S.D. Codified Laws § 49-34A-100
Upon receiving filing under § 49-34A-99 for a rate adjustment pursuant to the tariff established in § 49-34A-98, the commission may approve, reject, or modify the annual rate adjustment after notice and opportunity for hearing. In making its decision, the commission shall consider whether the costs and expenses included for recovery through the tariff were or are expected to be prudently incurred, will achieve environmental improvements at the lowest reasonable cost to ratepayers, and will allow the public utility to recover costs consistent with its allowed return on equity. To the extent the environmental improvement may affect the following, the commission may also consider whether the environmental improvement is likely to enhance adequate utility service, rate stability, the financial stability of the public utility, reasonable capital costs, just and reasonable rates, a fair rate of return, and other considerations that benefit the public interest.
SDCL 49-34A-100