Cal. Ed. Code § 87715
A full-time contract or regular classroom instructor currently employed by a community college district that decides to maintain classes on Saturday or Sunday, or both, shall not, without his or her written consent, be required to instruct under that program for more than 180 full days during a college year, or for more than the number of full days the colleges of the district were maintained during the year preceding implementation of weekend classes, whichever is greater. This section shall not be construed as limiting the power of any governing board of a community college district to govern the colleges of the district, including the assignment of instructors employed by the district. No such classroom instructor shall be assigned to perform services on a Saturday or Sunday if the instructor objects in writing that the assignment would conflict with his or her religious beliefs or practices.
Ca. Educ. Code § 87715