Mo. Rev. Stat. § 640.648
Notwithstanding any law to the contrary, all Missouri landowners retain the right to have, use, and own private water systems and ground source systems anytime and anywhere including land within city limits, unless prohibited by city ordinance, on their own property so long as all applicable rules and regulations established by the Missouri department of natural resources are satisfied. All Missouri landowners who choose to use their own private water system shall not be forced to purchase water from any other water source system servicing their community.
(L. 2001 H.B. 501 § 4 merged with S.B. 462 § 1)