Cal. Gov. Code § 3515

Except as otherwise provided by the Legislature, state employees shall have the right to form, join, and participate in the activities of employee organizations of their own choosing for the purpose of representation on all matters of employer-employee relations. State employees also shall have the right to refuse to join or participate in the activities of employee organizations, except that nothing shall preclude the parties from agreeing to a maintenance of membership provision, as defined in subdivision (i) of Section 3513, or a fair share fee provision, as defined in subdivision (k) of Section 3513, pursuant to a memorandum of understanding. In any event, state employees shall have the right to represent themselves individually in their employment relations with the state.