S.D. Codified Laws § 9-21-11
The governing body may enter into a contract for any term of years as the governing body may determine with any person or any rural water system, water user district, sanitary district, water project district, or like organization for the purchase by the municipality of water, gas, or electricity. If a contract is entered into with the United States government, or any agency or department thereof, providing for the sale and purchase of water or the acquisition of a municipal water supply, the contract may be for any term of years as said governing body may determine, or for the leveling or improvement of irrigable lands belonging to the municipality, which lands were on February 20, 1953, located and situated within the boundaries of an existing irrigation district. If any contract entered into pursuant to this section extends for more than one year, an appropriation need not have been previously made concerning such expense, except sufficient to cover the amount payable or estimated to become payable under such contract for the first year thereof. The governing body shall annually thereafter appropriate an amount sufficient to cover the amount payable or estimated to become payable under such contract during the ensuing fiscal year.
Such contracts shall be subject to referendum as ordinances.
SDCL 9-21-11