Iowa Code § 655.5: Instrument of satisfaction.

When the judgment is paid in full, the mortgagee shall file with the clerk a satisfaction of judgment which shall release the mortgage underlying the action. A mortgagee who fails to file a satisfaction within thirty days of receiving a written request shall be subject to reasonable damages and a penalty of five hundred dollars plus reasonable attorney fees incurred by the aggrieved party, to be recovered in an action for the satisfaction by the party aggrieved.