S.D. Codified Laws § 46A-10A-29 (2026)
Failure of a drainage commission to act within sixty-five days from the date of an official submission to it under the provisions of § 46A-10A-28 shall be deemed approval, unless a longer period is granted by the board within the sixty-five-day period.
Source: SL 1985, ch 362 , § 29.