S.D. Codified Laws § 4-2-17

For purposes of §§ 4-2-15 and 4-2-16, an audit is timely if the audit report is submitted to the Department of Legislative Audit not later than eighteen months following the end of the entity's fiscal year. If the entity is performing a two-year audit, the audit is timely if the audit report is submitted to the department not later than eighteen months following the end of the entity's second fiscal year covered by the audit.