Mo. Rev. Stat. § 91.110: May acquire by purchase.

Every such city shall have the right and is hereby expressly given the power to acquire, by purchase, as herein provided, a waterworks system, consisting of pipes, mains, machinery, buildings, standpipes, reservoirs, easements, rights-of-way, water supply and such real estate as is necessarily connected therewith for the successful operation thereof, including the franchises and rights granted thereto by the city, and any leasehold rights, and any other water supply that may be necessary or that the city may deem necessary, whether owned by the water company or other person or corporation, and said city is hereby given the power to erect and construct such waterworks system as herein provided.