permitting pupils to be absent from school for such exercises or instruction. (b) The governing board shall adopt regulations governing the attendance of pupils at such exercises or instruction and the reporting thereof. (c) Each pupil so excused shall attend school at least the minimum school day for his grade for elementary schools, and as provided by the relevant provisions of the rules and regulations of the State Board of Education for secondary schools. (d) No pupil shall be excused from school for such purpose on more than four days per school month. It is hereby declared to be the intent of the Legislature that this section shall be permissive only.