ADU Rules in Des Moines, IA (2026)
ADU rules, permit requirements, size limits, and fees for Des Moines, IA. Source-cited from official municipal code.
Whether ADUs are allowed in Des Moines, IA has not been confirmed — see the official source before proceeding.
Whether Des Moines, IA permits accessory dwelling units (ADUs) has not been confirmed from an official source. ADUs — also called granny flats, in-law units, or secondary suites — are secondary housing units on a single-family or multifamily lot. Contact the local building department at (515) 283-4200 to verify current ADU rules before proceeding, as regulations may have changed since this data was last reviewed.
ADU Size Limits
ADU Size Limits in Des Moines: Detached ADU: size varies by zoning — see official source (max height: varies — see official source). Attached ADU: size varies by zoning — see official source.
| Type | Max Size | Max Height |
|---|---|---|
| Detached ADU | See official source | See official source |
| Attached ADU | See official source | See official source |
Permit Fees
ADU Permit Fees in Des Moines: Plan check fee: Varies. Building permit fee: Varies. Impact fees: None. School fees: None or N/A. Total estimated permit cost: Varies.
| Fee Type | Amount |
|---|---|
| Plan Check | $100-$500 |
| Building Permit | Based on construction value — typically $700-$3,000 |
| Impact Fees | None |
| School Fees | None |
| Total Estimate | See official source |
Permit Timeline
Des Moines ADU Permit Timeline: Permit timeline has not been confirmed — contact the department for current processing times. Apply through the local building department online permit portal. Phone: (515) 283-4200.
Setback Requirements
ADU Setback Requirements in Des Moines: Front setback: follows zone standard. Side setback: no minimum. Rear setback: no minimum.
Parking Requirements
Parking Requirements: Parking requirements have not been confirmed — see official source.
Restrictions & Requirements
- ADU must comply with Des Moines Building Code habitability standards
- Detached ADU located in rear yard behind principal structure
- Must maintain zone setback requirements
- Sherman Hill Historic District and other historic overlays require HDC review
- Flood plain overlay along Des Moines River and Raccoon River corridors restricts construction
- Iowa tornado country — construction must meet wind-load and storm shelter requirements
How Many ADUs Are Allowed?
Number of ADUs Allowed in Des Moines: Single-family lots: not confirmed — see official source. Multifamily properties: not confirmed — see official source.
- Single-Family Lots
- 1 ADU per lot
- Multifamily Properties
- Accessory units on multifamily parcels subject to site plan review
Statewide Preemption
ADU Preemption
We could not confirm a statewide ADU preemption statute for Iowa.
View Iowa preemption detailsFrequently Asked Questions
Can I build an ADU in Des Moines?
Yes. Des Moines, IA allows accessory dwelling units. On a single-family lot you can build 1 ADU per lot.
How big can an ADU be in Des Moines?
The maximum size for a detached ADU in Des Moines is 900 square feet.
How long does it take to get an ADU permit in Des Moines?
The typical ADU permit timeline in Des Moines is Des Moines Permit and Development Center: ADU permits typically 3-6 weeks for plan review. Construction 2-7 months. Des Moines has a streamlined online permit portal.. Total estimated permit fees are $800-$3,500 total permit fees.
Do I need extra parking for an ADU in Des Moines?
Des Moines parking rules for ADUs: One parking space required per ADU. Des Moines's auto-dependent urban form means most parcels can accommodate on-site parking. Reduced parking requirements may apply in transit-corridor overlay zones near ART (Arterial Rapid Transit) routes.
Do I have to live on-site to have an ADU in Des Moines?
Owner-occupancy requirement in Des Moines: No owner-occupancy requirement under Des Moines Zoning Ordinance. Des Moines's investor-friendly housing market and relatively low property values make non-owner-occupied ADU rentals common.
Source: Des Moines Code of Ordinances Chapter 134 (Zoning); Des Moines Building Code. Last verified April 6, 2026. View source