California Code, Business and Professions Code - BPC § 2811

(a) Each person holding a regular renewable license under this chapter, whether in an active or inactive status, shall apply for a renewal of their license and pay the biennial renewal fee required by this chapter every two years on or before the last day of the month following the month in which their birthday occurs, beginning with the second birthday following the date on which the license was issued, whereupon the board shall renew the license.

(b) A license not renewed in accordance with this section shall expire but may within a period of eight years thereafter be reinstated upon payment of the fee required by this chapter and upon submission of proof of the applicant's qualifications as may be required by the board.  During the eight-year period, no examination shall be required as a condition for the reinstatement of an expired license that has lapsed solely by reason of nonpayment of the renewal fee.  After the expiration of the eight-year period, the board may require as a condition of reinstatement that the applicant pass an examination as the board deems necessary to determine their present fitness to resume the practice of professional nursing.

(c) A license in an inactive status may be restored to an active status if the licensee meets the continuing education standards of Section 2811.5.