Cal. Government Code § 3507.1

(a) Unit determinations and representation elections shall be determined and processed in accordance with rules adopted by a public agency in accordance with this chapter. In a representation election, a majority of the votes cast by the employees in the appropriate bargaining unit shall be required. (b) Notwithstanding subdivision (a) and rules adopted by a public agency pursuant to Section 3507, a bargaining unit in effect as of the effective date of this section shall continue in effect unless changed under the rules adopted by a public agency pursuant to Section 3507. (c) A public agency shall grant exclusive or majority recognition to an employee organization based on a signed petition, authorization cards, or union membership cards showing that a majority of the employees in an appropriate bargaining unit desire the representation, unless another labor organization has previously been lawfully recognized as exclusive or majority representative of all or part of the same unit. Exclusive or majority representation shall be determined by a neutral third party selected by the public agency and the employee organization who shall review the signed petition, authorization cards, or union membership cards to verify the exclusive or majority status of the employee organization. In the event the public agency and the employee organization cannot agree on a neutral third party, the California State Mediation and Conciliation Service shall be the neutral third party and shall verify the exclusive or majority status of the employee organization. In the event that the neutral third party determines, based on a signed petition, authorization cards, or union membership cards, that a second labor organization has the support of at least 30 percent of the employees in the unit in which recognition is sought, the neutral third party shall order an election to establish which labor organization, if any, has majority status.