Residential Building Code Edition by State: IRC, NEC, and Energy Code
One- and two-family homes. Each row is the statewide baseline from a state source. Cities and counties can enforce a different edition or add amendments, so always confirm the edition and amendments for your address with your local building department.
There is no single national residential building code. The International Code Council publishes the IRC every three years, the National Fire Protection Association publishes the NEC, and each state decides which edition, if any, to adopt, and what to change. The result is a patchwork: some states enforce a 2024 edition, some are still on 2015, and some have no statewide residential building code at all.
This page lists the state-level baseline for the three codes that matter most on a remodel: the residential building code, the electrical code, and the energy code. Every value comes from a state agency page, an adopted rule, or a statute, with the effective date in parentheses. Where we could not find a state source, the cell says so and we have not filled it in from a secondary tracker. Several of the common online tables are wrong or out of date for the states below.
Some states move in the next few months. Florida's 9th Edition and Washington's 2026 NEC take effect December 31, 2026, South Carolina and Louisiana have 2024-edition cycles scheduled for January 1, 2027, and Michigan, North Carolina, and Connecticut each have an adopted update that is blocked or has no start date. Check the date on this page, and then ask your building department.
A basement finish is a permitted alteration, so the edition your state or city enforces decides egress, insulation, alarms, and electrical requirements. Free, no signup.
How to Read This Table
An edition in parentheses with a date is the effective date of that edition in that state. "Adopted" and "effective" are not the same: a state can adopt a code that takes effect months later, or one that a court or a certification step has not yet released. "Local" means the state has no statewide code of that type and cities and counties decide. "Not verified: check locally" means we did not find a state source for that cell, and you should ask your building department rather than assume. The adoption level column says whether the baseline is mandatory statewide, mandatory with local amendments, a minimum, or a local option.
Northeast and Mid-Atlantic
Most Northeastern states adopt the IRC statewide with their own amendments. Three of them (Massachusetts, New York, and Pennsylvania) moved to a new edition in the last year, and several have a 2024-edition update scheduled or stalled. New York City runs its own codes, and Connecticut's 2024-based update has not been approved.
| State | Residential code | Electrical (NEC) | Energy code | Adoption level and notes |
|---|---|---|---|---|
| Connecticut | 2021 IRC-based CT State Building Code (in effect since 10/1/2022) | Not verified: check locally | 2021 IECC (since 10/1/2022) | Statewide. A 2024-based code was expected 7/1/2026 but has not been approved; no effective date |
| Delaware | Not verified: check locally | 2023 NEC (1/1/2026) | 2024 IECC with zero-net-energy-capable amendments (4/11/2026) | Energy code is statewide; residential building code adoption not verified |
| District of Columbia | 2017 DC Residential Code (2015 IRC base) (5/29/2020) | 2014 NEC (5/29/2020) | 2015 IECC / ASHRAE 90.1-2013 (5/29/2020) | District-wide mandatory (Title 12 DCMR) |
| Maine | 2021 IRC via MUBEC (4/7/2025) | 2026 NEC with ME amendments (7/1/2026) | 2021 IECC via MUBEC (4/7/2025) | Statewide; enforcement is mandatory only in municipalities of 4,000 or more people |
| Maryland | 2021 IRC (COMAR 09.12.51, 5/29/2023) | No single adopted edition; the state electricians board must enforce the most recent NEC within 18 months of publication | 2021 IECC (5/29/2023) | Statewide with local amendments; locals may not weaken the IECC or sprinkler and wind provisions |
| Massachusetts | 780 CMR 10th Ed. (2021 IRC with MA amendments) (10/11/2024) | 2026 NEC, 527 CMR 12.00 (permits after 4/24/2026) | 10th Ed. base energy code (2021 IECC with MA amendments); stretch codes are opt-in by town | Statewide mandatory; stretch and specialized codes adopted locally |
| New Hampshire | 2024 IRC (7/1/2026); old or new edition may be used through 12/31/2026 | 2023 NEC (7/1/2025) | 2018 IECC | Statewide mandatory (RSA 155-A); local amendments limited to administrative matters from 7/1/2026 |
| New Jersey | 2021 IRC (N.J.A.C. 5:23-3.21) | Not verified: check locally | Not verified: check locally | Statewide Uniform Construction Code; DCA anticipates a 2024 IRC adoption but no notice was found |
| New York | 2025 Residential Code of NYS (2024 IRC base) (12/31/2025) | Not verified: check locally | 2025 Energy Conservation Construction Code of NYS (12/31/2025) | Statewide except New York City, which runs its own codes |
| Pennsylvania | 2021 IRC with PA modifications, 34 Pa. Code 403.21 (1/1/2026) | 2020 NEC for one- and two-family homes (stated in one state notice only) | 2021 IRC Chapter 11 / IECC 2021 with PA amendments (1/1/2026) | Statewide mandatory; municipalities may opt out of local enforcement and third-party agencies do residential inspections |
| Rhode Island | 2021 IRC, SBC-2 (12/1/2025) | 2023 NEC, SBC-5 (12/1/2025) | 2024 IECC (12/1/2025) | Statewide mandatory (R.I. Gen. Laws 23-27.3) |
| Vermont | No residential building code among those adopted by the Division of Fire Safety | 2023 NEC via 2025 Vermont Electrical Safety Rules (11/5/2025) | RBES 2024 (7/1/2024); revised rules effective 7/14/2026 allow the 2020 or 2024 edition | Residential energy standards are statewide (30 V.S.A. 51); building code is not statewide |
South
Southern states mix statewide mandatory codes (Virginia, South Carolina, Louisiana, Georgia) with local-option adoption (West Virginia, Mississippi). North Carolina and Oklahoma are mid-transition, and South Carolina and Louisiana each have 2024-edition cycles scheduled for January 1, 2027.
| State | Residential code | Electrical (NEC) | Energy code | Adoption level and notes |
|---|---|---|---|---|
| Alabama | 2015 IRC with AL amendments (enforcement began 10/1/2016) | No statewide residential adoption found; the 2020 NEC (7/1/2022) applies to buildings under the state construction management division | 2015 IECC with AL amendments (10/1/2016) | Residential codes are adopted by the Alabama Energy and Residential Codes Board; which jurisdictions must enforce them is not confirmed |
| Arkansas | 2021 Arkansas Fire Prevention Code, Vol. III, Residential (2021 IRC) (1/1/2023) | 2026 NEC (17 CAR 210-401); the rule text states no effective date, and companion sections show 9/3/2026 | 2014 Arkansas Energy Code (2009 IECC with state amendments) (1/1/2015) | Statewide rule; the State Fire Marshal encourages local adoption by ordinance |
| Florida | FBC-Residential 8th Ed. (2021 I-Codes base) (12/31/2023); 9th Ed. (2024 I-Codes base) scheduled 12/31/2026 | Not verified: check locally | FBC-Energy Conservation 8th Ed. (12/31/2023) | Statewide Florida Building Code with limited local amendments |
| Georgia | 2024 IRC with GA amendments (1/1/2026) | 2023 NEC (1/1/2025) with 2026 GA amendments (1/1/2026) | 2015 IECC with GA supplements and amendments | Statewide mandatory minimum standard codes; DCA has posted further amendments for 1/1/2027 |
| Kentucky | 2018 Kentucky Residential Code, 3rd Ed. (2015 IRC base) (12/3/2024) | 2023 NEC (1/1/2025); some residential articles deferred to 7/15/2026 | 2009 IECC | Statewide uniform code; locals may not adopt another residential code |
| Louisiana | 2021 IRC with LA amendments (1/1/2023) | 2020 NEC (1/1/2023) | 2021 IECC with LA amendments (7/1/2023) | Statewide mandatory State Uniform Construction Code. A 2024 I-Codes and 2023 NEC update is proposed for 1/1/2027 and is not final |
| Mississippi | No binding statewide residential code | Local | Local | Counties and municipalities adopt state-listed codes unless they opted out (SB 2378, 2014) |
| North Carolina | 2018 NC Residential Code is in force. The 2024 code (2021 IRC base) is adopted but has no effective date | The 2020 NC Electrical Code (11/1/2021) excludes one- and two-family dwellings; see its amendments | Not verified: check locally | Statewide with local enforcement. The 2024 code takes effect 12 months after the State Fire Marshal certifies conditions in S.L. 2025-2 |
| Oklahoma | 2024 IRC (OAC 748:20-6-1), scheduled effective 9/14/2026; confirm final publication | Not verified: check locally | Not verified: check locally | State minimum (Oklahoma Uniform Building Code Commission); locals may be more restrictive |
| South Carolina | 2021 SC Residential Code (2021 IRC) (1/1/2023) | 2020 NEC (1/1/2023) | 2009 IECC, set by statute (Act 143 of 2012) | Statewide mandatory. The 2024 IRC and 2023 NEC were adopted 8/26/2025 and take effect 1/1/2027 |
| Tennessee | 2018 IRC with TN amendments (7/16/2020) | 2017 NEC (3/19/2018) | 2018 IECC, residential (7/16/2020) | State minimum; locals may not adopt less stringent standards, and opt-out provisions exist |
| Texas | IRC as it existed on 5/1/2012 is the municipal residential baseline; cities may adopt later editions | 2026 NEC (9/1/2026) | 2015 IRC Chapter 11 (9/1/2016) | Locally enforced; no statewide building code for most homes. NEC is statewide through TDLR |
| Virginia | 2021 Virginia Residential Code (1/18/2024) | NFPA 70-2020 (1/18/2024) | 2021 IECC (1/18/2024) | Statewide mandatory USBC with local enforcement (Va. Code 36-98). A 2024 USBC cycle is tentatively October 2027 |
| West Virginia | 2018 IRC with WV amendments (8/1/2022) | 2020 NEC (8/1/2022) | 2015 IECC, residential, with a 5 ACH50 amendment (8/1/2022) | Local option: the State Building Code applies where a locality adopts it. The rule sunsets 8/1/2027 |
Midwest
The Midwest has the most local-only states and the most surprises. Iowa moved all the way to the 2024 IRC, Michigan is blocked from its 2021 update by a court order, Indiana's statewide electrical rule is still the 2009 code, and Wisconsin and Illinois set their own state codes rather than adopt the IRC outright.
| State | Residential code | Electrical (NEC) | Energy code | Adoption level and notes |
|---|---|---|---|---|
| Illinois | No statewide residential building code; adopted locally | Local | 2024 Illinois Energy Conservation Code (2024 IECC with IL amendments) (11/30/2025) | Building codes are local; the energy code is mandatory statewide for residential |
| Indiana | 2020 Indiana Residential Code (2018 IRC first printing with IN amendments), 675 IAC 14-4.4 (12/26/2019) | Indiana Electrical Code, 2009 Edition, which is NFPA 70-2008 (675 IAC 17-1.8). A 2023 NEC rule has been proposed | Not verified: check locally | Statewide under the Fire Prevention and Building Safety Commission |
| Iowa | 2024 IRC with Iowa amendments (9/10/2025), with a 12-month transition | 2023 NEC with Iowa amendments (7/1/2025) | 2012 IECC residential provisions with Iowa amendments (reaffirmed 9/10/2025) | State code binds state-regulated buildings and jurisdictions that adopt it; the residential energy code applies statewide |
| Kansas | No statewide residential code found; local adoption | 2008 NEC, K.A.R. 22-1-3 (State Fire Marshal; amended 2/4/2011) | No statewide residential energy code found | Local for residential; only the Kansas Fire Prevention Code is statewide |
| Michigan | 2015 Michigan Residential Code is in force. The 2021 code was stayed by a 7/7/2025 court order and has no effective date | Not verified: check locally | 2015 IECC, residential provisions (the 2021 update is also stayed) | Statewide under the Stille-DeRossett-Hale Single State Construction Code Act |
| Minnesota | 2020 Minnesota Residential Code (2018 IRC base), Minn. R. ch. 1309 (3/31/2020) | 2026 NEC (8/17/2026) | Not verified: check locally | Statewide mandatory. A 2024 IRC rulemaking is open with no date |
| Missouri | No statewide residential code found; counties may adopt (enabling statute RSMo 64.170) | Not verified: check locally | Not verified: check locally | Local; Kansas City, for example, enforces its own 2018 code package |
| Nebraska | 2018 IRC (Neb. Rev. Stat. 71-6403) | 2023 NEC with amendments (8/1/2024) | 2018 IECC (7/1/2020) | Building code is a local option; the energy code is statewide |
| North Dakota | Not verified: check locally | 2026 NEC (7/1/2026), NDAC 24.1-02-01 | Not verified: check locally | Statewide electrical standards; residential building and energy adoption not verified |
| Ohio | 2019 Residential Code of Ohio (2018 IRC base) (7/1/2019) | 2023 NEC through RCO Chapter 34 (3/1/2024) | RCO Chapter 11 (2018-based package; edition not read directly) | Statewide; the Board of Building Standards certifies local departments to enforce |
| South Dakota | No statewide residential code; municipalities may adopt the IRC up to the 2021 edition (SDCL 11-10-12) | 2023 NEC with SD exceptions (11/12/2024) | No statewide energy code found | Local for residential; statewide electrical inspection. A 2026 law raises the local-adoption ceiling to the 2024 IRC |
| Wisconsin | Uniform Dwelling Code, SPS 320 to 325, a state code rather than the IRC | 2023 NEC (9/1/2026), replacing the 2017 NEC | SPS 322 (state residential energy provisions, based on the 2009 IECC per DSPS materials) | Statewide for one- and two-family dwellings |
West, Mountain, and Pacific
The West is the most varied region. California, Oregon, and Washington have their own code families, Colorado and Arizona leave building codes to local governments, and Hawaii delegates to its counties. Several states here change editions in the next six months.
| State | Residential code | Electrical (NEC) | Energy code | Adoption level and notes |
|---|---|---|---|---|
| Alaska | Not verified: check locally | Not verified: check locally | Not verified: check locally | Not verified against a state source |
| Arizona | No statewide residential code found; adopted by cities and counties | Not verified: check locally | Not verified: check locally | Local; Phoenix, for example, enforces the 2024 I-Codes |
| California | 2025 California Residential Code (2024 IRC base) (1/1/2026) | 2025 California Electrical Code (2023 NEC base) (1/1/2026) | 2025 California Energy Code, Title 24 Part 6 (1/1/2026) | Statewide mandatory; applies to permit applications filed on or after 1/1/2026 |
| Colorado | No statewide building code; adopted locally | 2026 NEC (State Electrical Board rule 1.5; reported effective 8/1/2026, which is not stated in the rule text) | State minimum triggered when a jurisdiction updates any building code; the Model Low Energy and Carbon Code (2024 IECC base) from 7/1/2026 | Building local; electrical statewide; energy minimum on local code update (HB22-1362) |
| Hawaii | 2018 IRC at the state level; counties adopt and amend | 2020 NEC adopted by the State Building Code Council 3/15/2022 (the council page labels the link 2018 NFPA 70) | 2018 IECC at the state level | State adopts, counties amend within two years (HRS 107-24, 107-28). A 9/23/2025 emergency proclamation suspends code updates |
| Idaho | Not verified: check locally | 2023 NEC (Idaho Code 54-1001) | Not verified: check locally | Statewide electrical; residential building and energy adoption not verified |
| Montana | 2024 ICC codes including the 2024 IRC (9/26/2026) | 2023 NEC (9/26/2026), replacing the 2020 NEC | 2024 IECC (9/26/2026) | Statewide (ARM Title 24, chapter 301) |
| Nevada | No statewide residential building code found; adopted locally | No statewide NEC found | 2024 IECC, statewide (8/18/2024) | Energy minimum is statewide (NRS 701.220); building and electrical are local |
| New Mexico | 2021 New Mexico Residential Building Code (2021 IRC), 14.7.3 NMAC (7/14/2023) | 2020 New Mexico Electrical Code (2020 NEC), 14.10.4 NMAC (3/28/2023) | 2021 New Mexico Residential Energy Conservation Code, 14.7.6 NMAC (1/30/2024) | Statewide minimum codes (Construction Industries Division) |
| Oregon | 2023 Oregon Residential Specialty Code (2021 IRC base) (10/1/2023; mandatory 4/1/2024) | 2026 Oregon Electrical Specialty Code (2026 NEC) (10/1/2026) | ORSC Chapter 11 plus OAR 918-460-0500 (10/1/2023) | Statewide mandatory, administered by the Building Codes Division |
| Utah | 2021 IRC with Utah amendments (Utah Code 15A-2-103) | 2023 NEC (7/1/2025) | 2024 IECC (7/1/2026) | Statewide mandatory State Construction Code |
| Washington | 2021 WA State Residential Code (2021 IRC with WA amendments) (3/15/2024) | 2023 NEC (4/1/2024); 2026 NEC adopted effective 12/31/2026 | 2021 WSEC-Residential, WAC 51-11R (3/15/2024) | Statewide minimum in all counties and cities. The 2024 building codes take effect 5/3/2027 |
| Wyoming | Not verified: check locally | 2026 NEC (7/1/2026), per the State Fire Marshal | Not verified: check locally | No statewide residential building code confirmed from a state source |
Cities That Run a Different Code Than Their State
A state row is a baseline, not a guarantee. Large cities frequently adopt a newer edition or their own code family, and some states leave building codes to cities entirely. These city examples come from each city's own code pages.
| City | What it enforces | State baseline |
|---|---|---|
| New York City | 2022 NYC Construction Codes (building code on the 2015 IBC; no IRC) for applications on or after 11/7/2022 | NYS 2025 Uniform Code (2024 IRC base) |
| Chicago | Chicago Construction Codes (2019 modernization) and a Chicago Electrical Code on the 2017 NEC | Illinois: local building codes; 2024 IECC energy code |
| Denver | 2025 Denver Building and Fire Code on the 2024 IRC, IBC, IPC and IMC (12/31/2025); energy stays on the 2021 IECC | Colorado: local; state energy minimum on update |
| Phoenix | 2024 Phoenix Building Construction Code on the 2024 IRC (8/1/2025) | Arizona: local only |
| Houston | 2021 Houston Construction Code on the 2021 IRC and 2021 IECC (1/1/2024) | Texas: 2012 IRC municipal baseline; 2026 NEC statewide |
| Austin | 2024 IRC, IECC, UMC, and UPC with local amendments (7/10/2025) | Texas: 2012 IRC municipal baseline |
| Kansas City, MO | 2018 IRC and 2017 NEC (6/28/2020); 2021 IECC (7/1/2023) | Missouri: no statewide residential code |
Which Edition Changes Matter on a Remodel
Editions matter less than the specific rules that moved between them. Two that regularly change a remodel scope: the 2024 IRC renumbered the smoke alarm and carbon monoxide alarm sections (R314 and R315 became R310 and R311) and kept the permitted-alteration trigger, and the 2024 IRC renumbered stairs from R311.7 to R318.7. Our guides on smoke and CO alarm requirements for remodels and on stair code by state cover the specifics. If your state is two editions behind a neighbor, the practical effect is usually in energy requirements (insulation levels, air leakage, window U-factors) and in electrical protection rules such as GFCI and AFCI coverage.
How to Find Your Local Edition
Call or email your building department with your address and the type of project. Ask which editions of the residential, electrical, energy, plumbing, and mechanical codes are in force today and on what date they took effect, whether a newer edition is adopted or pending and which one applies to your permit application date, what local amendments exist and where they are published, whether your address is inside the department's jurisdiction (this matters in unincorporated areas of Texas, Missouri, Arizona and Colorado), which work needs a permit, and whether separate electrical, plumbing, or mechanical permits are required. Write down the answer, the staff member's name, and the date.
Standards & Citations
| Standard | Code / Section | Requirement |
|---|---|---|
| International Residential Code | IRC 2018, 2021, 2024 editions | Model residential building code published by the International Code Council; effective only where a state or locality adopts it, with its own amendments. |
| National Electrical Code | NFPA 70 2020, 2023, 2026 editions | Model electrical code published by NFPA; adopted by states and localities on different schedules. |
| International Energy Conservation Code | IECC 2018, 2021, 2024 editions | Model energy code for residential buildings; many states adopt it or a state-specific equivalent. |
Apply These Requirements
Open a calculator to run this guide’s requirements against your own project.
Basement Remodel Calculator
A basement finish is a permitted alteration, so the edition your state or city enforces decides egress, insulation, alarms, and electrical requirements.
Joist Span Calculator
Span tables are tied to a specific IRC edition, so knowing which one applies to your project matters before you rely on a result.
Wire Size Calculator
Wire sizing and protection rules follow the NEC edition your jurisdiction enforces, which this page shows by state.
Insulation Calculator
Insulation levels are set by the IECC edition or state energy code you are under, which this page shows by state.
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Frequently Asked Questions
Which building code does my state use?
Most states adopt the International Residential Code, but the edition and amendments vary. Find your state in the table on this page for the statewide baseline and effective dates, then confirm with your local building department, because cities and counties can enforce a different edition. A few states, including Illinois, Missouri, Arizona and Colorado, leave residential building codes to local governments.
Which states use the 2024 IRC?
From the state sources we checked: Georgia (effective 1/1/2026), Iowa (9/10/2025), New Hampshire (7/1/2026), Montana (9/26/2026), and Oklahoma (scheduled 9/14/2026, confirm final publication). New York's 2025 code is based on the 2024 IRC, and California's 2025 code is too. Other states have updates scheduled or adopted but not yet effective.
Which states have adopted the 2026 NEC?
The states we verified on a state source: Maine (7/1/2026), Massachusetts (permits after 4/24/2026), Minnesota (8/17/2026), North Dakota (7/1/2026), Texas (9/1/2026), Oregon (10/1/2026), Wyoming (7/1/2026), Colorado (state rule adopted in 2026, with the 8/1/2026 date not stated in the rule text), and Washington (12/31/2026). Arkansas has adopted the 2026 NEC with an unstated effective date.
What if my state has no statewide residential code?
Your city or county sets the code, and it may differ from the neighboring jurisdiction. Illinois, Missouri, Arizona and Colorado are examples. Call the building department that covers your address and ask which editions and amendments they enforce.
Why does my permit say a different edition than this page?
This page shows the statewide baseline. Local jurisdictions can adopt a newer edition or add amendments, and some states key the edition to the permit application date or a transition window. For example, New Hampshire allows either the 2021 or 2024 IRC through 12/31/2026. Always go by what the permit office tells you for your address.
Why are some cells marked not verified?
We only show a value when we found it on a state agency page, an adopted rule, or a statute. For some states the only available data was a secondary tracker, which conflicted with state sources in many of the states we checked, so we left those cells open rather than guess. Plumbing and mechanical code editions are not covered on this page.
How often does this change?
Editions move every three years on the ICC cycle, but adoption lags by one to three years and is sometimes delayed by courts or certification steps. Several states change in the next six months, so check the date at the top of this page.
Related Code Guides
Smoke and CO Alarm Requirements for Remodels
When a permitted remodel triggers smoke and CO alarms under the 2024 IRC, the exceptions, placement rules, and states with special resale or battery rules.
Re-Roofing Code Requirements: Layers, Permits, and Wind
What the IRC says about tearing off vs. roofing over old shingles, ice barrier, fasteners, and permits, plus the states with special re-roof rules.
Frost Depth by State: How Deep Footings Must Go
How deep footings must go: the IRC 12-inch rule, frost depths from 11 state codes, county tables for MN, IN, OR and KY, and what is exempt.
Stair Code by State: Rise, Run, Headroom and Handrails
IRC stair rules and the seven states that change them: 7 3/4 in rise and 10 in run, and where an 8 1/4 in riser over a 9 in tread is legal instead.
Egress Window Requirements by State: What the Code Actually Changes
The IRC R310 escape-window rule, the existing-window replacement exemption, and the 7 states that loosen or tighten it for basements without a bedroom.
EV-Ready Wiring Requirements for New Homes by State
Which states require EV-capable or EV-ready wiring in new homes, the 2024 IRC's optional appendix, and why California's rule is weaker than Washington's.