Radon code adoption map

Every US state, DC, and Canadian province, with its radon-resistant new construction (RRNC) code adoption status, the standard adopted, and a source citation. The IRC radon appendix (Appendix F, then AF, now BE) is not adopted by default anywhere — each row below is the jurisdiction's own adoption, cited.

Primary US source: AARST RRNC Code Adoption Data by State and Locality. Prepared 2026-08-26. See each row for its specific citation, including corrections verified against primary statute text.

United States (51)

Jurisdiction	Adopted standard	Status	Effective	Source
Alabama	Local-only: Decatur (2009 App. F), Muscle Shoals (2003 code, adopted 2005), Mobile (2021 IRC incl. Appendix AF)	Local / partial	—	Source
Alaska	None	None found	—	Source
Arizona	Local-only: Flagstaff (2018 IRC App. F), Tolleson (2012 IRC App. F), Coconino County (2012 IRC App. F)	Local / partial	—	Source
Arkansas	None	None found	—	Source
California	Local-only: South Lake Tahoe (2015), Lakewood/LA County (2021 IRC App. F), Plymouth/Amador County (2018 IRC App. F)	Local / partial	—	Source
Colorado	Local-only patchwork, no statewide building code: 43 cities + 19 counties as of AARST's 9/20/2021 count (e.g., Denver, Boulder, Aspen, Fort Collins, Vail — mostly Appendix F; Northglenn on 2021 IRC Appendix AF)	Local / partial	—	Source
Connecticut	Statewide: 2022 CT State Building Code, Appendix AF ("Passive Radon Gas Controls," 2021 IRC portion) — required for all new detached 1- and 2-family dwellings and townhouses. Originally adopted as Appendix F in the 2016 CT code.	Mandatory	2016 (original adoption; current text carried into 2022 code cycle)	Source
Delaware	None	None found	—	Source
District of Columbia	Statewide: 2017 DC Construction Codes include IRC Appendix F	Mandatory	2017	Source
Florida	Local-only: Charlotte County (Florida Standard for Passive Radon Resistant New Residential Building Construction), City of Jacksonville, City of Pensacola, City of Sanibel	Local / partial	—	Source
Georgia	Local-only: Gwinnett County (2014 App. F), DeKalb County (2015 IRC incl. App. F), City of Loganville (App. F, adopted 7/14/2022)	Local / partial	—	Source
Hawaii	None	None found	—	Source
Idaho	Local-only: ~10 jurisdictions, mostly 2018 IRC Appendix F — Ketchum, Sun Valley/Blaine County, Teton County, Coeur d'Alene, Hailey, Driggs, Carey, Rexburg	Local / partial	—	Source
Illinois	Statewide: Radon Resistant Construction Act (420 ILCS 52); IEMA rule at 32 Ill. Adm. Code 422.160 ("Mitigation Standard for New Residential Construction"), applies to all 1- and 2-family dwellings statewide regardless of local code adoption	Mandatory	1998-06-01 (rule effective date per Illinois Register)	Source
Indiana	None	None found	—	Source
Iowa	Statewide: Iowa Code §103A.8E (enacted via HF 2297) requires the state building code to mandate a passive radon mitigation system per 2021 IRC Appendix AF for all new 1- and 2-family residential construction commenced after the requirement is formally adopted by the building code commissioner. Local (pre-existing, various editions/appendices): Johnson County (2018 IRC App. F), Muscatine County (2006 IRC App. F), Shelby County (2018 IRC w/ App. F), Coralville (2024 IRC App. BE), Iowa City (2024 IRC App. BE), North Liberty (2021 IRC App. AF), Harlan (2018 IRC App. F)	Mandatory	2026-07-01 (statute effective date; actual construction requirement contingent on commissioner rulemaking per news reporting — "in flux" as of the law's passage)	Source
Kansas	Local-only: 13 cities/counties, various IRC editions w/ Appendix F — Manhattan, Topeka, Lawrence, Lenexa, Salina, Junction City, DeSoto, Eudora (App. AF), Gardner, Olathe, Edgerton, Shawnee County, Douglas County	Local / partial	—	Source
Kentucky	Local-only: 30 counties (Adair, Allen, Barren, Bourbon, Boyle, Bullitt, Casey, Clark, Cumberland, Fayette, Franklin, Green, Harrison, Hart, Jefferson, Jessamine, Lincoln, Marion, Mercer, Metcalfe, Monroe, Nelson, Pendleton, Pulaski, Robertson, Russell, Scott, Taylor, Warren, Woodford) — Kentucky Housing Corporation mandates 2018 IRC Appendix F in these counties	Local / partial	—	Source
Louisiana	None	None found	—	Source
Maine	Statewide: Maine Uniform Building and Energy Code (MUBEC) incorporates the Maine model radon standard (ASTM E1465-06/2008) for new residential construction; replaced the prior Title 25 §2466 local-opt-in framework	Mandatory	2010-12-01 (MUBEC effective date; mandatory municipal enforcement phased in 2010–2012)	Source
Maryland	Statewide, Zone 1 counties: Baltimore County (2021 IRC App. AF), Calvert County (2018 IRC App. F), Carroll County (via state building code framework), Frederick County (2021 IRC App. F), Howard County (2015 IRC App. F), Montgomery County (2021 IRC App. AF), Washington County (2021 IRC App. AF)	Mandatory	—	Source
Massachusetts	Statewide, Zone 1: Worcester, Essex, and Middlesex Counties required to implement 2015 IRC Appendix F	Mandatory	—	Source
Michigan	Statewide, Zone 1: Michigan Residential Code requires 2015 IRC Appendix F in Branch, Calhoun, Cass, Hillsdale, Jackson, Kalamazoo, Lenawee, St. Joseph, Washtenaw counties	Mandatory	—	Source
Minnesota	Statewide: Minnesota Rules 1303.2400–1303.2403 (Radon Control Systems), Dept. of Labor and Industry — mandatory passive radon control system in all new residential structures statewide	Mandatory	—	Source
Mississippi	None	None found	—	Source
Missouri	Local-only: 51 counties/cities on 2018 IRC Appendix F (e.g., Platte County, St. Louis City, Kansas City, Springfield, Columbia, Independence, Joplin)	Local / partial	—	Source
Montana	None	None found	—	Source
Nebraska	Local-only: Hastings, McCook, Norfolk, Pender, Madison, Stanton, Wayne, Columbus — 2018 IRC Appendix F	Local / partial	—	Source
Nevada	None	None found	—	Source
New Hampshire	None	None found	—	Source
New Jersey	Statewide, Zone 1 ("Tier 1"): New Jersey's own Radon Hazard Subcode (not IRC-Appendix based) required in Tier 1 municipalities across Burlington, Camden, Cumberland, Gloucester, Hunterdon, Mercer, Middlesex, Monmouth, Morris, Passaic, Salem, Somerset, Sussex (all), and Warren (all) counties	Mandatory	—	Source
New Mexico	Local-only: Santa Fe (2021 IRC App. F), Alamogordo (2024 IRC App. BE)	Local / partial	—	Source
New York	Local-only: Georgetown/Madison County (2018 IRC App. F), Lima & Caledonia/Livingston County (2000 IRC App. F)	Local / partial	—	Source
North Carolina	None	None found	—	Source
North Dakota	Local-only: City of Fargo — 2024 IRC Appendix BE	Local / partial	—	Source
Ohio	Local-only: Union County (2024 IRC App. BE), Powell City (2009 IRC App. F)	Local / partial	—	Source
Oklahoma	None	None found	—	Source
Oregon	Statewide, Zone 1 (county-level): 2018 IRC Appendix AF adopted in Baker, Clackamas, Hood River, Multnomah, Polk, Washington, Yamhill counties	Mandatory	—	Source
Pennsylvania	Local-only: ~15 townships across Chester, Delaware, Montgomery, Adams, Berks, Lancaster, York, Washington counties, mostly 2003–2018 IRC Appendix F, some 2021 Appendix AF (Lower Merion Twp.)	Local / partial	—	Source
Rhode Island	None	None found	—	Source
South Carolina	Local-only: Greenville County — 2021 IRC Appendix AF	Local / partial	—	Source
South Dakota	None	None found	—	Source
Tennessee	Local-only: Townsend (2018 IRC App. F), Dandridge (2012 IRC App. F)	Local / partial	—	Source
Texas	None	None found	—	Source
Utah	None	None found	—	Source
Vermont	None	None found	—	Source
Virginia	Local-only: 10 counties (Amelia, Buckingham, Louisa, Montgomery, Nottoway, Orange, Rockbridge, Shenandoah, Tazewell, Wythe) + 7 cities (Blacksburg, Buena Vista, Christiansburg, Lexington, Radford, Roanoke, Salem) — 2021 IRC Appendix F	Local / partial	—	Source
Washington	Statewide, Zone 1: Washington State Building Code (2021 IRC portion) requires a complete (not just rough-in) radon system in Zone 1, and elsewhere only where there is an unvented crawl space	Mandatory	—	Source
West Virginia	Local-only: Berkeley County (2018 IRC App. F), Monongalia County (2003 IRC App. F), Jefferson County (2018 IRC App. F)	Local / partial	—	Source
Wisconsin	None	None found	—	Source
Wyoming	Local-only: 17 towns (Alpine, Burns, Star Valley Ranch, Diamondville, Glenrock, Green River, Gurnesey, Jackson, Lusk, Meeteetse, Mills, Mt. View, Pine Haven, Rawlins, Riverton, Torrington, Worland) + Teton County — 2024 IRC Appendix BE	Local / partial	—	Source

Canada (10)

Jurisdiction	Adopted standard	Status	Effective	Source
British Columbia	BC Building Code 2024, Subsection 9.13.4	Mandatory	2024-03-08	Source
Alberta	Alberta Building Code 2014, Part 6	Mandatory	2015-11-01	Source
Saskatchewan	Follows National Building Code of Canada — radon rough-in with stub required under NBC 9.13.4. Currently on NBC 2020 edition (adopted by regulation under the Construction Codes Act); prior edition was NBC 2015	Mandatory	2024-01-01 (NBC 2020 edition currently in force; NBC 2015 was in force 2018-01-01 to 2023-12-31)	Source
Manitoba	Manitoba Building Code, M.R. 78/2023, adopts NBC 2020. Radon rough-in provision (pipe stub through slab into sub-slab gravel layer, sealed 6-mil poly air/vapour barrier) has been in Manitoba's legally binding code since the 2010 NBC model code was adopted	Mandatory	2011-04-01 (original radon rough-in provision, carried forward through subsequent code editions incl. current M.R. 78/2023)	Source
Ontario	Ontario Building Code 2024, Section 9.13.4	Mandatory	2025-01-01	Source
Quebec	Code de construction du Québec, Chapitre I – Bâtiment, section 9.13.4.6 (formerly A-9.13.2.1(3)) — RBQ regulation extending underground-gas (radon) protective measures province-wide	Mandatory	2022-01-08	Source
New Brunswick	Follows National Building Code of Canada — radon rough-in with stub required under NBC 9.13.4. NB currently has NBC 2020 (and National Energy Code 2020) adopted	Mandatory	Not precisely confirmed — secondary sources describe NB homes built after ~2015 as having rough-in already; exact date NB's radon rough-in requirement first took legal effect not found in a primary NB source this pass	Source
Nova Scotia	Follows National Building Code of Canada — radon rough-in required under NBC 9.13.4. NS Building Code Regulations are transitioning to NBC 2020 (Tier 1 effective 2024-01-01, full implementation 2025-04-01); radon rough-in provision predates this transition via the prior NBC-2015-based code	Mandatory	2025-04-01 (current NBC 2020 full-implementation date; underlying radon rough-in requirement predates this)	Source
Prince Edward Island	Buildings Codes Act (2017) adopted the 2015 National Building Code, including radon rough-in provisions (NBC 9.13.4). PEI historically had no province-wide building code; the Act applies only where a municipality has adopted and enforces it	Local / partial	2017 (Act passed; Charlottetown, Stratford, Summerside already enforcing at that point; rollout to other municipalities ongoing/incomplete)	Source
Newfoundland and Labrador	NL Regulation 2/19 adopts the National Building Code of Canada, 2015 edition, province-wide except Part 9 as it relates to one- and two-family dwellings within Group C — i.e., the radon rough-in requirement (which lives in NBC Part 9, section 9.13.4) is explicitly carved out of the provincial mandate for the single/two-family homes that are radonplans' target building type. Enforcement for that building type falls to individual municipalities under the Building Standards Act	Local / partial	2019 (regulation)	Source

Jurisdiction detail pages

The table above is the adoption status. For the code citation, effective date, and what it means for a project in the jurisdictions we cover in depth, see the radon codes by jurisdiction reference, or the standards themselves: 2024 IRC Appendix BE and ANSI/AARST CCAH-2020.