S.D. Codified Laws § 15-6-4(i)
Notwithstanding any other provision of law, a summons may be served upon a defendant in any action by mailing a copy of the summons, two copies of the notice and admission of service, conforming substantially to the form provided for in § 15-6-4(j), and a return envelope, postage prepaid, addressed to the sender. The notice and admission of service shall set forth that the failure to sign and return the admission of service within twenty days after the date of mailing without good cause will result in the court ordering the person so served to pay the costs of personal service.
Unless good cause is shown for not returning the admission of service to the sender within twenty days of mailing, the court shall order the payment of the costs of personal service to be paid by the defendant in the action.
SDCL 15-6-4(i)