S.D. Codified Laws § 9-43-137
If public moneys are made available by loan from any federal source to the state, an agency of state government, a public body created by the state, or a political subdivision of the state for the direct or indirect aid of landowners or owners of real property in the public or private improvement of their property in a manner specified by competent federal, state, or local authority, the owners are entitled to retire their obligations for the improvements in like pro rata installments over the same period of time as the loan of federal moneys will be retired, or, if permissible, to accelerate the installments as they are able, and at the same rate of interest as the loan of federal moneys to the state, state agency, public body, or political subdivision of the state. However, if the loan of federal moneys requires different or more stringent terms be met by the owners with regard to time period, installments, or rate of interest, then the terms allowed shall be the most liberal possible that still comply with the federal requirements.
The provisions of this section, in a proper case, are in lieu of assessment under any other law granting power to assess for property improvement.
SDCL 9-43-137