Mo. Rev. Stat. § 91.450
Any city of the third or fourth class, and any town or village, and any city now organized or which may hereafter be organized and having a special charter, and which now has or may hereafter have less than thirty thousand inhabitants, shall have power to erect or to acquire, by purchase or otherwise, maintain and operate, waterworks, gas works, electric light and power plant, steam heating plant, or any other device or plant for furnishing light, power or heat, telephone plant or exchange, street railway or any other public transportation, conduit system, public auditorium or convention hall, which are hereby declared public utilities, and such cities, towns or villages are hereby authorized and empowered to provide for the erection or extension of the same by the issue of bonds therefor, and any city, town or village which may own, maintain or operate, and which may hereafter acquire, by purchase or otherwise, and operate, or which may engage in the construction of any of the plants, systems or works mentioned in this section, is hereby authorized and empowered to establish, by ordinance, within such city, town or village, an executive department to be known as "The Board of Public Works", to consist of four persons, electors of said city, town or village, who have resided therein for a period of two years next before their appointment, or any resident of the county that receives services from such board, who shall be appointed by the mayor of such city, town or village, and confirmed by the common council in such manner as other appointive officers of such city, town or village are appointed and confirmed. The members of such board shall hold office for a term of four years each, or until their successors are appointed and qualified; provided, that the members of said board shall hold office for a term of four years each, except the first incumbents, as members of said board of public works, who shall be appointed and hold office for the term of one, two, three and four years respectively.
§ 91.450, RSMo