The governing body of the district shall consist of five supervisors, elected or appointed under this chapter. The supervisors shall be persons residing within the district who are by training or experience, or both, as determined by the district qualified to perform the services which will be required of them, and shall not be employees of the federal government. Advisory supervisors may be appointed to a district board by a majority vote of the supervisors of that district. Term of office shall be designated at the time of appointment, and they shall serve without compensation. (Amended 1959, No. 329 (Adj. Sess.), § 11(c), eff. March 1, 1961; 1967, No. 303 (Adj. Sess.), § 10, eff. March 22, 1968; 1995, No. 163 (Adj. Sess.), § 6, eff. May 15, 1996.)