S.D. Codified Laws § 9-8-1.1

An individual may be nominated, elected, or appointed as a mayor or as an alderman, if the person is a citizen of the United States, a voter of the municipality, and a resident of the municipality in accordance with § 9-14-2. An alderman representing a ward must be a voter of and resident of the ward for which the person is to hold office. If the mayor or an alderman at large moves to a permanent residence outside the corporate limits of the municipality, the office is immediately vacated. If an alderman representing a ward moves to a permanent residence outside the boundaries of his or her ward, the office is immediately vacated.