Cal. Business and Professions Code § 7003

Except as otherwise provided, an appointment to fill a vacancy caused by the expiration of the term of office shall be for a term of four years and shall be filled, except for a vacancy in the term of a public member, by a member from the same branch of the contracting business as was the branch of the member whose term has expired. A vacancy in the term of a public member shall be filled by another public member. Each member shall hold office until the appointment and qualification of his or her successor or until the office is deemed to be vacant pursuant to Section 1774 of the Government Code, whichever first occurs. Vacancies occurring in the membership of the board for any cause shall be filled by appointment for the balance of the unexpired term. No person shall serve as a member of the board for more than two consecutive terms. The Governor shall appoint four of the public members, including the public member who is from a statewide senior citizen organization, the local building official, the member of a labor organization representing the building trades, and the five contractor members qualified as provided in Section 7002. The Senate Rules Committee and the Speaker of the Assembly shall each appoint two public members.