S.D. Codified Laws § 13-26-17

If a school board authorizes year-round school pursuant to § 13-26-2, the school board's decision to schedule the opening day of classes before the first Tuesday following the first Monday in September may be referred to a vote of the qualified voters pursuant to § 13-26-9. If the decision to schedule the opening day is not referred, or if the referendum is rejected by the qualified voters, the decision shall remain in effect and is not subject to further referendum pursuant to § 13-26-9 for the subsequent consecutive years that the year-round school plan is implemented by the school board.