Radon Testing Requirements in Idaho
Radon Testing Requirements in Idaho
Idaho doesn’t require radon testing for homes, home sales or rentals. The state’s property disclosure form doesn’t name radon specifically, though it does ask sellers whether they know of any hazardous materials on the property. Idaho also doesn’t require radon-resistant construction unless a city or county has adopted it. Testing is voluntary, but the Idaho Department of Health and Welfare (DHW) estimates that about 2 in 5 Idaho homes have elevated radon and recommends testing every home. This article explains what Idaho requires, what it doesn’t and how to get your home tested.
Is radon testing required in Idaho?
No. We found no Idaho law that requires homeowners, sellers, buyers, landlords or lenders to test for radon. The state’s approach is education and access to low-cost testing through DHW’s radon program.
That doesn’t mean radon is rare. DHW reports that 2 out of 5 Idaho homes have radon above the EPA action level of 4 pCi/L. The EPA recommends fixing homes at or above that level and considering action between 2 and 4 pCi/L. No radon level is considered completely safe, and long-term exposure causes lung cancer. Because radon varies from house to house, testing is the only way to know your home’s level. Our article on whether radon maps are useful or misleading explains why a ZIP code or county result can’t stand in for your own test.
Radon and Idaho home sales
Idaho’s Property Condition Disclosure Act requires anyone transferring residential real property with one to four dwelling units to complete a disclosure form, with some exemptions. The form lists specific questions set out in state law. It doesn’t mention radon by name. The closest question asks whether the seller is aware of any hazardous materials or pest infestations on the property.
Whether a known radon result falls under that question isn’t spelled out in the statute. A seller who has a test result showing elevated radon may choose to disclose it, and a buyer can ask directly. If you’re unsure how a known radon result should be handled on the form, an Idaho real estate attorney can advise you. The disclosure reflects only the seller’s actual knowledge and isn’t a warranty, so a seller who has never tested has nothing to report.
Idaho law also gives buyers a short window, three business days after receiving the disclosure form in certain situations, to rescind the transfer agreement in writing. That rescission right is tied to the disclosure form generally, not to radon specifically.
Testing during an Idaho home purchase
DHW encourages buyers to request a radon test during the home inspection and to negotiate mitigation if levels are elevated. A short-term test fits a typical inspection period. Many buyers hire a certified measurement professional so the result is less likely to be disputed. If a test comes back high, common solutions include a price credit, a repair before closing or an escrow holdback for mitigation. Our guide for real estate agents on radon covers how testing fits into a sale.
Rentals and new construction in Idaho
We found no Idaho law requiring landlords to test rental units for radon or to disclose radon results to tenants. Renters who want to know their level can test their unit themselves, ideally after discussing it with their landlord.
For new homes, DHW notes that radon control methods aren’t required by law in Idaho unless a city or county has specifically adopted them. Some builders add radon-resistant features voluntarily, such as a gas-permeable layer under the slab and a passive vent pipe that can be converted to an active system later. Our article on radon-resistant new construction explains how those features work. If you’re building or buying a new home, ask the builder what was installed, and test after you move in.
How to get a radon test in Idaho
Idaho offers several ways to test, some of them free:
- Free DHW test kits. DHW provides one free test kit per address every two years when supplies are available. Kits have sometimes been out of stock, so check the program’s website.
- Library lending program. The Idaho Radon Library Lending Program lets residents check out free test devices from participating public libraries around the state.
- Discounted or retail kits. DHW points residents to discounted kits through a partner lab, and kits are also sold at hardware and home improvement stores.
- Professional testing. A certified measurement professional can run the test for you, which is common in real estate transactions.
For a valid result, place the test in the lowest lived-in level of your home, away from drafts, heat sources, high humidity and exterior walls. Keep windows and exterior doors closed for at least 12 hours before the test and throughout it, except for normal entry and exit. Radon tends to run higher during the heating season, which our guide to radon testing in winter vs. summer explains.
Our radon testing guide walks through the process, our radon test kit comparison covers kits and monitors and our article on what 4.0 pCi/L actually means explains how to read a borderline result.
Radon readings reported in Idaho
Idaho homeowners have submitted 62 radon readings to RadonResources.com, from places including Idaho Falls, Hailey, Post Falls, Moscow and Coeur d’Alene. About 9 in 10 were at or above 4 pCi/L. That’s much higher than DHW’s statewide estimate, because people with elevated results are more likely to look for information and share them. The data can’t predict your home’s level, but it shows that high readings turn up across the state. You can browse radon readings homeowners have reported or visit our Idaho radon page for local professionals.
Hiring a radon professional in Idaho
Idaho doesn’t run its own licensing program for radon testers or mitigators. DHW directs residents to professionals certified by the National Radon Proficiency Program (NRPP) or the National Radon Safety Board (NRSB). Without a state license to check, national certification is the best way to confirm a contractor has radon-specific training.
The most common fix for elevated radon is active soil depressurization, a vent pipe and fan system that draws radon from beneath the foundation and releases it above the roof. Sealing cracks helps the system work, but sealing alone is usually not a dependable fix for significantly elevated radon. After installation, a post-mitigation test confirms whether the system lowered the level. Our guide to hiring a certified radon mitigator and our radon contractor checklist list the questions to ask, and our article on what to do when a post-mitigation test fails covers the next steps if levels stay high.
Frequently asked questions
Do Idaho sellers have to disclose radon?
Idaho’s disclosure form doesn’t name radon. It asks whether the seller is aware of any hazardous materials on the property, and the statute doesn’t say whether radon counts. Sellers with a known elevated result may choose to disclose it, and buyers can ask directly. For a definite answer about a specific sale, consult an Idaho real estate attorney.
How do I get a free radon test kit in Idaho?
The Idaho Department of Health and Welfare offers one free test kit per address every two years when kits are available. You can also borrow a test device through the Idaho Radon Library Lending Program at participating libraries. For help, contact DHW at 800-445-8647 or [email protected].
Does Idaho require radon-resistant construction in new homes?
Not statewide. DHW says radon control methods aren’t required by law unless a city or county has specifically adopted them. Check with your local building department to see whether your area has adopted radon provisions, and test any new home after you move in.
Do Idaho landlords have to test for radon?
We found no Idaho law requiring landlords to test rentals or disclose radon results to tenants. Tenants can test their own units with a kit from DHW, a library or a store. If a test comes back elevated, share the result with your landlord and ask about mitigation.
Testing is up to you in Idaho
Idaho leaves radon testing to homeowners, buyers and renters, while making it easy and inexpensive to do. With about 2 in 5 homes estimated to be above the EPA action level, a test is a practical step for any Idaho household. If you’d like help testing or addressing a high result, you can connect with a certified radon professional in Idaho.
Sources and further reading
- Idaho Department of Health and Welfare, What Is Radon? (2 in 5 homes elevated, free kits, library lending, building rules, NRPP and NRSB professionals, contact information).
- Idaho Code, Section 55-2504 (who must provide a property condition disclosure).
- Idaho Code, Section 55-2508 (disclosure form questions, including hazardous materials).
- Idaho Code, Section 55-2515 (buyer rescission within three business days).
- U.S. Environmental Protection Agency, A Citizen’s Guide to Radon (action levels, testing guidance).
- RadonResources.com user-submitted radon readings (self-reported and not a representative sample).
This article is for general educational purposes and is not legal or medical advice. Laws and program details can change, and local rules may differ from state law. Consult an Idaho real estate attorney for legal questions and a certified radon professional for testing or mitigation.
