Radon laws and requirements by state

Yes. Iowa HHS certifies radon measurement specialists and credentials mitigation specialists and labs. Mitigation rules rewritten effective July 1, 2026 require the national ANSI/AARST installation standards and a post-mitigation level below 4 pCi/L; owners fixing their own building are exempt. Credentialed testers must report results to the state within 30 days. How to check one →

Disclosure required. The state disclosure statement includes a radon item: any known tests, date of the last report and the results. Buyers must also get the Iowa HHS radon fact sheet for home buyers and sellers. Testing itself is not required.

Testing required. Every public school attendance center must test by July 1, 2027 and post results on the district website. Our Iowa school radon tracker →

Testing required for licensed centers at ground level, using a basement, or over a basement: within a year of an initial or renewal license. Over 4.0 pCi/L means mitigation; retest every 2 years if mitigated, every 5 years if the first test was below 4.0.

No statewide rule found. Iowa City requires testing of single-family and duplex rentals, with mitigation within 90 days at 4.0 pCi/L or higher. Iowa City contractors →

Signed into law, not in effect yet. HF 2297 (signed May 19, 2026) requires passive radon-resistant construction in new one- and two-family homes once the state building code commissioner adopts a rule. The draft rule says radon testing is not required; its public hearing was Oct. 21, 2026. We found no adopted rule yet. Locally, Johnson, Muscatine and Shelby counties and Harlan, Coralville, Iowa City and North Liberty have adopted a radon appendix (trade-group list).

Iowa Radon Hotline 1-800-383-5992 (8:30–4:30 CT), low-cost test kits. Radon program 515-281-4928.

Yes. “Any person working on a radon project or in a radon occupation in Nebraska must obtain a license,” for individuals (measurement or mitigation specialist) and businesses. DHHS has a free online license lookup. How to check one →

On the state disclosure form. The seller disclosure statement asks about radon gas (yes / no / don't know), asks for copies of any test results, and asks whether the home has been mitigated and when. Testing itself is not required.

No statewide rule found. The most recent explicit statement we found is a 2018 news report: no requirements for radon testing in Nebraska schools. Nebraska is not in the 2025 national list of states that require school testing.

No statewide rule found. Nebraska is not among the states a national radon trade group lists as requiring child-care testing.

No statewide rule found. A 2025 bill (LB506) proposed radon notices for tenants; we found no record of it becoming law.

Required statewide since Sept. 1, 2019. Regularly occupied new construction must be radon-resistant: sealed sump lids, a labeled passive vent pipe from under the slab out through the roof, and a wired circuit where a fan could go. Exceptions: designs by a licensed architect or engineer, counties the state finds average below 2.7 pCi/L, and some non-residential buildings.

Nebraska Radon Program 1-800-334-9491; DHHS radon program 402-471-0386.

Yes, since July 1, 2022. All radon measurement and mitigation must be done by a professional licensed through DORA's Office of Radon Professionals. How to check one →

Warning and disclosure required. Since Aug. 7, 2023 (SB23-206), every home sale contract carries a radon warning and sellers must disclose what they know; CDPHE's radon brochure is required for sales and rental agreements. Testing itself is not required. Our full explainer →

Testing required (6 CCR 1010-6 §6.8.4(A)), with results kept on file for disclosure on request, not published. Colorado school radon records →

Testing required for licensed child care within 6 months of occupancy (6 CCR 1010-7 §7.14.2(H), effective April 14, 2025). Details →

Lease rules apply. SB23-206 also covers residential leases, with a narrower tenant remedy from Jan. 1, 2026. Details → Low-income homeowners may qualify for state mitigation assistance (up to 100% of cost, per Larimer County).

No statewide rule found. Colorado has no statewide building code. Local codes vary: Boulder, Longmont, Louisville, Erie, Superior and unincorporated Boulder County require radon-resistant construction in new single-family homes, and a trade-group list (as of Sept. 2021) names about 40 cities and 19 counties with a radon appendix, including Denver, Fort Collins, Lakewood and Durango. Check with your building department.

CDPHE radon program (free test kits while supplies last): cdphe.colorado.gov/hm/radon. Licensing questions: DORA, 303-894-7800.

Yes, since 2011. Everyone performing radon testing or mitigation in Kansas must be certified by KDHE. How to check one →

Contract language required. Every residential sale contract must include state-set radon language (K.S.A. 58-3078a): radon can be a health hazard, the seller's disclosure duty, and KDHE's recommendation to test before buying. Testing itself is not required.

No statewide rule found. None on KDHE's radon laws page, and Kansas isn't in the 2025 national list of school-testing states.

No statewide rule found. Kansas is not among the states a national radon trade group lists as requiring child-care testing.

No statewide rule found. We found no city rental rule either.

No statewide rule found. Several cities and counties adopted the radon appendix of the residential code, including Olathe (confirmed in its code), Lawrence, Topeka, Manhattan, Lenexa, Salina and Shawnee and Douglas counties (trade-group list). Check with your building department.

KDHE radon outreach 800-693-5343; KDHE health physicists 785-296-1568.