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SF 592 Iowa Senate · 2025-2026 Regular Session

A bill for an act relating to county and city regulation of accessory dwelling units.

This bill mandates that counties and cities in Iowa must allow at least one accessory dwelling unit (ADU) on lots with single-family residences. It directly affects property owners by standardizing and simplifying the process of building ADUs, and local governments by limiting their regulatory authority. The legislation sets statewide parameters, such as allowing ADUs up to 1,000 square feet or 50% of the main house, whichever is larger. It prohibits local ordinances from imposing overly restrictive rules on aspects like design, parking, owner-occupancy, or separate utility connections. Furthermore, it requires local governments to approve compliant ADU permits without discretionary review, following the same timeline as single-family home permits.
Issues: ✓ HousingSupports HousingBill mandates ADUs on single-family lots, increasing housing supply and supporting affordable housing development.90% confidence
Bill status signed all 5 stages cleared
Introduction
Mar 2025
Committee Review
Mar 2025
Senate Passage
Mar 2025
House Passage
Apr 2025
Signed into Law
May 2025
Introduced Mar 10, 2025 Signed May 1, 2025
Maddy AI version diff · 3 comparisons

What changed between versions

Enrolled → Enrolled with Governor's Action · 7 edits · May 1, 2025
MODERATE
This bill amends Iowa state law to require counties and cities to allow at least one accessory dwelling unit (ADU) per single-family home lot, with specific limits on size and restrictions on what local governments can require. The changes standardize ADU regulations across the state to promote housing availability while preserving certain local controls for historic districts and common interest communities.
Scope change
The bill expands state authority over local ADU regulations by mandating minimum allowances and prohibiting certain restrictive local requirements that were previously permitted.
REQUIREMENT

Requires counties and cities to allow a minimum of one ADU per single-family home lot, with size limits of 1,000 square feet or 50% of the main residence size, whichever is larger.

Prohibits local governments from requiring ADUs to match the main home's exterior design, roof pitch, or finishing materials.

Eliminates local requirements for additional parking or fees in lieu of parking for ADUs.

Prohibits restrictions on ADU occupancy based on familial relationships, income, or age.

Requires ADU permits to be processed within the same timeline as single-family residence permits without discretionary review.

DEFINITION

Defines ADU as attached or detached residential units on the same lot as a single-family residence, including detached garages.

ENFORCEMENT

Makes conflicting local ADU regulations void and requires written explanations with remedies for any permit denials.

Floor votes · Senate Mar 25, 2025 · House Apr 8, 2025

How they voted

50–0
Passed · 1 other
Total votes 51
Mar 25, 2025
D Democratic16
15 Yea 1
93% Yea
R Republican35
35 Yea
100% Yea
Vote distribution
All Yea All Nay Mixed No data
Full legislative history

Actions timeline

Total actions
14
Key actions
4
Committee
1
May 1, 2025
Signed into law
Signed by Governor.
upper
Apr 8, 2025
Lower · Passed
Passed House, yeas 89, nays 7.
lower
Mar 25, 2025
Upper · Passed
Passed Senate, yeas 49, nays 0.
upper
Mar 10, 2025
Upper · Passed
Committee report, approving bill.
upper
Mar 10, 2025
Introduced
Introduced, placed on calendar.
upper
0 primary · 0 co-sponsors

Sponsors

No sponsor information available.