2026-09-10 · Iowa · Legislation

Iowa took the ADU decision away from its cities and counties in 2025. It did not take it away from associations. Senate File 592 requires every Iowa city and county to allow at least one accessory dwelling unit on the same lot as a single-family residence — and in the same breath preserves any deed restriction or association rule that prohibits one. Signed May 1, 2025, effective July 1, 2025.¹

What the state took off the table

The mandate is unusually detailed about what a local government may no longer do. An ADU must satisfy chapter 103A building regulations and may not exceed 1,000 square feet or 50% of the size of the single-family residence, whichever is larger. Within that envelope, a city or county may not impose any placement or appearance requirement stricter than the one it applies to the main house — the statute names maximum building heights, minimum setbacks, minimum lot sizes, minimum building frontages, maximum lot coverages, density requirements, and “aesthetic or architectural standards.”²

Nor may a local government require the ADU to match the main house's exterior design, roof pitch, or finishing materials. Also prohibited: additional parking or a fee in lieu; owner-occupancy requirements; familial, marital, employment-relationship, income, or age restrictions on either unit; separate utility lines, unless separate metering is otherwise impossible; a different impact-fee structure; and street or sidewalk improvements beyond those required of the house itself.

Permits must be approved without discretionary review or hearing, on the same timeline as a single-family residence, and a denial must be in writing stating the remedy.

The sentence that matters to an association

It sits at Iowa Code § 331.301(29)(a)(3) for counties and § 364.3(23)(a)(3) for cities. An ADU “shall 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, as defined in section 499C.1, limits or prohibits the construction or use of an accessory dwelling unit.”

The same sentence runs in the other direction too. A local government may not make its ADU regulation “more restrictive when applied to a common interest community than when applied to a single family residence.” A city cannot single out covenanted neighbourhoods for tougher treatment.

A citation note worth carrying. SF 592 enacted these as § 331.301(27) and § 364.3(20). The Code editor renumbered them to (29) and (23) in Code 2026. Anything citing the older subsection numbers is citing the same law under a stale address.

1. SF 592 bill history, Iowa General Assembly (2025 Iowa Acts ch. 38) ↩
2. SF 592, enrolled text (PDF), Iowa General Assembly ↩
3. Iowa Code ch. 364 — § 364.3(23) as codified (city limitation of powers) ↩
4. Iowa Code ch. 499C — § 499C.1 definitions, including the rule/expired-covenant limit ↩