S.D. Codified Laws § 10-46A-2.2
For the purpose of this chapter, a prime contractor is a person entering into a realty improvement contract or a contract for construction services as enumerated in division c of the Standard Industrial Classification Manual, 1987, as prepared by the Statistical Policy Division of the Office of Management and Budget, Office of the President, with the United States and its instrumentalities, the State of South Dakota and its subdivisions, or any other state or public corporation, or person as defined in § 10-45-1. If a contractor engages in services not specifically listed in division c of the Standard Industrial Classification Manual, 1987, then the services must entail the construction, building, installation, or repair of a fixture to realty before the gross receipts are subject to the tax imposed by § 10-46A-1. Operative builders, industry number 1531, as enumerated in the Standard Industrial Classification Manual, 1987, as prepared by the Statistical Policy Division of the Office of Management and Budget, Office of the President, are prime contractors regardless of whether they perform construction work themselves or contract with other contractors. A person who is not primarily in the business of making realty improvements and regularly employs persons for the purpose of repairing, maintaining or making realty improvements for his own use and who repairs, maintains or makes a realty improvement for his own use with his regular employees is not a prime contractor and is not liable for the tax herein.
SDCL 10-46A-2.2