Iowa Code § 441.40

The clerk of the court shall likewise certify to the county treasurer the costs assessed by the court on any appeal from a board of review to the district court, in all cases where said costs are taxed against the board of review or any taxing body. Thereupon the county treasurer shall compute and apportion the said costs between the various taxing bodies participating in the proceeds of the collection of the taxes involved in any such appeal, and said treasurer shall so compute and apportion the various amounts which said taxing bodies are required to pay in proportion to the amount of taxes each of said taxing bodies is entitled to receive from the whole amount of taxes involved in each of such appeals. The said county treasurer shall deduct from the proceeds of all general taxes collected the amount of costs so computed and apportioned by the treasurer from the moneys due to each taxing body from general taxes collected. The amount so deducted shall be certified to each taxing body in lieu of moneys collected. Said county treasurer shall pay to the clerk of the district court the amount of said costs so computed, apportioned and collected by the treasurer in all cases now on file or hereafter filed in which said costs have not been paid.