S.D. Codified Laws § 46A-14-15.1
For purposes of this chapter, the term, eligible voter, has the meaning specified in this section. Only persons or public corporations that are landowners of land located within the proposed or existing watershed district are eligible to vote in the formation election or any subsequent election of a watershed district, except as provided in this chapter. An eligible voter may reside within or outside the district. Any firm, partnership, limited liability company, association, estate, or corporation that holds title to land located within the proposed or existing watershed district is entitled to one vote and may designate an officer or agent to vote on its behalf by presenting a written instrument to that effect to the election officials. The vote of any eligible voter who is a minor or a protected person as defined by § 29A-5-102, may be cast by the parent, conservator, or legal representative of the minor or protected person. Any municipality that has been included in the watershed district pursuant to §§ 46A-14-5 or 46A-14-7 is entitled to one vote which may be cast by a representative designated by the municipality's governing body.
SDCL 46A-14-15.1