Iowa ADU permit requirements
Last reviewed: June 20, 2026
Quick answer
Permitting an accessory dwelling unit (ADU) in Iowa means pulling a building permit from the local authority that issues it. Iowa has a statewide ADU law that sets baseline standards local agencies must follow. ArchPermit tracks 14 source-cited requirements (11 required, the rest conditional) for this jurisdiction. These requirements were last reviewed June 20, 2026; confirm the exact forms and fees with the local permitting authority.
Iowa has a statewide ADU law. This baseline reflects that law plus the universal new-dwelling deliverables. Your local city or county still administers the permit and may add its own forms and fees, so confirm the exact checklist with them.
Iowa's SF 592 (2025, effective July 1, 2025) requires every city and county to allow at least one ADU on a single-family lot. The local AHJ still issues zoning approval and building permits, and ADUs must meet the State Building Code (ch. 103A).
- Adopted building code compliancerequired
The ADU must comply with the residential building code adopted by the local jurisdiction; confirm the edition with the AHJ.
source · reviewed 2026-06-20 - Building cross-sectionsrequired
Cross-sections through the structure showing ceiling heights, wall/roof assemblies, insulation, and fire/sound-rated assemblies where required.
source · reviewed 2026-06-20 - Egress & life-safetyrequired
Emergency escape and rescue openings (egress windows), smoke and carbon-monoxide alarms, and required exits per the adopted residential code.
source · reviewed 2026-06-20 - Energy code compliancerequired
Energy-code compliance documentation for the conditioned space. Iowa: Iowa Residential Energy Code (per Iowa Code ch. 103A).
source · reviewed 2026-06-20 - Exterior elevationsrequired
Elevations of each affected building face showing height, exterior materials, and openings; existing vs. proposed where exterior changes occur.
source · reviewed 2026-06-20 - Floor plansrequired
Dimensioned floor plans of the ADU (and affected areas of the primary dwelling) showing rooms, uses, door/window locations, egress, and fixture/equipment locations.
source · reviewed 2026-06-20 - Foundation planrequired
Foundation plan with footing/stem-wall sizes and details (or a cited site-specific design), per the adopted residential code.
source · reviewed 2026-06-20 - Framing / structural plansrequired
Floor, wall, and roof framing showing member sizes, spans, spacing, connections, and lateral bracing; structural calculations where the framing is non-conventional.
source · reviewed 2026-06-20 - Local zoning / setback compliancerequiredverify locally
Compliance with the local jurisdiction's zoning: permitted use, setbacks, height, lot coverage, and any ADU-specific standards. These are set locally. Confirm with the permitting agency.
source · reviewed 2026-06-20 - Mechanical / plumbing / electricalrequired
HVAC, plumbing fixtures and lines, and electrical (panels, circuits, outlets, lighting, smoke/CO alarms) for the new unit.
source · reviewed 2026-06-20 - Site / plot plan (to scale)required
Scaled site plan showing property lines, setbacks, existing structures, the proposed ADU footprint with dimensions to property lines, driveways/parking, and utility locations.
source · reviewed 2026-06-20 - ADU size cap (greater of 1,000 sf or 50%)conditionalverify locally
An ADU may not exceed the greater of 1,000 sq ft or 50% of the single-family residence.
source · reviewed 2026-06-20 - At least one ADU on any single-family lotconditionalverify locally
Every city and county must permit ≥1 ADU on a lot with a single-family residence (SF 592).
source · reviewed 2026-06-20 - No owner-occupancy or added parking/feesconditionalverify locally
No owner-occupancy condition and no additional parking requirements or fees may be imposed on a lot with a single-family residence and an ADU.
source · reviewed 2026-06-20
Iowa ADU permit questions
- Do I need a permit to build an ADU in Iowa?
- Yes. An accessory dwelling unit (ADU) in Iowa requires a building permit, and Iowa has a statewide ADU law that sets baseline standards local agencies must follow. ArchPermit tracks 14 cited requirements for this jurisdiction (11 required, the rest conditional). Always confirm the exact forms, fees, and code edition with the local permitting authority that issues the permit.
- What does an ADU permit package require in Iowa?
- Core required items include: Adopted building code compliance; Building cross-sections; Egress & life-safety; Energy code compliance; Exterior elevations; Floor plans, plus 5 more. Each requirement links to its authoritative source, and nothing is permit-ready until an independent licensed professional reviews and seals it.