Cal. Business and Professions Code § 2987.5

Every person licensed under this chapter is exempt from the payment of the renewal fee in any one of the following instances: While engaged in full-time active service in the Army, Navy, Air Force or Marines, or in the United States Public Health Service, or while a volunteer in the Peace Corps or Vista. Every person exempted from the payment of the renewal fee by this section shall not engage in any private practice and shall become liable for the fee for the current renewal period upon the completion of his or her period of full-time active service and shall have a period of 60 days after becoming liable within which to pay the fee before the delinquency fee becomes applicable. Any person who completes his or her period of full-time active service within 60 days of the end of a renewal period is exempt from the payment of the renewal fee for that period. The time spent in that full-time active service or full-time training and active service shall not be included in the computation of the three-year period for renewal of a license provided in Section 2986. The exemption provided by this section shall not be applicable if the person engages in any practice for compensation other than full-time service in the Army, Navy, Air Force or Marines or in the United States Public Health Service or the Peace Corps or Vista.