S.D. Codified Laws § 11-6-3
The governing body of any municipality may contract with the board of county commissioners for planning and zoning services to be provided by the county, and the contract may provide that the municipality shall pay such fees as are agreed for the services performed. Under the provisions of the contract the municipal governing body may authorize the county planning and zoning commission, on behalf of the municipality, to exercise any of the powers otherwise granted to municipal planning and zoning commissions under this chapter and chapter 11-4. The contract between the governing body of the municipality and the county may provide among other things for joint county-municipal planning activities, or it may designate the county planning commission as the planning commission for the municipality. The municipality may also contract with a planning agency, authority or commission, or with planning consultants, or with other specialists for such services as it requires.
SDCL 11-6-3