Mo. Rev. Stat. § 108.030: Interest and principal of indebtedness — annual tax on tangible property (county).

Before incurring any indebtedness under the provisions of sections 108.010 and 108.020 the county shall provide for the collection of an annual tax on all taxable tangible property therein sufficient to pay the interest and principal of the indebtedness as they fall due, and to retire the same within twenty years from the date contracted.