No contract of a municipality is valid unless the contract has been authorized by a vote of the governing body at an official meeting.
Each written contract must be executed in the name of the municipality by the mayor or president of the board of trustees, be countersigned by the finance officer, and have the corporate seal attached. However, the governing body of a municipality may, by ordinance or resolution, delegate to any employee of the municipality the authority to enter into a contract on behalf of the municipality and to execute the contract and any other instrument necessary or convenient for the performance of the contract subject to the limitations delegated by the governing body.
SDCL 9-1-5