S.D. Codified Laws § 11-9-27
With respect to the municipality, the county, school districts and any other local governmental body having the power to levy taxes on real property located within a district, the calculation of the assessed value of taxable real property in a district, for purposes of computing the dollar and cents rates of such taxing units, may not exceed the tax increment base of the district until the district is terminated. The dollar and cents rates of all taxing units shall be assessed and extended against all taxable real property in the district at its current assessed value. However, no change in the laws of this state affecting taxation of real property may result in a lesser rate for the tax increment base until the district is terminated pursuant to this chapter.
SDCL 11-9-27