Mo. Rev. Stat. § 272.370
The county commission may on its own motion and shall upon the petition of one hundred real estate owners of ten acres or more of the county submit to the voters at a general or special election the proposition for the adoption by the county of the provisions of sections 272.210 to 272.370. The commission shall cause notice of the election to be published in a newspaper published within the county, or if no newspaper is published within the county, in a newspaper published in an adjoining county, for three weeks consecutively, the last insertion of which shall be at least ten days before the day of the election, and by posting printed notices thereof at three of the most public places in each township in the county. If a majority of the voters voting on the proposition vote in favor of the adoption of the provisions of sections 272.210 to 272.370 the county commission shall issue an order declaring the adoption. From and after the issuance of the order the provisions of sections 272.210 to 272.370 shall be in full force and effect in the county and the provisions of sections 272.010 to 272.140 shall be suspended in the county.
§ 272.370, RSMo