What Permits Do You Need to Finish a Basement in Wisconsin?
Complete guide to basement finishing permits in Wisconsin, including building, electrical, plumbing, and HVAC requirements, egress window rules, and inspection steps.
Yes, you typically need a permit. To finish a basement in most Wisconsin municipalities, you need Remodeling Permit, Electrical Permit, Plumbing Permit, and HVAC/Mechanical Permit. Here's exactly what's required.
Permits Required
The following permits are typically required to finish a basement in Wisconsin. Actual requirements vary by municipality.
Remodeling Permit
Required for interior structural alterations, major renovations, and remodeling projects in existing buildings. Covers changes to load-bearing walls, basement finishing with egress, bathroom additions, and any work that alters the building's structural integrity under Wisconsin's Uniform Dwelling Code.
Inspection required after work is completed.
Electrical Permit
Required for all electrical installations, alterations, and repairs in Wisconsin. The state adopts the National Electrical Code (NEC) with Wisconsin-specific amendments under SPS 316. All electrical work on residential dwellings must be performed by a licensed master or journeyman electrician, or by a homeowner on their own single-family residence.
Inspection required after work is completed.
Plumbing Permit
Required for all plumbing installations, alterations, and repairs in Wisconsin. The state's plumbing code (SPS 381–387) is among the most detailed in the nation. All plumbing work must be performed by a Wisconsin licensed master or journeyman plumber, with very limited homeowner exemptions.
Inspection required after work is completed.
HVAC/Mechanical Permit
Required for installing, replacing, or significantly modifying heating, ventilation, and air conditioning systems in Wisconsin. Covers furnaces, boilers, air conditioners, heat pumps, ductwork, and ventilation systems. Residential HVAC falls under the UDC; commercial systems under SPS 363–364. Wisconsin requires HVAC credentials through DSPS for most installations.
Inspection required after work is completed.
Where to Apply
Permit requirements, fees, and processing times vary by municipality. Check the specific requirements for your location:
Browse all jurisdictions →Exemptions & Special Cases
In some circumstances, a permit may not be required. Common exemptions include:
- Remodeling Permit: Cosmetic updates: painting, flooring, countertops
- Remodeling Permit: Replacing cabinets or fixtures without moving plumbing
- Electrical Permit: Replacing a light switch, outlet, or light fixture in kind
- Electrical Permit: Replacing a plug-in appliance
- Plumbing Permit: Replacing a faucet or showerhead
- Plumbing Permit: Clearing a drain clog
- HVAC/Mechanical Permit: Replacing filters, thermostats, or humidifiers
- HVAC/Mechanical Permit: Portable space heaters and window AC units
Exemptions vary by municipality. Always confirm with your local building department before starting work without a permit.
Frequently Asked Questions
Do I need a permit to finish my basement in Wisconsin?
Yes. Finishing a basement in Wisconsin requires a building permit in virtually every municipality. Work involving framing, electrical, plumbing, HVAC ductwork, or egress windows must be inspected under the Uniform Dwelling Code. If you are adding a bedroom, you must install an egress window meeting minimum size requirements (5.7 sq ft net clear opening).
What are the egress window requirements for a finished basement in Wisconsin?
Wisconsin requires at least one egress window in every finished basement bedroom. The window must have a minimum net clear opening of 5.7 square feet, be at least 20 inches wide and 24 inches tall, and the sill height cannot exceed 44 inches from the floor. If you are using a window well, it must be at least 9 square feet with a minimum width of 36 inches.
How much does it cost to get permits for a basement finish in Wisconsin?
Total permit costs for a basement finish in Wisconsin typically range from $300 to $1,200, depending on scope and municipality. This includes a building permit ($150–$600), electrical permit ($50–$200), plumbing permit ($50–$150 if adding a bathroom), and HVAC permit ($50–$200 if modifying ductwork). Cities like Milwaukee and Madison are on the higher end.
Building in multiple cities?
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