Mo. Rev. Stat. § 64.865: Enforcement officer — buildings subject to his approval.

Any county commission which has adopted a zoning plan, as provided herein, shall appoint an officer or shall designate one of the existing officials to enforce the provisions thereof. After the appointment or designation of the officer or official, no building or other structure shall be erected, constructed, reconstructed, enlarged or altered, or repaired in such manner as to prolong the life of the building, nor shall the use of any land be changed without a permit issued by the officer or official.