Iowa Code Title IX. Local Government [Chs. 331-420] § 372.6. Council-manager-at-large form

2. a. The city council of a city governed by the council-manager-at-large form may adopt a resolution on its own motion, or shall adopt a resolution if a petition valid under section 362.4 is filed with the city clerk, proposing that the city be governed by a mayor elected by the people for a four-year term and four council members elected at large. After adoption of the resolution, the council shall direct the county commissioner of elections to put the proposal on the ballot for the next general election or the next regular city election, whichever occurs first. If the ballot proposal is approved, the city council shall adopt an ordinance meeting the requirements of paragraph “b”, and the ordinance is effective beginning with the next following regular city election.

b. The ordinance shall provide that the mayor is a member of the council and may vote on all matters before the council. The ordinance shall provide that the term of office of the mayor is four years and, after each regular city election, the mayor shall appoint a council member as mayor pro tem. The ordinance shall provide that the mayor is a member of the council for purposes of maintaining staggered terms on the council. A council member's term shall not be shortened or lengthened as a means of initially implementing the ordinance.

c. An ordinance adopted and approved under this subsection is not subject to repeal until the ordinance has been in effect for at least six years. The question of repeal of the ordinance is subject to the requirements of paragraph “a”.