Iowa Code § 230.35: Releasing liens.

A lien obtained pursuant to an action to collect any claim arising under this chapter shall be released by the board of supervisors when the claim or claims on which the lien is based have been fully paid or compromised and settled by the board, or when the estate of which the real estate subject to the lien is a part has been probated and the proceeds allowable have been applied to the claim or claims on which the lien is based.