S.D. Codified Laws § 31-14-13
At the time of entering into a contract under § 31-14-11, the contractor shall execute to the county a satisfactory bond with sufficient surety, to be approved by the board of county commissioners, or a certified check in the total sum of the contract, conditioned that the contractor will fulfill his contract according to the plans and specifications and account for all moneys paid to him, and pay all bills and claims on account of supplies, materials, or labor used in connection with or consumed in carrying on of any work in connection with such contract including all demands of subcontractors, and such bond or certified check shall stand as security for the faithful performance of said contract and for the payment of all such bills, claims, and demands. Such contract and bond or certified check shall be filed in the office of the county auditor.
SDCL 31-14-13