Can I Build ADU in Des Moines, IA? (2026)
Find out if you can build a adu in Des Moines, IA. Rules, permit requirements, costs, and next steps.
Yes, ADUs are allowed in Des Moines, IA. California state law ensures by-right approval.
An Accessory Dwelling Unit (ADU) is a secondary housing unit on a residential lot — also called a granny flat, in-law suite, or backyard cottage. In Des Moines, IA, ADUs are permitted by right under state law, making them one of the most accessible ways to add housing on your property. ADUs can be detached, attached to the main home, or created by converting an existing garage or accessory structure.
ADU Rules in Des Moines
ADU Rules in Des Moines: Detached ADU max size: 900 sq ft. Attached ADU max size: 700. Setbacks: 3 ft side, 5 ft rear. Owner-occupancy: 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..
Costs & Fees
ADU permits in Des Moines: Total estimated permit cost: $800-$3,500 total permit fees. Contact the Des Moines Permit and Development Center for current fee schedule.
Timeline
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.
Next Steps
Next steps for building an ADU in Des Moines: 1. Review full ADU rules including size limits, setbacks, and parking. 2. Apply for an ADU permit through the Des Moines Permit and Development Center at https://dsm.city/departments/permit_and_development_center-division/pages/permits. 3. Hire a licensed contractor familiar with IA ADU requirements.
Des Moines Permit and Development Center
Phone: (515) 283-4200
Website: https://dsm.city/departments/permit_and_development_center-division
Online Permits: https://dsm.city/departments/permit_and_development_center-division/pages/permits
Frequently Asked Questions
Can I build an ADU (garage apartment or in-law suite) in Des Moines?
Yes. Des Moines's Zoning Ordinance (Chapter 134) allows ADUs in residential zones. Detached ADUs up to 900 sqft are permitted in rear yards. No owner-occupancy is required. One parking space is required per ADU. Des Moines has some of the lowest ADU permitting costs among major US cities — no impact fees and affordable plan review fees. Contact the Permit and Development Center at (515) 283-4200.
What is the Sherman Hill Historic District and how does it affect permits?
Sherman Hill is a Victorian-era residential neighborhood immediately west of the Iowa State Capitol — one of the best-preserved late 19th-century neighborhoods in Iowa. If your home is in the Sherman Hill Historic District, exterior changes (including additions, siding replacements, window changes, and ADU construction visible from the street) require a Certificate of Appropriateness from the Des Moines Historic Preservation Commission before you can obtain a building permit. Interior changes do not require historic review. Contact the Des Moines Community Development Department at (515) 283-4182.
Does MidAmerican Energy offer incentives for residential solar in Des Moines?
MidAmerican Energy (a Berkshire Hathaway Energy company) provides net metering for residential solar systems. Iowa does not have a state solar mandate, but MidAmerican has committed to 100% renewable energy for its customers — making them generally cooperative with solar interconnection. A Des Moines building permit and MidAmerican interconnection agreement are required before installing grid-tied solar. Contact MidAmerican Energy's Renewable Energy department or a licensed Iowa solar contractor.
What are the flood risks for Des Moines properties?
Des Moines has significant flood history — the 1993 and 2008 floods were catastrophic, covering portions of downtown and west Des Moines. Properties along the Des Moines River and Raccoon River corridors may be in FEMA-designated Special Flood Hazard Areas (SFHA) requiring flood insurance and elevated construction standards. Use FEMA's Flood Map Service Center (msc.fema.gov) to check your property's flood zone. Des Moines Water Works manages the water supply, and the city has invested in flood control infrastructure since 1993.
What permits do I need for a deck or fence in Des Moines?
Fences under 6 ft in side and rear yards do not require a permit. Fences in front yards or over 6 ft require a permit from the Des Moines Permit Center ($40-$150). All elevated decks (30+ inches from grade) require a building permit. Deck permits cost $75-$400 depending on size. Both can be applied for online at dsm.city. Inspections are required for deck construction.
Source: Des Moines Permit and Development Center — Building Regulations. Last verified April 6, 2026. View source