Iowa Code § 468.136: Levy under original classification.

If the amount finally charged against a district does not exceed twenty-five percent of the original cost of the improvement in the district, the board shall proceed to levy the amount against all lands, highways, and railway rights-of-way and property within the district, in accordance with the original classification and apportionment. Any assessment made under this section on any tract, parcel, or lot within the district which is computed at less than five dollars shall be fixed at the sum of five dollars.