S.D. Codified Laws § 46A-9-24

After the qualification of the original board, members to succeed those in the three groups provided for in § 46A-9-8, respectively, and to fill unexpired terms, shall be nominated and elected and shall take office, subject to the provisions of this chapter. Prior to May first of each year, on dates established by the board, an election shall be held to elect directors to succeed those whose terms are about to expire. Newly elected directors shall assume office at the first board meeting following their election and shall continue for a period of three years thereafter and until a successor is duly elected and qualified. Election of directors shall be conducted as provided by §§ 46A-9-25 to 46A-9-29, inclusive.