Cal. Gov. Code § 3515.8

Any state employee who pays a fair share fee shall have the right to demand and receive from the recognized employee organization, under procedures established by the recognized employee organization, a return of any part of that fee paid by him or her which represents the employee’s additional pro rata share of expenditures by the recognized employee organization that is either in aid of activities or causes of a partisan political or ideological nature only incidentally related to the terms and conditions of employment, or applied towards the cost of any other benefits available only to members of the recognized employee organization. The pro rata share subject to refund shall not reflect, however, the costs of support of lobbying activities designed to foster policy goals and collective negotiations and contract administration, or to secure for the employees represented advantages in wages, hours, and other conditions of employment in addition to those secured through meeting and conferring with the state employer. The board may compel the recognized employee organization to return that portion of a fair share fee which the board may determine to be subject to refund under the provisions of this section.