S.D. Codified Laws § 5-18A-4
Competitive sealed bids required
Contracts shall be awarded by the use of competitive sealed bids except as otherwise provided in this chapter and chapters 5-18B , 5-18C , and 5-18D .
Source: SL 2010, ch 31, § 5.
S.D. Codified Laws § 5-18A-4