Wisconsin · Penalties if you skip one
What you can build without a permit in Wisconsin
By Mario Bailey Last checked · 14 official sources
Quick answer
Across the 2 Wisconsin jurisdictions we have verified, 3 of 20 project rules need no permit at all, 11 turn on a size or scope condition the jurisdiction publishes, and 6 require a permit regardless. Electrical work is where the answer most often comes with a published condition rather than a flat yes: 2 of the 2 jurisdictions that answer publish one.
How to read this page
"No permit" means the jurisdiction publishes that the work needs no building permit. "Depends" means it publishes a size, height, depth, cost or scope condition that decides the answer, quoted in its own words in the last column; the number beside it is the figure that condition turns on, and which side of the number is exempt is stated by the condition, not by us. Exempt from a building permit is not exempt from zoning, setbacks, height limits, flood rules, an HOA, or a separate electrical, plumbing or mechanical permit, and several of the conditions below say exactly that.
Electrical
All 2 make the electrical answer turn on a size or scope condition the jurisdiction publishes.
| Jurisdiction | Permit | Published figure | What the rule says |
|---|---|---|---|
| Madison | Depends | Madison requires an electrical permit for all electrical work except a short list of minor repairs, and the Development Services Center chart lists "Electrical Work, All" as Yes. | |
| Milwaukee | Depends | Milwaukee requires an electrical permit for essentially all household electrical work, pulled by a licensed electrician rather than by the homeowner. |
HVAC
All 2 make the HVAC answer turn on a size or scope condition the jurisdiction publishes.
| Jurisdiction | Permit | Published figure | What the rule says |
|---|---|---|---|
| Madison | Depends | Madison requires an HVAC permit for essentially all heating, ventilating and air conditioning work, with one narrow published exemption: no heating permit is needed to install electric baseboard or bathroom heaters used as auxiliary heat to supplement an existing system already sized for the space. | |
| Milwaukee | Depends | Milwaukee requires an HVAC permit for furnace and central air conditioning work: the Does It Need a Permit page answers "Yes" to both "Air conditioner" and "Furnace", the fee schedule prices heating units by BTU input and air conditioning and refrigeration units by ton, and DNS runs a dedicated 1&2 Family HVAC Checklist field inspection report that carries a permit number field and covers the furnace, gas line, venting, combustion air, condensate line, dedicated electrical breaker, the A/C condensing unit and the distribution ductwork. |
Patio
Madison and Milwaukee require no patio permit at all.
| Jurisdiction | Permit | Published figure | What the rule says |
|---|---|---|---|
| Madison | No permit | Madison publishes an explicit answer for patios in the Development Services Center "Do I Need a Permit?" chart: Patio, No, with Zoning at 608-266-4551 ext. 3 named as the contact. | |
| Milwaukee | No permit | An at-grade patio needs no building permit in Milwaukee. |
Plumbing
All 2 make the plumbing answer turn on a size or scope condition the jurisdiction publishes.
| Jurisdiction | Permit | Published figure | What the rule says |
|---|---|---|---|
| Madison | Depends | Madison requires a plumbing permit application to be filed before any plumbing work starts, with a stated exception: "A permit application is not required when minor repairs are made to part of an existing plumbing system." The Development Services Center chart lists "Plumbing - All" as Yes, along with "Water Heater - install" and "Water Softener - install". Applications must be signed by a person qualified as a licensed plumber registered with the Wisconsin Department of Safety and Professional Services, and the application with the correct inspection fee must be filed no later than three working days after work begins. | |
| Milwaukee | Depends | Milwaukee requires a plumbing permit for essentially all plumbing work, obtained from the Development Center, with one narrow exemption: replacing plumbing fixtures such as faucets, toilets, sinks, showers and tubs without altering the water supply and distribution, sanitary drainage or vent systems. |
Shed
All 2 make the shed answer turn on a size or scope condition the jurisdiction publishes, and the 2 that state a number all publish 150 sq ft.
| Jurisdiction | Permit | Published figure | What the rule says |
|---|---|---|---|
| Madison | Depends | 150 sq ft | shed or accessory building floor area; heated sheds and sheds within ten feet of dwelling units on the property need a permit at any size. |
| Milwaukee | Depends | 150 sq ft | detached tool or storage sheds located in the rear yard and at least three feet from the property lines. |
Deck
1 of 2 makes the deck answer turn on a size or scope condition the jurisdiction publishes. Madison requires a permit for deck work regardless of size.
| Jurisdiction | Permit | Published figure | What the rule says |
|---|---|---|---|
| Milwaukee | Depends | Building or replacing a deck or porch in Milwaukee requires plan review and a building permit, and the plans are checked against both the Wisconsin Uniform Dwelling Code and the city's building and zoning codes. | |
| Madison | Permit required | Madison requires a building permit to build a deck, with no size or height exemption; the Development Services Center chart lists "Deck - build" as "Yes". A site plan is required if the deck is over three feet high, along with construction drawings showing deck size, post locations, beam sizes and joist size and spacing. |
Fence
Madison requires no fence permit at all. Milwaukee requires a permit for fence work regardless of size.
| Jurisdiction | Permit | Published figure | What the rule says |
|---|---|---|---|
| Madison | No permit | These rows describe the rules of the City of Madison, a city of about 270,000 that runs its own Building Inspection Division inside the Department of Planning and Community and Economic Development; neighboring Dane County municipalities such as Fitchburg, Middleton, Monona, Sun Prairie and Verona issue their own permits and are not covered here. | |
| Milwaukee | Permit required | Milwaukee requires a fence permit for both new and replacement residential fences, with no size or height floor that exempts a fence from permitting; the Does It Need a Permit page answers "Yes" to both "Fence -- new" and "Fence -- replace", and fences are absent from the city's published list of home updates that do not need a permit. |
Pool
1 of 2 makes the pool answer turn on a size or scope condition the jurisdiction publishes. Madison requires a permit for pool work regardless of size.
| Jurisdiction | Permit | Published figure | What the rule says |
|---|---|---|---|
| Milwaukee | Depends | 3,965 gallons | pool at least 15 feet by 3 feet in size or holding 3,965 gallons. |
| Madison | Permit required | Madison requires a permit for a swimming pool and makes no distinction by size or depth: the Development Services Center chart lists "Swimming Pool" as Yes, routed to Building Inspection at 608-266-4551 ext. 2. |
Roof Replacement
1 of 2 makes the roof replacement answer turn on a size or scope condition the jurisdiction publishes. Madison requires a permit for roof replacement work regardless of size.
If the work is already built
Wisconsin runs a genuinely statewide residential building code, the Uniform Dwelling Code, covering one- and two-family dwellings built on or after June 1, 1980. A Wisconsin uniform building permit must be obtained before any on-site construction, including excavation for the structure, may begin.
Wisconsin penalties, the after-the-fact path, and what the statute actually says
The 20 answered rules come from 14 official sources, each linked from the permit page behind every jurisdiction name. See the full picture for the state on the Wisconsin permit requirements page, or the national view of which projects need a permit at all on Do you need a building permit?
This page compiles what each Wisconsin jurisdiction publishes, with a last checked date. It is not legal advice, and a project that is exempt from a building permit can still need zoning approval or a trade permit. Confirm with the office linked from the jurisdiction's page before you build.