Mo. Rev. Stat. § 393.020
It shall be lawful for any corporation organized for that purpose under chapter 351, or heretofore organized for that purpose under any laws of this state, or any foreign corporation for profit organized under or subject to chapter 351, to lay and construct an underground water main, or underground water mains, along the right-of-way of any public highways in this state, or across any stream in this state, for the purpose of furnishing, at wholesale only, a supply of water to any incorporated city, town or village, or cities, towns and villages, in this state; provided, that when it shall become necessary in laying and constructing such mains to make any excavations in any public highway, the company constructing such mains shall restore such highway to as good condition as same was in prior to the making of such excavations, and when necessary in laying and constructing such underground water main or mains every such corporation shall have the power of eminent domain and may condemn right-of-way for such underground water main or mains in the manner prescribed by law for the condemnation of rights-of-way of railroads; provided, that where such underground water mains are laid along any right-of-way of any railroad company or through or under the roadbed of any railroad, the laying of the same shall be according to standard and approved rules of construction, and in such manner as not to weaken or impair the same or the use thereof, but such construction shall be according to such standards as will insure the safety of such railroads and the operation of trains over the same.
§ 393.020, RSMo