S.D. Codified Laws § 5-18B-9
No bidder on a public improvement contract may be required, either in the invitation for bids or otherwise, to leave a certified check or cashier's check, or bid bond, posted for a longer period than allowed in § 5-18A-5 if the bid is not accepted. The check or bid bond of the successful bidder shall be returned upon the execution of the contract and surety hereafter provided for. The checks of all unsuccessful bidders shall be, by the purchasing agency, immediately returned to the respective makers thereof and the bid bonds of all unsuccessful bidders shall be, by the purchasing agency, immediately destroyed. No more than forty-five days may elapse between the opening of the bids and either the acceptance of the bid of the lowest responsible bidder or the rejection of all of the bids presented.
SDCL 5-18B-9