Where to find the building codes for your state, free
The code that applies to your job is decided by your state and then, very often, changed by your city or county. There is no single national code, but there is a single family of them, and you can read all of them online without paying for the book.
How codes work in the US
The International Code Council publishes the model codes most of the country uses: the International Residential Code for one- and two-family homes, the International Building Code for everything else, plus plumbing, mechanical, fuel gas, energy and existing-building codes. Electrical work follows the National Electrical Code, published by the NFPA.
Each state adopts a version of these, often a few years behind the newest edition, and adds its own amendments. Then the city or county you are working in can amend it again. So the answer to "what code applies" is always: the state's adopted edition, as amended by the local building department that issues your permit.
A few states write their own. California's Title 24 and the Florida Building Code are based on the ICC codes but published separately with substantial changes.
Where to read them free
- ICC codes: codes.iccsafe.org has a free public-access version of every ICC code, including the editions your state adopted. Reading is free; printing and search need a paid account.
- The electrical code: nfpa.org offers free online access to the NEC with a free account. Same deal, read only.
- What your state adopted: iccsafe.org keeps an adoption map by state showing which edition of each code is in force. Your state's building or licensing board site says the same and lists the state amendments.
- Everything in one place by address: UpCodes (up.codes) lets you pick a state or city and browse the adopted codes with local amendments folded in. The browsing is free.
- Local amendments: your city or county building department, on its website under "building codes" or "adopted codes", and on the phone. This is the part no national site reliably has.
Before pricing anything that needs a permit, call the building department and ask which code edition and which amendments they inspect to. Ten minutes, and it is the answer your inspector will use.
The parts that catch contractors most often
- Deck ledger attachment, guard height and stair geometry, which changed between IRC editions.
- Egress window size in bedrooms, especially in basement finishes.
- GFCI and AFCI requirements, which have expanded with each NEC cycle.
- Energy code: insulation values and air sealing, where the state adopted a newer energy code than its building code.
- Smoke and carbon monoxide alarm placement when you touch a bedroom or a permit triggers an upgrade.
Put the code on the estimate
When a job has to meet a code that changes what you build, say so on the estimate. "Guard rail 36 inches per IRC as adopted by the county" tells the client why the rail is the height it is and tells the inspector you knew. It is also what stops a client asking for a shorter rail to save money.
Common questions
Do I need to buy the code book?
For reading and checking, no; the free online versions are the same text. Contractors who work to a code every day usually buy the book or a subscription for search and bookmarks, and licensing exams often allow the printed book.
Which edition should I follow if the state and the city differ?
The one the permitting authority inspects to, which is normally the state edition with local amendments. When in doubt the building department that issues the permit is the answer.
Does this cover Canada or Mexico?
No. Canada uses the National Building Code of Canada, adopted by province. Mexico's codes are set by state and municipality. This page is about the United States.