Okla. Stat. tit. 11 § 37-206
District sewers and district water distribution lines shall be established within the limits of the districts, to be prescribed by ordinance. District sewers shall connect with public sewers or other district sewers, or with the natural course of drainage, as each case may be. District water distribution lines in contiguous or noncontiguous areas may connect with public distribution lines, or other district distribution lines. The governing body shall cause sewers and/or district water distribution lines to be constructed in each district whenever the record owners of more than one-half the area of land liable to assessments for the improvement shall petition therefor. The petition shall be filed with the city clerk. The petition shall state in bold, capitalized letters at the top of the page that the cost of the proposed improvements shall be assessed against the property benefited by the improvements. The districts may include mains and submains where the same are within the limits of the district or are necessary outlets or supply lines thereto.
Okla. Stat. tit. 11, § 37-206