California Code, Revenue and Taxation Code - RTC § 1622

An assessment appeals board shall consist of three members selected by lot by the presiding judge of the superior court of the county from among those persons nominated for that purpose by the members of the county board of supervisors.  Within 60 days after the adoption of the ordinance providing for the creation of assessment appeals boards, each member of the board of supervisors shall nominate not less than three nor more than five persons for appointment to the assessment appeals boards.