ADU (Accessory Dwelling Unit) Permit in Milwaukee (2026)
ADU (Accessory Dwelling Unit) permit requirements, fees, and process for Milwaukee, WI. Find out if you need a permit and how to apply.
Yes, a ADU (Accessory Dwelling Unit) permit is required in Milwaukee, WI.
A ADU (Accessory Dwelling Unit) permit is required in Milwaukee, WI. The Milwaukee Department of Neighborhood Services (DNS) handles permit applications for Milwaukee. Below you will find the current thresholds, fees, and process for obtaining a adu (accessory dwelling unit) permit in Milwaukee.
When Is a Permit Required?
When a ADU (Accessory Dwelling Unit) Permit Is Required in Milwaukee: All ADU construction
Permit Fees
ADU (Accessory Dwelling Unit) Permit Fees in Milwaukee: $1,000-$4,500. Estimated timeline: 4-8 weeks.
Estimated timeline: 4-8 weeks
How to Get a ADU (Accessory Dwelling Unit) Permit in Milwaukee
Verify whether your project meets the permit threshold in Milwaukee: All ADU construction.
Prepare your permit application and plans. Contact the Milwaukee Department of Neighborhood Services (DNS) at https://city.milwaukee.gov/DNS for required documentation.
Submit your application online at https://city.milwaukee.gov/DNS/Permits or in person at the Milwaukee Department of Neighborhood Services (DNS).
Pay the permit fee: $1,000-$4,500.
Wait for plan check approval. Estimated timeline: 4-8 weeks.
Schedule required inspections through https://city.milwaukee.gov/DNS/Inspections. All inspections must pass before project is finalized.
Important: Milwaukee DNS permit. Also requires Milwaukee rental housing license for occupied rental unit. Milwaukee rental license application at city.milwaukee.gov/DNS.
Milwaukee Department of Neighborhood Services (DNS)
Phone: (414) 286-2268
Website: https://city.milwaukee.gov/DNS
Online Permits: https://city.milwaukee.gov/DNS/Permits
Hours: Mon-Fri 7:45am-4:30pm
Frequently Asked Questions
What is a Polish Flat and how does it affect ADU rules in Milwaukee?
A Polish Flat is a distinctive Milwaukee architectural type — a two-story house where the main living floor is elevated above a lower-floor apartment, with the front foundation visible between the ground and the elevated porch. This type was developed by Milwaukee's Polish immigrant community in the early 1900s as a built-in ADU. Many Milwaukee properties already function as two-family homes because of this tradition. If your Polish Flat has a lower-floor unit, it may require proper permitting and a Milwaukee rental housing license to legally operate as a rental.
Can I rent out a room or my whole home short-term (Airbnb) in Milwaukee?
Yes. Milwaukee requires a Short-Term Rental License ($150/year) for rentals under 30 consecutive days. Wisconsin Act 59 of 2017 prevents Milwaukee from banning STRs of 7 or more consecutive days outright, though Milwaukee may impose licensing requirements, safety standards, and density limits. Wisconsin state sales tax (5%) applies to STR revenues. Contact Milwaukee DNS or the City Clerk for current licensing requirements.
Can I build an ADU (carriage house or in-law suite) in Milwaukee?
Yes. Milwaukee's Zoning Code allows detached ADUs (often called carriage houses) of up to 900 sqft in the rear yard of residential properties. One parking space is required unless you're near a transit corridor. No owner-occupancy requirement. A building permit from Milwaukee DNS is required, and occupied rental units need a Milwaukee rental housing license. Contact Milwaukee DNS at (414) 286-2268.
What is Wisconsin Act 59 and how does it affect Milwaukee STRs?
Wisconsin Act 59, enacted in 2017, partially preempts local short-term rental bans. It prohibits Wisconsin municipalities (including Milwaukee) from completely banning short-term rentals of 7 or more consecutive days in residential zones. Milwaukee can still regulate STRs through licensing, density limits, safety requirements, and fire code compliance — it just cannot impose an outright ban on 7-night-or-longer rentals. Rentals shorter than 7 nights retain more local regulatory flexibility.
What permits are needed to convert a Milwaukee basement into a legal apartment?
Converting a Milwaukee basement or lower-floor unit to a legal apartment requires a building permit from Milwaukee DNS for the construction/renovation work (electrical, plumbing, egress windows, ceiling height compliance), plus a Milwaukee Rental Housing License for the occupied unit. Minimum ceiling height for habitable space is typically 7 ft. Egress windows are required for basement bedrooms. Fire separation between units may be required. Contact Milwaukee DNS at (414) 286-2268 for a pre-application meeting.
Source: Milwaukee Building Code — ADU (Accessory Dwelling Unit) Requirements. Last verified April 6, 2026. View source