N.D. Cent. Code § 40-33-17
Any city owning and operating a system of waterworks supplying water for municipal purposes and to its inhabitants and industries may enter into a contract in the manner hereinafter set forth, with any person, firm, public or private corporation, or limited liability company able and willing to perform such contract, for the purchase and installation of a plant for the treatment of such water supply by the removal of minerals, gases, and other impurities therefrom, including, but without limiting the generality hereof, the construction of reservoirs or settling basins and furnishing of machinery and equipment for such purpose, the construction of buildings necessary to house the same, and any modifications, improvements, and additional mains necessary to connect such plant with the existing water supply system.
N.D.C.C. § 40-33-17