S.D. Codified Laws § 43-41B-8
Any deposit, including any interest thereon, made by a subscriber with a utility to secure payment for or any sum paid in advance for utility services to be furnished in this state, less any lawful deductions, is presumed abandoned if it has remained unclaimed by the person appearing on the records of the utility entitled thereto for more than one year after the termination of the services for which the deposit or advance payment was made.
Any sum which a utility has been ordered to refund and which was received for utility services rendered in this state, together with any interest thereon, less any lawful deductions, is presumed abandoned if it has remained unclaimed by the person appearing on the records of the utility entitled thereto for more than one year after the date it became payable in accordance to the final determination or order providing for the refund.
SDCL 43-41B-8