California Code, Education Code - EDC § 17527

(a) The governing board of any school district may enter into agreements to make vacant classrooms or other space in operating school buildings available for rent or lease to other school districts, educational agencies, except private educational institutions which maintain kindergarten or grades 1 to 12, inclusive, governmental units, nonprofit organizations, community agencies, professional agencies, commercial and noncommercial firms, corporations, partnerships, businesses, and individuals, including during normal school hours if the school is in session.

(b) The governing board shall give first priority in leasing or renting vacant classroom space or other space to educational agencies for conducting special education programs and second priority to other educational agencies.