Cal. GOV § 3544

(a) An employee organization may become the exclusive representative for the employees of an appropriate unit for purposes of meeting and negotiating by filing a request with a public school employer alleging that a majority of the employees in an appropriate unit wish to be represented by such organization and asking the public school employer to recognize it as the exclusive representative. The request shall describe the grouping of jobs or positions which constitute the unit claimed to be appropriate and shall be based upon majority support on the basis of current dues deduction authorizations or other evidence such as notarized membership lists, or membership cards, or petitions designating the organization as the exclusive representative of the employees. Notice of any such request shall immediately be posted conspicuously on all employee bulletin boards in each facility of the public school employer in which members of the unit claimed to be appropriate are employed.

(b) The employee organization shall submit proof of majority support to the board. The information submitted to the board shall remain confidential and not be disclosed by the board. The board shall obtain from the employer the information necessary for it to carry out its responsibilities pursuant to this section and shall report to the employee organization and the public school employer as to whether the proof of majority support is adequate.