1. Upon the recommendation of the sewer engineer, the county commission, by resolution, shall have authority to levy a special assessment upon all lots, tracts or parcels of land, including improvements, in any sewer district established as provided in sections 249.430 to 249.660 for the maintenance, repair and administrative expense of the sewer in such sewer district or districts, the assessment to be levied according to the lots, tracts or parcels of real estate including improvements, as shown upon the assessment books prepared by the assessor of such county, such assessment not to exceed one-half of one percent of such assessed valuation; provided, however, that no assessment shall be made against any land that has not been platted and such plat finally approved by the county planning commission, county zoning commission, county planning and zoning commission, or county governing body, and against which condemnation proceedings for a trunk sewer or similar sewage handling line have been completed, unless the owner or owners of such land have petitioned for sewer service under sections 249.430 to 249.660 or have requested to tap-on to such line. The county clerk shall compute the amount of such assessment against each lot, tract or parcel of real estate in such sewer district or districts and deliver a certified copy of such assessment to the county collector. The county collector shall report such assessment to anyone making inquiry about the taxes and shall receive payment therefor, and issue a duplicate receipt therefor, one of which shall be filed with the county clerk, and such payments shall be remitted to the county treasurer who shall be required to keep a separate account thereof which shall be subject to warrants drawn on the account by the county commission, to be used only in the furtherance of the provisions of sections 249.430 to 249.660.

2. Every certified assessment shall bear interest from the date of issuance until paid, but may be paid without interest within thirty days after the date of issuance, and shall be a special tax lien against the property described therein for a period of five years from its date. The assessment levied and extended upon the books as aforesaid shall be collected in the same manner and the lien shall be enforced in the same manner as the taxes levied for state and county purposes.