S.D. Codified Laws § 25-7-6.24
Current with legislation signed by the governor on or before 3/6/2024
If the parents of a child have agreed to a change in the physical custody of the child without the court's approval, the parent who relinquished physical custody may be ordered to pay child support to the parent who gained physical custody of the child even though the custody order has not been modified to reflect the change in custody.
There is a rebuttable presumption that a parent has agreed to a change in physical custody if the change has occurred for a period of one hundred twenty consecutive days or more and the parent has not formally objected to the court, even in the absence of a formal written agreement.
SDCL 25-7-6.24