Mo. Rev. Stat. § 250.233
Any city, town, village, or sewer district operating a sewerage system or waterworks may establish, make and collect charges for sewerage services, including tap-on fees. The charges may be set as a flat fee or based upon the amount of water supplied to the premises and shall be in addition to those charges which may be levied and collected for maintenance, repair and administration, including debt service expenses. Any private water company or public water supply district supplying water to the premises located within said city, town, village, or sewer district shall, at reasonable charge upon reasonable request, make available to such city, town, village, or sewer district its records and books so that such city, town, village, or sewer district may obtain therefrom such data as may be necessary to calculate the charges for sewer service. Prior to establishing any such sewer charges, public hearings shall be held thereon and at least thirty days' notice shall be given thereof.
§ 250.233, RSMo