S.D. Codified Laws § 8-9-4
Every civil township in this state shall, through its board of supervisors, enter into a contract for fire-fighting equipment and protection with a political subdivision or subdivisions of this state or with a nonprofit fire protection corporation or association legally organized and certified in this state. No contract may have a term that exceeds ten years in length. The amount of money each township pays shall be determined through negotiation and shall be specified in the contract. Any political subdivision or nonprofit fire protection corporation or association providing fire protection services shall, as part of any negotiation conducted pursuant to this section, provide full disclosure of the fire department's total assets and expenses and estimate the cost of fire protection, including equipment, buildings, material, and personnel. A contract entered into pursuant to this section shall be for an amount equal to the estimated cost of fire protection as agreed to by the parties. The contract may be for an amount other than the estimated cost of fire protection if agreed to by the parties to such contract. The provisions of this section do not apply to any township or portion thereof that lies within a rural fire protection district established pursuant to chapter 34-31A or an emergency services district established pursuant to chapter 34-47. However, nothing in this section prevents any township and rural fire district from entering into a contract to coordinate and cooperate for mutual fire protection and prevention purposes within any area which they might logically serve.
SDCL 8-9-4