Key facts
| Place | Building permit line | Notes |
|---|---|---|
| Saint Paul, MN | Exempt at 200 sq ft or less | Zoning setbacks apply; electrical needs a trade permit |
| Pittsburgh, PA | Exempt at 200 sq ft or less | Accessory to a one or two family home; electrical wiring needs a permit |
| Colorado Springs and El Paso County (PPRBD) | Exempt at 200 sq ft or less, on grade | One story, detached |
| Oregon (ORSC) | Exempt at 200 sq ft and 15 ft high | Not in R327 wildfire hazard zones |
| Grand Rapids, MI | Under 200 sq ft: planning permit | 200 sq ft or more: building permit |
| Ann Arbor, MI | No building permit at 200 sq ft or less | Zoning compliance permit required |
| Rochester, NY | Under 144 sq ft: zoning certificate only | Rear yard, 15 ft max, one per parcel |
| Madison, WI | Permit if heated, over 150 sq ft or within 10 ft of a home | A sauna is heated, so a permit is needed |
Sources: Saint Paul DSI, When Is a Permit Required; Pittsburgh PLI, Work Not Requiring a Permit; Pikes Peak Regional Building Department; 2023 Oregon Residential Specialty Code, Chapter 1; Grand Rapids Accessory Structure Permit; Ann Arbor Zoning Compliance Permits; Rochester Residential Sheds guide (July 2026); Madison New Shed. Checked October 24, 2026.
Where the 200 square foot number comes from
The model residential code most states adopt exempts one-story detached accessory structures used as tool and storage sheds, playhouses and similar uses when the floor area is 200 square feet or less. Cities and states copy, tighten or loosen that line. Saint Paul's Department of Safety and Inspections uses it directly, as does Pittsburgh's Permits, Licenses and Inspections department for structures accessory to a one or two family home. Pikes Peak Regional Building Department, which covers Colorado Springs and El Paso County, adds that the structure must be supported on grade. Oregon's state code adds a 15 foot height cap.
The exemption covers the building, not the heater
An electric sauna heater usually needs a dedicated 240 volt circuit. That is electrical work, and it needs its own permit even when the structure is exempt. Saint Paul says work on electrical systems requires trade permits; Pittsburgh lists electric wiring among work that is not ordinary repair. Budget for the electrical permit and inspection regardless of the sauna's size. Our breaker and wire size guide covers what the circuit typically involves.
Places that draw a different line
Rochester, New York, says sheds under 144 square feet need only a Certificate of Zoning Compliance, must sit in the rear yard, may not exceed 15 feet in height, and that only one storage structure is allowed per parcel. Madison, Wisconsin, requires a permit for any shed or accessory building that is over 150 square feet, heated, or less than ten feet from a dwelling on the same lot, and says prefab sheds moved onto the lot need one too. Because a sauna is heated, Madison's rule catches even the smallest model. Oregon withholds its exemption entirely for structures in wildfire hazard zones covered by Section R327.
Zoning still applies
An exemption from a building permit is not an exemption from zoning. Saint Paul says exempt accessory structures must comply with setbacks and lot coverage. Pittsburgh says all exempt work must comply with the zoning code and that exterior work in a historic district needs zoning review. Ann Arbor requires a zoning compliance permit for sheds, gazebos and similar structures of 200 square feet or less, and Grand Rapids routes structures under 200 square feet to a planning permit. Madison caps the total footprint of all accessory buildings at 1,000 square feet and requires three feet of clearance from the house and other structures.
Is a sauna a shed?
Codes describe the exemption in terms of sheds, playhouses and similar uses. A sauna has a heater and people sit in it at high temperature, so some building officials treat it differently from storage. The safest path is a short email to your building department with the sauna's footprint, height and heater specs before you order. Ask whether the exemption applies, whether a zoning permit is needed and which electrical permit covers the heater circuit.
Worked example: a 7 by 7 foot cube sauna in two cities
A 7 by 7 foot outdoor cube sauna has a 49 square foot footprint. In Saint Paul, it needs no building permit if it meets zoning setbacks and lot coverage, but the heater circuit needs an electrical permit pulled by the homesteader or a city licensed contractor. In Madison, the same sauna needs a shed permit because it is heated, plus the electrical permit, and it must sit at least three feet from the house.
Related guides
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- Sauna and cold plunge permits in Des Moines, Wichita, Oklahoma City and Indianapolis
- What should a barrel sauna sit on?
- What does it cost to install an outdoor sauna?
- Backyard sauna permits in Washington
- Backyard sauna permits in Oregon and Portland
- Sauna heater breaker and wire size
- Can you wire your own sauna heater? Homeowner permit rules
- Backyard sauna permits in Houston, Sacramento, Phoenix, Sparks and San Antonio
Frequently asked questions
Does a backyard sauna under 200 square feet need a building permit?
Often not. Many codes exempt one-story detached accessory structures of 200 square feet or less, including Saint Paul, Pittsburgh, Pikes Peak Regional Building Department and Oregon's state code. But some cities draw the line elsewhere, such as Rochester at 144 square feet and Madison, which requires a permit for any heated accessory building.
Does the heater circuit need a permit even if the sauna is exempt?
Yes, almost everywhere. The building exemption covers the structure, not the 240 volt heater circuit. Saint Paul and Pittsburgh both state that electrical work needs its own permit.
Why does Madison require a permit for a small sauna?
Madison requires a permit for any shed or accessory building that is heated, over 150 square feet, or less than ten feet from a dwelling. A sauna is heated by design.
Does Oregon's 200 square foot exemption apply everywhere in the state?
No. The Oregon Residential Specialty Code withholds the exemption for structures in wildfire hazard zones under Section R327, and it also caps height at 15 feet.
Do exempt saunas still have to meet zoning?
Yes. Saint Paul, Pittsburgh and Ann Arbor all say exempt structures must meet zoning setbacks and lot coverage, and Ann Arbor requires a zoning compliance permit for structures of 200 square feet or less.
Is a sauna a shed under these rules?
Codes list sheds, playhouses and similar uses. A sauna has a heater and is used by people, so some officials classify it differently. Ask your building department before ordering.
What size are most barrel and cube saunas?
Most backyard barrel and cube saunas have footprints well under 200 square feet, which is why the exemption usually matters more than the sauna's interior size.
Keep reading
Browse our saunas collection, see all guides, or ask us a question about your project.