You need a permit for a shed when it exceeds 200 square feet of floor area under the International Residential Code that most U.S. jurisdictions follow. Smaller sheds can still require one if they’re too tall, sit on a permanent foundation, include electrical or plumbing work, or stand inside a mapped flood zone. And a shed that doesn’t need a building permit still has to obey local zoning rules about where it can go.
The 200-Square-Foot Threshold
The IRC exempts one-story detached accessory structures from building permits when the floor area is 200 square feet or less. That’s the source of the common assumption that a small shed is always permit-free. Your local jurisdiction may have adopted a different number, though. Some set the cutoff at 120 square feet, others at 100, and a few are more generous. The only threshold that matters is the one your city or county actually enforces.
Height is a separate limit. Many jurisdictions cap permit-exempt accessory structures at 10 to 15 feet. A shed under 200 square feet but above the local height limit still needs a permit. Roof pitch matters here: a steep roof on a small footprint can push the total height past the threshold even when the walls themselves are short.
Utilities and Permanent Foundations
Running electricity, plumbing, or gas to a shed almost always requires a permit no matter how small the shed is. These are typically separate permits from the building permit. Wiring for lights and outlets needs an electrical permit; a sink or toilet needs a plumbing permit. The inspections exist because faulty wiring and improper plumbing connections are real safety hazards.
Foundation type can also pull an otherwise exempt shed into permit territory. A shed resting on concrete blocks, gravel, or wood skids is generally treated as temporary. Pour a concrete slab or dig frost-proof footings and you’ve built a permanent foundation, which most jurisdictions require a permit for even when the shed sitting on it is small.
Flood Zones Change the Rules
If any part of your property falls inside a Special Flood Hazard Area, federal rules tied to the National Flood Insurance Program apply, and accessory structures are not exempt from them just because they’re small.1FEMA.gov. Floodplain Management Requirements for Agricultural and Accessory Structures
In most flood zones (A zones), FEMA treats an accessory structure as “small” if it’s no larger than a one-story two-car garage. In coastal high-hazard V zones, the limit drops to 100 square feet. Whatever the size, the shed must be anchored against flotation and lateral movement, portions below the base flood elevation must use flood-resistant materials, and mechanical and electrical equipment has to sit above the base flood elevation or be designed to handle submersion.2FEMA.gov. Floodplain Management Requirements for Agricultural Structures and Accessory Structures – FEMA P-2140
Your community’s floodplain administrator, usually in the planning or building department, issues the required floodplain development permit. Skipping it doesn’t only put your shed at risk; it can jeopardize your community’s participation in the NFIP, which affects every property owner’s access to flood insurance.3FEMA.gov. FEMA Policy 104-008-03 – Floodplain Management Agricultural Structures Policy
Zoning Rules Apply Even When No Permit Is Required
A permit-exempt shed still has to follow local zoning. Four rules do most of the work.
Setbacks dictate how far the shed must sit from property lines, your house, and public rights-of-way. Rear and side setbacks of five to ten feet are common but vary by zoning district. Corner lots often have stricter rules because two sides face a street.
Easements are strips of your land that someone else, usually a utility, has the right to access. Check your deed or a survey before picking a spot. Building a shed on an easement can lead to forced removal at your expense when the utility needs to dig up a line.
Lot coverage limits cap how much of your lot can be covered by structures and paved surfaces, expressed as a percentage. Your house, driveway, patio, and any existing outbuildings all count. A shed that pushes you over the cap triggers a zoning violation even if the shed itself didn’t need a building permit. Your planning department can tell you what percentage applies and how close you already are.
Fire separation. The IRC requires accessory buildings to stay at least five feet from the property line. Sheds closer than that must have the wall facing the line built as a one-hour fire-resistance-rated assembly, with limits on windows, doors, and roof overhangs. Small sheds that fall under the 200-square-foot permit exemption are also exempt from fire separation rules, but anything larger has to comply. The simplest approach is to keep the shed five feet off every property line and avoid the fire-rated construction requirements entirely.
HOA Approval Is a Separate Track
If your community has a homeowners’ association, a permit from your city or county does not satisfy the HOA. These are two independent approval processes. HOAs often restrict shed size, placement, roofing material, exterior color, and architectural style. Some prohibit sheds outright. Read the covenants, conditions, and restrictions before buying materials, and submit an architectural review application if one is required. Tearing down a finished shed because it violates HOA rules is a much more expensive mistake than waiting a few weeks for approval.
How to Confirm What Your Jurisdiction Requires
Start with your city or county’s building or planning department. Most have a website section covering building permits, accessory structures, or zoning. Search for “shed permit,” “accessory structure,” or “detached building.” If the jurisdiction has adopted the IRC, the 200-square-foot exemption is a reasonable starting assumption, but always confirm the local version.
When the website isn’t clear, call. Useful questions:
- What’s the maximum floor area for a permit-exempt shed?
- What’s the maximum height for an exempt accessory structure?
- How far must the shed sit from property lines, the house, and the street?
- What percentage of the lot can be covered, and how much is already used?
- Does the proposed location fall in a Special Flood Hazard Area?
- Does a permanent foundation trigger additional requirements?
A short phone call can save weeks of rework. Building department staff answer these questions constantly and can often tell you on the spot whether your project needs a permit.
What Happens If You Build Without One
The first consequence is usually a stop-work order. A building inspector who spots unpermitted work can halt the project until you obtain the proper permit. Everything stops, including any contractor you’re paying by the day.
Fines follow, and many jurisdictions increase them for each day the violation goes uncorrected. An after-the-fact permit typically costs double or more what the original would have cost. You may also have to open up finished walls or foundations so an inspector can verify the work meets code, adding labor costs on top of the penalties.
If the shed violates setbacks, height limits, or other zoning rules in a way that can’t be corrected, the jurisdiction can order you to move or demolish it at your own expense. That’s the outcome most people don’t account for when they decide to skip the permit.
Problems also surface at sale. Most states require sellers to disclose known unpermitted work. Lenders may refuse to approve a mortgage on a property with code violations, shrinking your buyer pool to cash offers, and buyers who are willing to proceed will typically ask for a price reduction. Homeowner’s insurance is a separate risk: insurers can deny claims for damage related to unpermitted construction, and some will raise premiums or cancel coverage once they learn of the violation.