Iowa Code § 468.299
When an intercounty district has been finally established and original construction completed and final settlement made with the contractor, as provided by section 468.292, the treasurer of the county having the largest acreage of the district shall be the depository for all funds of the district and the treasurer of the other counties in which the district is situated shall periodically, at least annually, pay over all district funds received within said period to the treasurer of the county with the largest acreage, except that funds payable on improvement certificates or bonds shall be disbursed to the holders of the certificates or bonds by the treasurer of the county in which the land encumbered is located.
Iowa Code § 468.299
89 Acts, ch 126, §2