California Code, Government Code - GOV § 22823

(a) Notwithstanding Section 10270.5 of the Insurance Code, an employee who is enrolled in a board-approved health benefit plan sponsored by an employee organization that is the exclusive representative pursuant to the Ralph C. Dills Act (Chapter 10.3 (commencing with Section 3512) of Division 4 of Title 1) and who terminates his or her membership in the respective employee organization shall become ineligible for enrollment in the health benefit plan.

(b) Notwithstanding subdivision (a), the employee may continue enrollment in the employee organization health benefit plan until he or she is notified by the employee organization of the loss of eligibility.  Upon notification of the loss of eligibility, the employee within 60 days may change his or her enrollment to another health benefit plan for which the employee is eligible.