The Simple Rule — When You Need a Permit
The rule is consistent across almost all US jurisdictions: if your project changes the structure, the use, or any of the major systems (electrical, plumbing, mechanical, gas) of a building, you almost certainly need a building permit.
Cosmetic changes — painting, flooring, cabinet swaps, appliance replacements in the same location — typically do not require permits. The moment you move a wall, run new wiring, relocate plumbing, or expand the footprint, a permit is required.
Projects That REQUIRE a Permit
Any new habitable structure requires full permitting — structural, electrical, plumbing, mechanical, and fire.
Any expansion of the home footprint requires a building permit plus trade permits for each discipline involved.
Change-of-use permits required; plus all trade permits. California requires ADU permit approval within 60 days.
Load-bearing wall changes require engineering review and a structural permit in all jurisdictions.
All work on the main electrical service requires an electrical permit and inspection. No exceptions.
Running new circuits or outlets requires an electrical permit. Replacing existing wiring in kind usually does not.
New supply lines, drain lines, or fixture locations require a plumbing permit. Fixture swaps in existing locations typically do not.
New HVAC systems and ductwork require a mechanical permit. Thermostat replacement does not.
Attached decks or any deck over 30 inches from grade require a permit in most cities. Freeground-level patios often exempt.
Any permanent structure over 200 sq ft (or with plumbing/electrical) requires a permit.
Changing roofline pitch or adding dormers requires a permit. Like-for-like shingle replacement often does not.
Creating new openings in exterior or structural walls requires a permit. Replacing windows in existing openings often does not.
All in-ground pools require permits. Above-ground pools may be exempt in some cities if below a size threshold.
Any modification to or work on the foundation requires a permit without exception.
Free Permit Calculator
Estimate your permit cost by city and project type
Instant estimate — base fee, plan review, trade permits, surcharges
Projects That Usually Do NOT Require a Permit
Always verify with your local building department — exemptions vary by city.
No structural or system changes involved.
Like-for-like floor replacement in same location.
No plumbing or electrical relocation required.
Unless plumbing is being relocated.
Same location, same fuel type, no new connections.
No structural changes to the roof deck or framing.
Replacing windows without changing opening size.
Sheds under 200 sq ft with no utilities in most cities.
Fences under 6 ft in most cities; always verify locally.
Same location, same connections, no new plumbing lines.
What Happens If You Build Without a Permit?
Skipping a required permit is one of the most expensive mistakes a homeowner can make. The consequences extend well beyond construction — they follow the property for its entire lifespan.
City can halt all construction immediately. Work must stop until permits are obtained — even if 80 percent complete.
Fines typically run $200 to $5,000. Many cities charge double or triple the original permit fee as an after-the-fact penalty.
In severe cases, cities can require the unpermitted structure to be demolished at the homeowner's expense.
Buyer inspections flag unpermitted work. Lenders may refuse financing. Title companies can block closing until resolved.
Homeowners insurance can deny claims for damage involving unpermitted work — even if the damage is unrelated to the unpermitted area.
If someone is injured in or near unpermitted construction, the homeowner carries full liability without the protection of code-compliant inspections.
Related Permit Tools and Guides
Free — all project types, all US cities
→National Permit Cost GuideAverage costs by project type and state
→California Permit GuideLA, SF, San Diego permit costs
→Texas Permit GuideHouston, Dallas, Austin permit costs
→Permit Process StepsHow to apply and what to expect
→Bid AnalyzerIs your contractor quote reasonable?
→Frequently Asked Questions
Do I need a permit to build a house?
Yes. Building a new house requires a full set of permits in every jurisdiction in the United States — including a building permit, electrical permit, plumbing permit, and mechanical (HVAC) permit at minimum. In most cities, you also need zoning approval before applying for building permits to confirm the project meets local setback, height, and use requirements. There are no US jurisdictions that allow new residential construction without permits.
Do I need a permit to add a room to my house?
Yes. Any room addition that expands the footprint of the home requires a building permit plus trade permits for each discipline involved (electrical, plumbing, HVAC). The permitting process for a room addition typically takes 2 to 8 weeks. Permit costs for a 500 sq ft room addition range from $500 in affordable states to $5,000 or more in California and New York.
Do I need a permit to remodel my kitchen or bathroom?
It depends on the scope. A cosmetic remodel — new cabinets, countertops, flooring, paint — typically does not require a permit. A functional remodel that moves plumbing lines, adds or relocates electrical circuits, or changes ventilation requires a permit. Most kitchen and bathroom remodels involve some plumbing and electrical work, which means most require permits. Your contractor should be able to tell you exactly which permits apply to your specific project.
What happens if you build without a permit?
Building without a required permit creates serious legal and financial consequences. The city may issue a stop-work order halting all construction. You can face fines of $200 to $5,000 plus double or triple permit fees as penalties. Unpermitted structures create problems when selling the property — buyers, lenders, and title companies all flag unpermitted work. Homeowners insurance can deny claims involving unpermitted construction. In severe cases, the city can require demolition at your expense.
Can I get a permit after work is already done?
Yes — this is called an after-the-fact or retroactive permit. Most cities allow it but charge significantly higher fees, typically 1.5 to 3 times the standard permit cost. You may also be required to open walls, ceilings, or floors to expose the work for inspection. Some cities are more lenient than others. If unpermitted work was discovered during a home sale, an after-the-fact permit is often the required path to resolution. Contact your local building department as soon as possible rather than waiting.
Who pulls the building permit — me or my contractor?
In most cases, your licensed general contractor pulls the building permit as part of their service. Licensed trade contractors (electricians, plumbers, HVAC technicians) are required to pull their own trade permits in most states. You as the homeowner can pull an owner-builder permit for work on your own primary residence, but you take on legal responsibility for code compliance. Always ask your contractor for the permit number before construction starts — you can verify it is valid by calling your local building department.
Know what you need — then get the cost
Calculate Your Permit Cost in Seconds
Select your city and project type for a free instant estimate of all permit fees — base permit, plan review, trade permits, and surcharges.
Start My Permit Calculator →Free calculator · No account required · Instant estimate