Mo. Rev. Stat. § 327.421: Political subdivisions not to use unlicensed architects, professional engineers or professional land surveyors.

This state and its political subdivisions including counties, cities and towns, or legally constituted boards, agencies, districts, commissions and authorities of this state shall not engage in the construction of public works involving the practice of architecture, engineering or land surveying, unless the architectural and engineering drawings, specifications and estimates and the plats and surveys have been prepared by an architect, professional engineer or professional land surveyor whose license is current and in good standing, as the case may require.