Del. Code tit. 31 § 4508
If a regional authority is created as provided in this chapter, 1 person shall be appointed as a commissioner of such authority for each community for which such authority is created. When the area of operation of a regional authority is increased to include an additional community or communities as provided in this chapter, 1 additional person shall be appointed as a commissioner of such authority for each such additional community. Each such commissioner appointed for a municipality shall be appointed by the mayor thereof, by and with the advice and consent of the governing body, and each such commissioner appointed for a county shall be appointed by the governing body thereof. The first appointment of commissioners of a regional authority may be made at or after the time of the adoption of the resolution declaring the need for such authority or declaring the need for the inclusion of such community in the area of operation of such authority. The commissioners of a regional authority and their successors shall be appointed as aforesaid for terms of 5 years except that all vacancies shall be filled for the unexpired terms.
31 Del. C. § 4508