Iowa Code § 468.61
When one-half or more of all assessments for a drainage or levee district have been paid and it is ascertained that there will be a surplus in the district fund after all assessments have been paid, the board may refund to the owner of each tract of land, not more than fifty percent of the owner's proportionate part of such surplus. When all construction work has been completed and all cost paid, and all assessments have been paid in full, the board may refund, to the owner of each tract of land, the owner's proportionate part of any surplus funds except such portion of the surplus as the board considers should be retained for a sinking fund to pay future maintenance and repair costs.
Iowa Code § 468.61
89 Acts, ch 126, §2
Referred to in §468.57, 468.127