Cal. Welf. & Inst. Code § 18101

The board of supervisors making the appointments shall designate one member to serve for one year, two for two years, two for three years, and two for four years, and upon the resignation or expiration of the term of each, his successor shall in like manner be appointed for the term of four years. Appointments to fill vacancies caused by death, resignation, or removal shall be made for the residue of such terms in the same manner as the original appointments. (Added by Stats. 1965, Ch. 1784.)