Mo. Rev. Stat. § 204.332
In lieu of the method of incorporation provided in sections 249.450 and 249.460, subdistricts may be created in the following manner: Upon written recommendation of the county highway engineer, county sewer engineer, or director of public works; or upon petition of twenty percent or more of the registered voters within the area which will be liable to assessment for the construction and maintenance of a sewer system, setting forth generally the area to be included, the county commission or county legislature shall adopt a resolution to establish the subdistrict and describing generally the size and location of the proposed subdistrict. The county commission or county legislature may designate the highway engineer or director of public works as sewer engineer, or may retain the services of an engineer or firm of engineers as sewer engineers. The sewer engineer shall advise the county commission or county legislature with reference to proper boundaries of any subdistricts to be established and shall also superintend the construction of the sewers and the maintenance thereof and the apportionment of the cost thereof as provided by law. The county commission or county legislature shall also request the county clerk, clerk of the legislature, or other appropriate officer to appoint or designate a deputy to keep the special records which are required for the proceedings for the construction and maintenance of the sewer subdistricts or divisions. In addition, the requirements of sections 249.070 and 249.480, must be complied with before a sewer subdistrict can be incorporated under the provisions of sections 204.331 and 204.332.
§ 204.332, RSMo