Room Addition Permit in Milwaukee (2026)
Room Addition permit requirements, fees, and process for Milwaukee, WI. Find out if you need a permit and how to apply.
Room Addition permit requirements in Milwaukee, WI are conditional depending on project scope.
A Room Addition permit may be required depending on project scope in Milwaukee, WI. The local building department handles permit applications for Milwaukee. Below you will find the current thresholds, fees, and process for obtaining a room addition permit in Milwaukee.
Permit Fees
Contact the local building department at (414) 286-2543 for current fee information.
How to Get a Room Addition Permit in Milwaukee
Verify whether your project meets the permit threshold in Milwaukee: contact the local building department to confirm if your project requires a permit.
Prepare your permit application and plans. Contact the local building department at their official website for required documentation.
Submit your application in person at the local building department.
Milwaukee Department of Neighborhood Services (DNS)
Phone: (414) 286-2543 · Verified July 6, 2026 · Source
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 — Room Addition Requirements. Last verified April 6, 2026. View source