Each bid shall be made in accordance with the plans and specifications on file. Each bid in excess of fifty thousand dollars shall be accompanied by a certified check, certified by a state or national bank domiciled within this state, in the sum of five percent of the total amount of the bid, or a ten percent bid bond issued by a surety authorized to do business in the state. To be effectual for any purpose the bid and certified check or bond shall be securely enclosed in a sealed envelope and deposited with the county auditor before the hour of opening the sealed bids.
SDCL 31-14-8