Iowa Admin. Code r. 821-7.5
If the United States Post Office provides official notice to the county registrar of commencement or termination of household mail delivery in a particular jurisdiction or area over which the registrar has authority to register voters and maintain the voter registration list, the county registrar may use that official notice to update or remove the mailing addresses on voter registration records affected by the notice. Mailing addresses may be added to or removed from the voter registration records based on the official notice from the United States Post Office. If a mailing address is added to or removed from a voter's registration record pursuant to this rule, a voter registration acknowledgment shall be mailed to the voter at the updated mailing or residential address on file. If the acknowledgment mailed to the updated address is returned as undeliverable by the United States Post Office, the voter's registration status shall remain unchanged, and the voter's registration record shall be restored to remove the update initiated pursuant to this rule.
Iowa Admin. Code r. 821-7.5