S.D. Codified Laws § 49-34B-17

For each inspection fee assessed to interstate gas pipeline operators, the commission shall calculate its total actual expenses and obligations incurred in implementing and administering this chapter. All expenses directly attributable to specific interstate gas pipeline facilities shall be directly charged to the appropriate pipeline operators on an annual basis. For all expenses not directly attributable to interstate pipeline facilities, the commission shall assess each pipeline operator for a pro rata share of the expenses and obligations based on the percentage of the total miles of pipeline to be inspected that are operated or will be operated by each pipeline operator.