California Code, Government Code - GOV § 3209

Nothing in this chapter prevents an officer or employee of a state or local agency from soliciting or receiving political funds or contributions to promote the passage or defeat of a ballot measure which would affect the rate of pay, hours of work, retirement, civil service, or other working conditions of officers or employees of such state or local agency, except that a state or local agency may prohibit or limit such activities by its employees during their working hours and may prohibit or limit entry into governmental offices for such purposes during working hours.