S.D. Codified Laws § 4-11-7
Nothing contained in this chapter prevents a public corporation from employing a private accountant to examine and audit the books and accounts thereof or of any of its officers if the governing body or authorized official believes that the public interest requires it, and if such employment is first approved by the auditor-general. No private audit may be paid for before a copy thereof is filed with and approved by the auditor-general. The entity receiving audit services may approve progress payments proportionate to the audit work completed so long as ten percent of the amount billed is withheld pending approval by the auditor-general of the final report. The auditor-general may accept such audit in lieu of an examination otherwise required to be made by the auditor-general.
SDCL 4-11-7