S.D. Codified Laws § 8-9-7
Any civil township in this state may, through its board of supervisors, when and to the extent deemed expedient by the board, enter into contracts for the furnishing of ambulance service, equipment and protection for the township, with any other political subdivision or subdivisions of this state, or any fire protection, ambulance service, or funeral service corporation or association legally organized in this state. No contract authorized by this section may exceed a term of ten years. Further, no contract authorized by this section may provide for an expenditure by a township of more than one thousand dollars per year, unless it has been submitted to, and approved by, the voters of the township in the manner provided by subdivision 8-3-2(8).
SDCL 8-9-7