Making Room for ADUs in Iowa

SF 592: Accessory Dwelling Units

While the latest housing stats report from Iowa REALTORS® shows a welcome increase in housing inventory across the state, Iowa, like most of the country, continues to face housing inventory challenges. 

This year, the legislature and housing advocacy groups have been examining ways to increase inventory and promote attainable housing in our state. Accessory dwelling units or ADUs are an up-and-coming way to address this challenge. 

Iowa REALTORS® was proud to be part of a broad coalition led by AARP to pass bipartisan legislation (SF592) to promote the construction of ADUs throughout our state, providing additional affordable and attainable housing solutions for Iowans. SF592 has been signed by Governor Kim Reynolds and takes effect on July 1, 2025. 

Below we answer common questions about this legislation and how it impacts housing in Iowa.

What is an Accessory Dwelling Unit?
An accessory dwelling unit is an additional residential dwelling unit located on the same lot as a single-family residence that is either attached to or detached from the single-family residence.

How does this legislation allow for the construction of more ADUs?
With the passage of SF592, cities and counties in Iowa must allow at least one ADU on the same lot as a single-family home. The ADU cannot exceed 1,000 square feet or 50% of the size of the primary residence, whichever is larger, and must adhere to applicable building regulations.

What type of requirements are there for ADUs?
Local governments cannot impose requirements on ADUs that are more restrictive than those applied to single-family residences. This includes aspects such as building height, setbacks, lot size, frontage, lot coverage, density, and aesthetic standards. Additionally, ADUs are not required to match the exterior design, roof pitch, or finishing materials of the primary residence. 

If a manufactured or mobile home is used as an ADU, it must be converted to real property by being placed on a permanent foundation and assessed for real estate taxes.

Can ADUs be used as rentals?
Regulations on the use of ADUs as rental properties cannot be more restrictive than existing state laws governing rentals, meaning an ADU can be used as a rental should the owner desire to do so.

Can any entities restrict the construction of ADUs?
An ADU can be prohibited or limited only to the extent that a state historic building code restriction, a deed restriction, or a rule of a common interest community, limits or prohibits the construction or use of an ADU. 

If you have any additional questions on SF592 and accessory dwelling units, please reach out to Director of Government ]Affairs Greta Haas.