S.D. Codified Laws § 13-7-32
A school board resolution to increase school board terms to four years or to decrease school board terms to two years, pursuant to § 13-8-2, is subject to a referendum if five percent of the registered voters of the school district, based upon the total number of registered voters in the school district at the last preceding general election, petition, within twenty days after the resolution is enacted, to have the question of approval or disapproval of the resolution to increase or decrease term limits placed upon the ballot at the next scheduled election or at a special election called for that purpose. The business manager shall give notice that the question will be on the ballot at the next scheduled election or at a special election called for that purpose as provided by law for school elections and prepare official ballots according to the provisions of this title.
SDCL 13-7-32