Iowa Admin. Code r. 821-7.3
If a voter registration list maintenance notice is sent to the mailing address listed on a voter's registration record and the notice is returned to the county registrar as undeliverable by the United States Post Office, the county registrar shall leave the voter's status as active, inactive or pending, remove the mailing address from the voter's registration record, and send the notice by forwardable mail to the voter's residential address. If the notice sent to the residential address on the voter's registration record is returned as undeliverable by the United States Post Office, the county registrar shall make the voter's status inactive, and the voter shall be mailed a notice as required by Iowa Code section 48A.29, subsection 1. A voter registration list maintenance notice for purposes of this rule includes any notice sent pursuant to Iowa Code section 48A.27 or 48A.28.
Iowa Admin. Code r. 821-7.3