Upon the issuance by the governing body of the county of bonds under this chapter such governing body shall forthwith direct the county auditor in writing to impose annually thereafter in the district the number of mills of the annual levy of taxes voted on in the election held under § 57-21-50, and the county auditor, pursuant to such written direction, shall annually thereafter levy such number of mills on the dollar on all taxable property in the district until such levy shall have produced an amount equal to the amount required to retire the interest and principal of the bonds, the proceeds of which levy shall be placed by the county treasurer, when collected, in a special fund and used as herein provided.