249.787.  Estimate of expenses — tax levy, how collected. — 1.  Before the tenth day of May of each year the board of supervisors of any district organized under the provisions of sections 249.760 to 249.810 shall make an estimate of the amounts required to defray the expenses of the district.

  2.  The estimates shall be certified by the secretary of the board and filed by the clerk of the county in which the district lies.  Upon the basis of these estimates the county commission shall levy an ad valorem tax on all taxable real property within the district sufficient to provide the necessary funds.

  3.  The clerk of the county commission shall enter the levies on the tax books in the same manner as school district taxes are entered, for the use of the county collector.  The taxes thus levied and extended upon the tax books shall be collected at the same time and in the same manner as the taxes levied for state and county purposes and the taxes when collected shall be remitted by the collector to the treasurer of the district.