California Code, Government Code - GOV § 3508.5

(a) Nothing in this chapter shall affect the right of a public employee to authorize a dues or service fees deduction from his or her salary or wages pursuant to Section 1157.1, 1157.2, 1157.3, 1157.4, 1157.5, or 1157.7.

(b) A public employer shall deduct the payment of dues or service fees to a recognized employee organization as required by an agency shop arrangement between the recognized employee organization and the public employer.

(c) Agency fee obligations, including, but not limited to, dues or agency fee deductions on behalf of a recognized employee organization, shall continue in effect as long as the employee organization is the recognized bargaining representative, notwithstanding the expiration of any agreement between the public employer and the recognized employee organization.