Building permit guides
Find out when a project needs a permit, what inspectors look for, and how to get through the process without surprises.
Each guide starts from the International Residential Code, the model code most US jurisdictions adopt for houses, and explains where local rules commonly differ. Your local building department decides what applies to your address.
Do I need a permit for…
Do I Need a Permit for a Deck?
Usually, yes. The model International Residential Code exempts only small decks: 200 square feet or less, no more than 30 inches above grade at any point, not attached to the house, and not serving a required exit door. Many cities tighten that exemption, so confirm with your local building department before you build.
Do I Need a Permit for a Fence?
It depends on height, location, and your city. The model International Residential Code exempts fences up to 7 feet tall from a building permit, but many cities require a fence or zoning permit at any height, and fences that serve as pool barriers almost always need one.
Do I Need a Permit for a Shed?
Often not for a small storage shed. The model International Residential Code exempts one-story detached accessory structures up to 200 square feet, but some jurisdictions use a lower limit such as 120 square feet, and adding electricity, plumbing, or living space usually requires permits. Zoning setbacks apply either way.
Do I Need a Permit to Replace a Roof?
In most US jurisdictions, yes. A full roof replacement or reroof usually requires a building permit, while small repairs often do not. Where the line falls between a repair and a replacement is set locally, so check with your building department before work starts.
Do I Need a Permit to Replace a Water Heater?
In most US jurisdictions, yes. Replacing a tank or tankless water heater usually needs a plumbing permit (and often a gas or electrical permit), even for a same-size swap, because the venting, gas connection, and relief valve are safety items. A few places exempt like-for-like replacements, so confirm with your local building department.
Do I Need a Permit to Replace HVAC?
Usually, yes. Replacing a furnace, central air conditioner, heat pump, or ductless mini-split typically requires a mechanical permit, and often an electrical permit too. Portable units and minor repairs with like parts are generally exempt, but local rules vary, so confirm with your building department.
Do I Need a Permit for Electrical Work?
Most electrical work beyond minor repairs needs a permit, including new circuits, new outlets or fixtures, panel and service upgrades, EV chargers, and generators. The model International Residential Code (Section R105.2) exempts only a short list: replacing lamps, plugging approved equipment into existing receptacles, reinstalling receptacles (not new outlets), replacing breakers with the same capacity in the same location, and wiring under 25 volts and 50 watts. States and cities change that list a lot, so check with your local building department.
Do I Need a Permit to Replace Windows?
It depends on your jurisdiction and the scope. Many building departments require a permit for any window replacement, while others exempt same-size replacements that don't change the opening. Enlarging, adding, or moving a window almost always needs a permit because it changes the wall framing.
Do I Need a Permit for Solar Panels?
Yes. Grid-tied rooftop and ground-mounted solar systems almost always need a permit, usually covering both the structural mounting and the electrical work, and your utility separately has to approve the interconnection before you turn the system on. Small plug-in or off-grid devices that don't connect to house wiring are often exempt.
Do I Need a Permit for a Kitchen Remodel?
Cosmetic work like new cabinets, countertops, flooring, and paint usually does not need a permit under the model code. Once you add or move electrical circuits, plumbing, gas lines, or ventilation, or remove or alter walls, you almost always need one, and your city may set the line differently.
Do I Need a Permit for a Bathroom Remodel?
Replacing tile, a vanity, or a toilet in the same spot usually does not need a permit under the model code. Moving or adding plumbing, adding circuits or an exhaust fan, building a new shower, or changing walls usually does, and many cities require permits for more than the model code does.
Do I Need a Permit to Finish a Basement?
In most US jurisdictions, yes. Turning unfinished basement space into living space usually means framing, wiring, insulation and often plumbing or ductwork, and none of that is on the IRC's permit exemption list (R105.2). Painting, carpeting, tiling and similar finish work are exempt, and some cities also exempt like-for-like fixture swaps.
Do I Need a Permit for a Swimming Pool?
Almost always for an in-ground pool, and usually for an above-ground pool deeper than 24 inches. The model International Residential Code exempts only prefabricated pools less than 24 inches deep, and pools typically need separate electrical, plumbing, and barrier approvals as well.
Do I Need a Permit for an ADU?
Yes. Building an accessory dwelling unit (ADU), whether detached, attached, or converted from a garage or basement, requires a building permit and usually zoning approval, plus electrical, plumbing, and mechanical permits. Whether ADUs are allowed on your lot, and under what size, setback, and parking rules, depends on your city and state.
Do I Need a Permit for a Garage or Carport?
Almost always, yes. The model International Residential Code exempts only one-story detached accessory structures of 200 square feet or less (IRC R105.2 item 1), and a one-car garage is already larger than that. Attached garages and carports always need a permit under the model code, and many cities require one for every garage or carport regardless of size.
Do I Need a Permit for a Driveway?
Often not a building permit, but frequently another permit. The model International Residential Code exempts sidewalks and driveways from building permits (IRC R105.2 item 5). A new or widened curb cut, or any work on the apron between the street and your property line, usually needs a right-of-way permit from the city or county roads agency, and larger paving jobs can trigger grading, stormwater or zoning review.
Do I Need a Permit for a Retaining Wall?
Under the model International Residential Code, a retaining wall needs a permit if it is over 4 feet tall measured from the bottom of the footing to the top of the wall, or if it supports a surcharge such as a driveway, slope or building (IRC R105.2 item 3). Because the buried footing counts, a wall showing about 3 feet above ground can already be over the limit. Many cities set a lower threshold.
Do I Need a Permit for a Pergola or Patio Cover?
Often yes, especially for a solid-roof patio cover or anything attached to the house. The model International Residential Code has no exemption for pergolas or patio covers. Its R105.2 list exempts only wall-mounted window awnings projecting 54 inches or less (item 9), and arguably small one-story detached accessory structures of 200 square feet or less (item 1). Some cities exempt small patio covers; others, like Denver, permit every one.
Do I Need a Permit to Replace Siding?
Often, yes. The model International Residential Code exempts painting and similar finish work (IRC R105.2, Building item 6) but has no exemption for replacing siding, so full re-siding is permit work unless your state or city adds one. Some do: Virginia exempts unlimited siding replacement on houses outside high-wind areas, and Austin exempts up to 128 square feet.
Do I Need a Permit for Plumbing Work?
For anything beyond repairs, usually yes. The model International Residential Code (R105.2) exempts only stopping leaks, clearing stoppages and removing and resetting a toilet, as long as no pipes, valves or fixtures are replaced or rearranged. New or relocated lines, sewer and water service work need a permit nearly everywhere. Some states and cities also exempt like-for-like fixture swaps.
Do I Need a Permit for a Gas Line?
Yes, almost always. The model International Residential Code exempts only portable gas appliances and minor replacement parts (R105.2, Gas items 1-3). Any new or extended gas piping needs a permit and has to pass a pressure test of at least 1.5 times working pressure, never less than 3 psig, held for at least 10 minutes (IRC G2417.4).
Do I Need a Permit for a Generator?
For a permanently installed standby generator, yes. Expect an electrical permit for the generator and transfer switch, a gas permit for the fuel line, and often zoning or site-plan review for its location. A portable generator plugged into its own cords usually needs no permit, but connecting one to your home's wiring through a transfer switch or interlock does.
Do I Need a Permit for an EV Charger?
Plugging a Level 1 charger into an outlet you already have usually needs no permit. A Level 2 charger on a new 240-volt circuit, or any hardwired charger, needs an electrical permit almost everywhere. The work falls under Article 625 of the National Electrical Code, which calls for an individual branch circuit sized at 125 percent of the charger's rating. Some cities, Seattle among them, require a permit for every charger installation.
Do I Need a Permit for an Egress Window?
Yes, in practically every jurisdiction. Cutting a new egress opening in a foundation wall is structural work, and nothing in the IRC's permit exemption list (R105.2) covers it. Under the 2021 IRC the finished opening needs at least 5.7 square feet of net clear area (5.0 for grade-floor openings), 24 inches of clear height, 20 inches of clear width, and a sill no more than 44 inches above the floor, plus a 9-square-foot well if it sits below grade.
Do I Need a Permit for a Home Addition?
Yes. The model International Residential Code requires a permit to construct or enlarge a building (IRC R105.1), and the small-structure exemption in R105.2 covers only one-story detached accessory structures of 200 square feet or less, never an addition to the house. Expect zoning review, structural and energy code review, separate trade permits, and smoke and carbon monoxide alarm upgrades.
Do I Need a Permit for Foundation Repair?
Structural foundation repair almost always needs a building permit. Piering, underpinning, wall anchors and bracing change how the house is supported, and the model IRC's ordinary-repair exemption (R105.2.2) excludes cutting load-bearing supports. Many cities also require a licensed engineer's design and a final engineer's letter. Cosmetic crack sealing and some waterproofing may be exempt, depending on local rules.
Do I Need a Permit to Demolish a House?
Yes. The model International Residential Code requires a permit to demolish a building (IRC R105.1), and no exemption covers tearing down a house. Expect to show proof that gas, electric and water are shut off and the sewer line is capped before the permit is issued, and to clear any asbestos survey and historic or demolition-delay review your state or city requires. Detached sheds and other small accessory buildings are the main thing some cities let you remove without a separate demolition permit.
Understanding the permit process
City or County: Who Issues Your Building Permit?
Your mailing address doesn't decide who issues your permit. Learn how city limits, counties, townships and regional departments split permit authority.
How to Apply for a Building Permit
The building permit process explained: confirming you need one, finding the right office, documents to prepare, plan review, fees, and what happens after issuance.
How Much Does a Building Permit Cost?
How building permit fees are calculated, with real fee schedules from Denver, Phoenix, Seattle, and San Diego, state surcharges, and a checklist to estimate yours.
How Long Does a Building Permit Take?
Why permit timelines range from same-day to months, real review-time data from Seattle, San Diego, and Denver, state deadline laws, and how to avoid delays.
Building Inspection Stages Explained
What happens at each building inspection, from footings and rough-ins to framing, insulation, and final, plus how to schedule and pass inspections the first time.
What Is a Certificate of Occupancy?
What a certificate of occupancy is, when the building code requires one, temporary COs, how to get one after final inspection, and how to find one for an older home.
What Happens If You Do Work Without a Permit?
What happens when work is done without a permit: stop-work orders, added fees, fines, sale disclosure, and how to legalize unpermitted work with an after-the-fact permit.
Owner-Builder Permits Explained
How owner-builder permits work: state rules in CA, FL, AZ and TX, sale and rental limits, trade restrictions, city examples, and the liability you take on.
When Does a Building Permit Expire?
How the IRC 180-day rule works, how cities like Phoenix, Seattle, San Diego and NYC set permit lifetimes, and what it costs to extend or reactivate a permit.
How to Look Up Building Permits for a Property
How to search a city's permit records by address, request older files and plans, read permit statuses, and spot red flags before you buy a house.
What Does a Permit Expediter Do, and Do You Need One?
What a permit expediter does, when hiring one is worth it, and the cities that license or register expediters, including New York City, Philadelphia and San Francisco.
Questions to ask about zoning and plan review
A building permit is often not the only approval a project needs. Before committing to a design, use the property address and proposed work to ask the local planning and building offices which reviews apply, and keep their answers with your project records.
- Which office can confirm the zoning designation and permitted use for this property?
- Do the proposed size, location, height, or use raise setback, lot coverage, access, or parking questions?
- Is the property in a historic district, floodplain, shoreline, or other overlay with its own review?
- Are there separate approvals, such as a variance or design review, to resolve before submitting the building application?
- What plans and supporting documents should be submitted, and how should revisions be identified?
- Where will review comments appear, and who should respond to them?