Mo. Rev. Stat. § 71.530
Any city, town or village may contract with any corporation organized under the laws of Missouri, or doing business as a foreign corporation in the state of Missouri, for the purpose of supplying it with gas, electricity or water. The contract may be for any length of time which shall be agreed upon between the city, town or village and the corporation, for a term not to exceed twenty years. Each contract may be renewed for another period or periods for a term of not more than twenty years per period. The provisions of this section shall apply to all cities, towns and villages in this state, whether organized by special charter or under the general laws of the state, any provisions in any special charter of any city, town or village in the state to the contrary notwithstanding. All renewal contracts entered into under the provisions of this section shall be subject to voter approval of the majority of the voters voting on the question, pursuant to the provisions of section 88.251. Every initial contract for such services shall be approved by a majority of the voters of the municipality voting on the question. Nothing herein contained shall be so construed as to prevent the governing body of any city, town or village from contracting with any person, association or corporation for furnishing the city, town or village with gas, electricity or water in municipalities where franchises have already been granted and where gas, electric or water plants and facilities already exist, without a vote of the people.
§ 71.530, RSMo