Rev. & Tax. Code, § 1623

(a) The term of office of members selected to serve on assessment appeals boards shall be three years beginning on the first Monday in September except that upon the original selection of members to serve on an assessment appeals board, the member first selected shall serve for a term of three years beginning on the first Monday in September following the date of the creation of the board, the second member selected shall serve for a term of two years beginning on such date, and the third member selected shall serve for a term of one year beginning on such date.

(b) In the event of a vacancy on a board, the person selected to fill the vacancy shall serve for the remainder of the unexpired term.

(c) Not less than 60 days prior to the expiration of the term of office of any member of an assessment appeals board and upon the occurrence of a vacancy on any such board, each member of the board of supervisors shall nominate one person for each office or vacancy to be filled. The presiding judge of the superior court shall select by lot one person from among those nominated to serve for the succeeding term on such board or to fill the vacancy as the case may be.

(d) Upon expiration of the term of office of any member of an assessment appeals board, the member whose term has expired shall continue to serve until such time as a new member takes office.

(e) A member whose term has expired may continue to serve for up to 60 days after the expiration of such term with respect to matters on which the assessment appeals board had commenced hearing prior to the expiration of the member’s term.