S.D. Codified Laws § 11-2-17.7
Any alteration, construction, use of earthmoving equipment, or other change pursuant to a zoning permit or allowed land use on neighboring land that began after the date on which an application for a conditional use is received, and that causes the application to fail to meet one or more of the criteria or requirements for conditional use under the zoning ordinance, does not cause the request for a conditional use permit to be considered nonconforming until a final disposition of the conditional use request is determined pursuant to § 11-2-61 or 11-2-65. If the conditional use permit is granted, the conditional use shall be considered a lawful use, lot, or occupancy of land or premises and may be continued even though the use, lot, or occupation does not conform to the provisions of the ordinance. If the conditional use is not pursued by the applicant for a period of more than one year, any subsequent use, lot, or occupancy of the land or premises shall conform with the zoning ordinance.
SDCL 11-2-17.7