S.D. Codified Laws § 13-28-9
School residence for the purpose of claiming free school privileges means the legal residence of the student's parents or guardian except as provided in § 13-28-10. If a parent or guardian has more than one residence, the school residence is the residence where the parent or guardian actually lives and makes a home or domicile. In case of dispute, if the student's parent or guardian has claimed a credit pursuant to § 10-13-39, it is presumed that the dwelling so claimed is the residence of the parent or guardian. The student or the student's parents or guardian may not establish school residence and be exempt from the payment of tuition if the residence of the parents or guardian of the student is acquired solely or principally for obtaining free school privileges. At the time a child is enrolled in a school district, the school residence of the child as determined by that school district within thirty days after the enrollment may not change during the school fiscal year, unless the child ceases to be an enrolled member of a school within the district. If a student's parents or guardians are separated or divorced, the school residence is the school district in which the custodial parent or guardian has residence. If the parents or guardian have joint custody of a student, school residence is that of the parent or guardian with whom the child resides the greater portion of the school year.
Notwithstanding the provisions of any other law, if the parent or guardian of a child is transferred to or is pending transfer to a military installation within the state while on active military duty pursuant to an official military order, the child meets the residency requirement for free school privileges in the school district in which the parent or guardian resides or will reside.
For the purposes of this section, a military installation is a base, camp, post, station, yard, center, or other installation under the jurisdiction of the United States Department of Defense.
SDCL 13-28-9