48A.6  Disqualified electors.
  The following persons are disqualified from registering to vote and from voting:
  1.  A person who has been convicted of a felony as defined in section 701.7, or convicted of an offense classified as a felony under federal law. If the person’s rights are later restored by the governor, or by the president of the United States, the person may register to vote.
  2.  A person who is incompetent to vote. Certification by the clerk of the district court that any such person has been found no longer incompetent by a court shall qualify such person to again be an elector, subject to the other provisions of this chapter.
94 Acts, ch 1169, §7; 98 Acts, ch 1185, §2; 2002 Acts, ch 1134, §18, 115

Proceedings regarding competency to vote, see §222.16, 229.27, 633.556 
Restoration of rights by governor, see chapter 914