Cal. Education Code § 49472

The governing board of any school district or districts which does not employ at least five physicians as full-time supervisors of health, or the equivalent thereof, may provide, or make available, medical or hospital service, or both, through nonprofit membership corporations defraying the cost of medical service or hospital service, or both, or through group, blanket or individual policies of accident insurance or through policies of liability insurance from authorized insurers, for injuries to pupils of the district or districts arising out of accidents occurring while in or on buildings and other premises of the district or districts during the time such pupils are required to be therein or thereon by reason of their attendance upon a regular day school of such district or districts or while being transported by the district or districts to and from school or other place of instruction, or while at any other place as an incident to school-sponsored activities and while being transported to, from and between such places. No pupils shall be compelled to accept such service without his consent, or if a minor without the consent of his parent or guardian. The cost of the insurance or membership may be paid, from the funds of the district or districts, or by the insured pupil, his parent or guardian. Such insurance may be purchased from, or such membership may be taken in, only such companies or corporations as are authorized to do business in California.