S.D. Codified Laws § 9-44-8
The municipality may agree that in the event of a deficiency in the improvement fund, the governing body will levy an ad valorem tax upon all of the taxable property within the municipality in an amount as may be necessary to pay the deficiency. The covenant may be limited to the levy of a tax for the payment of any deficiency existing at the maturity of the last outstanding bond, or may provide for the levy of a tax whenever any amount of principal or interest shall become due and the moneys in the fund shall be insufficient to pay the same. Notwithstanding the omission of a covenant in the resolution authorizing the bonds, or the limitation of the same to payment of a deficiency at the maturity of the last outstanding bond, the governing body may levy a tax upon the occurrence of any deficiency, and may also levy such tax in anticipation of any deficiency for the purpose of paying the next maturing principal and interest. Taxes levied pursuant hereto may not exceed by more than five percent the deficiency for which they are levied, but are not subject to any other limitation as to rate or amount; and levies in excess of such limitation shall be invalid only as to the excess.
SDCL 9-44-8