Mo. Rev. Stat. § 77.490

The council may, by ordinance, regulate and fix reasonable maximum rates and charges for the rental and use of telephones and telephone service within such city, and the price and quality of water, gas, gasoline, petroleum, electric lights and other means of lighting furnished by any person, firm or corporation operating under any franchise granted by the city, and may prescribe the candle power of the gas and electric lights furnished the city and private consumers. The council may, by ordinance, regulate and fix reasonable maximum rates, charges and prices of steam heat or other means of heating furnished by any person, firm or corporation operating under any franchise granted by the city, and may prescribe the pressure to be maintained, on its mains, by any steam heating company, person or firm operating the same.