PermitNotebook / Guides
Do you need a building permit?
By Mario Bailey Last checked
It depends on where you live and what you are building, and that is not a dodge: across the 1834 local rules we have verified in 169 US localities, 50% of project scenarios require a permit outright, 45% depend on the project's size or scope, and only a small remainder are permit-free. The table below shows where each common project usually lands, and the threshold that most often decides it.
The short answer, by project type
Counted from every locality we cover. "Most common threshold" is the figure that appears most often in our verified rows; your locality can differ, so follow the link to its exact rule.
| Project | Across our localities | Most common threshold | Details |
|---|---|---|---|
| Bathroom Remodel | Depends on size or scope (1 of 48 outright) | $40,000 (2 localities) | By state |
| Deck | Varies widely (86 of 169 outright) | 200 sq ft (23 localities) | By state |
| Electrical | Varies widely (118 of 169 outright) | 5 outlets, switches, receptacles or fixtures (1 locality) | By state |
| EV Charger | Usually required (38 of 48 outright) | 5 kilowatts (1 locality) | By state |
| Fence | Depends on size or scope (45 of 169 outright) | 7 feet in height (18 localities) | By state |
| HVAC | Usually required (123 of 169 outright) | 10 lbs refrigerant (1 locality) | By state |
| Patio | Depends on size or scope (33 of 169 outright) | 200 sq ft (9 localities) | By state |
| Plumbing | Varies widely (114 of 169 outright) | $2,500 (1 locality) | By state |
| Pool | Depends on size or scope (66 of 169 outright) | 24 inches of water depth (20 localities) | By state |
| Roof Replacement | Depends on size or scope (67 of 169 outright) | $7,500 (8 localities) | By state |
| Shed | Depends on size or scope (38 of 169 outright) | 200 sq ft (51 localities) | By state |
| Solar | Usually required (159 of 169 outright) | 3.5 lbs per sq ft (2 localities) | By state |
| Water Heater | Varies widely (30 of 48 outright) | No single number | By state |
Why the answer is local
Building codes start from statewide or model codes, but the permit trigger, the exemption sizes, and the process belong to your county or city. The same backyard shed can be permit-free in one county and require a full application one county over. That is why every rule on this site is recorded per locality, with the official source it came from, instead of as one national answer.
Watch for two local wrinkles our data keeps turning up: a county rule often does not apply inside an incorporated city that runs its own building department, and some projects that skip the building permit still need a different approval, like a zoning review for a fence line or an electrical permit for the wiring inside an otherwise exempt project.
Thresholds: the numbers that decide it
Most "do I need a permit" answers are really threshold questions: a square footage, a height, or a depth on one side of which no permit is needed. The catch is that the popular number is not the universal number. Sheds are the classic case: our verified shed rows alone carry 20 different thresholds (100 sq ft, 12 feet in any dimension, 120 sq ft, 120 sq ft of floor area, 120 sq ft of projected roof area, 144 sq ft, 150 sq ft, 150 sq ft of floor area, 200 sq ft, 25 sq ft, 256 sq ft, 36 sq ft, 400 sq ft, 480 sq ft, 50 sq ft, 600 sq ft, 65 sq ft, 68 sq ft, 75 sq ft, 81 sq ft). Fence rules spread the same way: we have verified 26 different fence height triggers ($7,500, 1 ft, 2 feet in height above average grade, 24 inches in height, 25 percent of fence area, 3 feet, 3 feet in height, 3 ft, 30 feet from right-of-way, 4 feet in height, 4 ft, 42 inches in height, 5 ft, 50 percent, 50 percent of existing fence replaced, 50 percent of fence length, 6 feet, 6 feet in height, 6 ft, 7 feet, 7 feet in height, 7 ft, 8 feet, 8 feet in height, 8 ft, 9 feet in height), so a fence that is exempt in one city needs a permit two towns over.
Every permit page on this site states its locality's threshold neutrally, with the official source, and the diagram on pages with a drawable threshold shows exactly what is being measured.
For the exemption side of the question, each state page below lists what its jurisdictions publish as needing no permit, and the conditions that decide the rest, in the offices' own words:
What happens if you skip the permit
Unpermitted work surfaces at the worst times: a sale, an insurance claim, a complaint, or a failed inspection on a later project. Consequences and the path back to compliance are set by state and local law, so we research them state by state, with statutes cited. If you are already in this situation, start with your state's guide:
- Virginia
- Maryland
- New Jersey
- Illinois
- Massachusetts
- Pennsylvania
- Florida
- Washington
- Texas
- Colorado
- Tennessee
- Georgia
- Arizona
- California
- Nevada
- North Carolina
- Ohio
- Minnesota
- New York
- Michigan
- Indiana
- Wisconsin
- South Carolina
- Missouri
- Oregon
- Louisiana
- Oklahoma
- Delaware
- Hawaii
- Nebraska
- Kentucky
- Kansas
- Idaho
- Iowa
- New Mexico
- Rhode Island
- Utah
- Arkansas
- Alabama
- Alaska
- South Dakota
More states are being researched; each page publishes only statute-cited facts.
Get your locality's answer in about two minutes
Pick your state and locality, check off what your project involves, and get the verified requirements, thresholds, fee notes, and office links for each item, assembled only from rules a person verified against official sources.