S.D. Codified Laws § 9-47-1
Every municipality may construct, establish, operate, and maintain a system of waterworks and facilities in connection therewith; may regulate the distribution and use of water supplied thereby; may acquire a suitable supply of water, whether within or without the municipality; may maintain dams, reservoirs, intakes, spillways, conduits, or other devices to gather and store surface, flood, or other waters within or without the municipality either as a direct source of water to the municipality or as a supply of water from which any other source of the water supply of the municipality may be replenished or restored; may advantageously dispose of, to districts, subdivisions, and areas, outside the limits of the municipality to which supply lines may extend, any municipal supply of water, including stored water, not required or used for municipal purposes and any surplus water may be disposed of to any outside district where the water is delivered into a natural watercourse for irrigation purposes; may assess, levy, and collect taxes and special assessments for such purposes; and may appropriate funds and levy taxes to accumulate funds for such purposes, as provided by this title. The accumulated funds shall be placed in a separate fund which may not revert at the end of the fiscal year. The governing body shall establish a maximum amount allowed to be accumulated in the fund. The fund shall be established by a resolution adopted pursuant to chapter 9-19. Every municipality may enter into agreements with the United States, with the state, and with any authorized agency, subdivision, or unit of government, federal or state, to carry out such purposes.
SDCL 9-47-1