The power and authority given to health districts, except as otherwise provided by ORS 440.315 to 440.410, is vested in and shall be exercised by a board of directors each of whom shall be an elector of the district. [Formerly 441.280; 1979 c.520 §1; 1983 c.83 §86; 1983 c.350 §255; 1983 c.699 §5]