SDCL § 9-40-31: Expenditures from depreciation account--Investment of accumulations.

The funds accumulating to the depreciation account shall be expended in balancing depreciation in such utility, or in making any constructions, extensions, or additions thereto. Any such accumulations may be invested as the governing body may designate, to the same extent and in the same manner as any other funds of the municipality may be invested as otherwise provided by law; and if invested, the income from such investment shall be carried into the depreciation account.