Mo. Rev. Stat. § 249.933: Maintenance costs, assessment may be levied and collected after period for assessment of property has expired.

A sewage or storm water facility improvement district assessment may be levied and collected after the original period approved for assessment of property within the district has expired, with the proceeds thereof used solely for maintenance of the improvement, if the residents of the sewage or storm water facility improvement district vote to assess property within the district for the maintenance costs in the manner prescribed in subsection 2 of section 249.929.