Iowa Code § 468.586
A county may assess to property within an urban drainage district the cost of a drainage improvement within the county and drainage facilities extending outside the county. A county is empowered to proceed and construct and to assess the cost of a drainage improvement within a district in the same manner as a city may proceed under chapter 384, subchapter IV, and the provisions of chapter 384, subchapter IV, apply to counties with respect to drainage improvements, the assessment of their costs and the issuance of bonds for the improvements. A county may contract for a drainage improvement within a district under this part pursuant to chapter 331, subchapter III, part 3.
Iowa Code § 468.586
85 Acts, ch 144, §1 89 Acts, ch 126, §2 2011 Acts, ch 25, §59; 2018 Acts, ch 1041, §127