What Illinois radon law actually requires — and what it doesn’t
Almost every argument about radon in an Illinois house turns on one confusion: whether a thing is required by statute, recommended by an agency, or simply what people around here tend to do. Those are three different answers with three different consequences. This page separates them, one proposition at a time, and shows the source behind each.
Free to read, free to link, free to quote with attribution. If a classification here is wrong, tell us — corrections are recorded, not quietly edited.
How to read this page
Every statement below carries one of four labels. They are not stylistic — a statement cannot be moved between them without changing what is being claimed, and the labels are enforced in this site’s source code rather than applied by hand.
- Illinois law requires
- An Illinois statute imposes this duty. Failing to do it is a failure to comply with the Act cited.
- Illinois law does not require
- No Illinois statute imposes this. It may still be a good idea, and it is frequently agreed in a contract — but it is not the law doing the requiring.
- Agency recommendation
- A government agency recommends it. A recommendation is not enforceable and does not become law because a number is exceeded.
- Common practice — not a rule
- Radon Connect’s observation of ordinary practice, published under our editorial standards. It is neither law nor agency guidance, and is labelled so you can discount it accordingly.
Three Acts do the statutory work in Illinois. The Radon Industry Licensing Act (420 ILCS 44) governs who may perform radon measurement and mitigation for compensation. The Radon Awareness Act (420 ILCS 46) governs what a seller must disclose, and — since 1 January 2024, through its Section 25 — what a landlord must hand a tenant and what that tenant may do about a result. The Radon Resistant Construction Act (420 ILCS 52) governs how new homes are built. None of the three requires anybody to test an existing house, and none requires anybody to fix one.
The whole position, in one paragraph
Written to be quoted. Copy it as it stands, with attribution to Radon Connect and a link back so a reader can reach the sources and any later correction.
Illinois radon duties sit in three Acts, and none of them requires anybody to test or to fix an existing house. The Radon Industry Licensing Act (420 ILCS 44) reserves radon measurement and mitigation for compensation to IEMA-OHS licensees. Measurement and mitigation are licensed separately, the licence is statewide, and there is no county radon licence.
The Radon Awareness Act (420 ILCS 46) requires a residential seller to supply the state radon pamphlet and disclose known radon information. Since 1 January 2024, its Section 25 requires a lessor of a dwelling unit below the third storey to supply IEMA-OHS’s tenant pamphlet, the tenant disclosure form, and any records indicating a radon hazard. A tenant has 90 days to test at their own expense, 10 days to report the result, and may terminate the lease if that result is above the action level and the lessor elects not to mitigate.
The Radon Resistant Construction Act (420 ILCS 52) has required passive radon-resistant construction in new Illinois homes since 1 June 2013 — a built-in pathway, not a working system. EPA’s 4 pCi/L figure is a federal health recommendation, not an Illinois legal trigger.
Illinois law requires
An Illinois statute imposes this duty. Failing to do it is a failure to comply with the Act cited.
| The question | The answer | Status | Source |
|---|---|---|---|
| Can anyone test my house for radon and charge me for it? Radon professionals | A person who performs radon measurement services for compensation in Illinois must hold a radon measurement licence issued by IEMA-OHS. | Illinois law requires | Radon Industry Licensing Act (420 ILCS 44) |
| Can a general contractor install my radon system? Radon professionals | A person who performs radon mitigation services for compensation in Illinois must hold a radon mitigation licence issued by IEMA-OHS. Radon mitigation is a licensed specialty here, not general construction work. | Illinois law requires | Radon Industry Licensing Act (420 ILCS 44) |
| My tester says they can also do the mitigation. Is that one licence? Radon professionals | Measurement and mitigation are separate Illinois licences. Holding one does not authorise the other, so a licence number on a quote has to be checked for the category of work being quoted. This is the check most often skipped: the number is produced, nobody asks which licence it is. | Illinois law requires | Radon Industry Licensing Act (420 ILCS 44) |
| What does a seller actually have to hand over? Residential sale | A seller of residential property in Illinois must provide the buyer with the state radon pamphlet under the Illinois Radon Awareness Act. | Illinois law requires | Illinois Radon Awareness Act (420 ILCS 46) |
| If I know my basement tested at 6, do I have to say so? Residential sale | A seller must disclose radon information known to them, including known elevated results and prior testing information, under the Illinois Radon Awareness Act. The duty attaches to what the seller knows. It is a reason to keep the test report, the scope and the post-mitigation retest together in one folder. | Illinois law requires | Illinois Radon Awareness Act (420 ILCS 46) |
| I rent the unit out. Does any of this reach me? Rental property | For a lease, renewal or extension entered into on or after 1 January 2024, an Illinois lessor must give the prospective tenant three things: IEMA-OHS’s “Radon Guide for Tenants” pamphlet, the “Disclosure of Information on Radon Hazards to Tenants” form, and copies of any records or reports the lessor has that indicate a radon hazard in that dwelling unit. Section 25 of the Radon Awareness Act. The pamphlet and the form are IEMA-OHS documents with fixed wording; a landlord’s own summary is not a substitute for either. Both are published on the agency’s lessors-and-tenants page. | Illinois law requires | Illinois Radon Awareness Act (420 ILCS 46) |
| Can my landlord stop me testing? Rental property | An Illinois tenant may have the dwelling unit tested at the tenant’s own expense, and has 90 days from the start of the leasing period to do so. A tenant who tests must give the lessor copies of the results within 10 days of receiving them. A tenant may still test after the 90 days; what changes is the remedy attached to the result, not the right to measure. | Illinois law requires | Illinois Radon Awareness Act (420 ILCS 46) |
| The unit tested high and my landlord won’t fix it. Am I stuck? Rental property | Where a tenant’s test inside the 90-day window returns a result above the radon action level IEMA-OHS publishes, and the lessor elects not to mitigate the hazard, the tenant may terminate the lease under Section 25. This is the only place in Illinois radon law where an elevated reading attaches to a remedy rather than to a disclosure. It belongs to the tenant, it runs off the tenant’s own test, and a test run after the 90-day window does not carry it. | Illinois law requires | Illinois Radon Awareness Act (420 ILCS 46) |
| There is a capped white pipe in my new build. Was that required? Any Illinois home | New residential construction in Illinois must include passive radon-resistant construction, under the Radon Resistant Construction Act, which took effect on 1 June 2013. Passive means a pathway built in, not a system switched on. The pipe is groundwork for mitigation, and a house with one still has to be tested to know what it reads. | Illinois law requires | Illinois Radon Resistant Construction Act (420 ILCS 52) |
Illinois law does not require
No Illinois statute imposes this. It may still be a good idea, and it is frequently agreed in a contract — but it is not the law doing the requiring.
| The question | The answer | Status | Source |
|---|---|---|---|
| Does my county or village issue its own radon licence? Radon professionals | Illinois licenses radon professionals at state level through IEMA-OHS, and the licence is valid statewide. There is no county or municipal radon licence to look for, and a contractor from another part of Illinois needs no additional radon credential to quote your home. Commonly believed instead: That a contractor must be licensed in, or based in, the county where the house sits. Building permits are a separate question decided locally — see the practice note below on slab penetrations and electrical work. | Illinois law does not require | Radon Industry Licensing Act (420 ILCS 44) |
| Does the 2024 lease rule reach every unit in my building? Rental property | Illinois does not extend Section 25’s disclosure duties to dwelling units at or above the third storey above ground level. The provisions reach the units below that line. Commonly believed instead: That the 2024 rental disclosure duty applies to every apartment in a multi-storey building. The line follows how radon behaves rather than how buildings are managed: the gas enters from the soil, so exposure concentrates in the units nearest it. | Illinois law does not require | Illinois Radon Awareness Act (420 ILCS 46) |
| Did the 2024 rules make radon testing compulsory for landlords? Rental property | No Illinois statute obliges a lessor to test a rental dwelling for radon, and none obliges a lessor to mitigate one. Section 25 governs what must be handed over and what a tenant may do about a result — it does not order anyone to measure or to fix. Commonly believed instead: That the 2024 changes introduced a testing or mitigation obligation for Illinois rental property. A lessor who has never tested has no records to hand over on that point. The pamphlet and the disclosure form are still owed. | Illinois law does not require | Illinois Radon Awareness Act (420 ILCS 46) |
| So does the builder’s pipe mean my house is already protected? Any Illinois home | A passive rough-in is not a mitigation system and Illinois does not treat it as one. Adding the fan that turns it into an active system is radon mitigation, and the Radon Industry Licensing Act reserves that work to a licensed mitigation professional. Commonly believed instead: That a new Illinois home with a radon pipe has been mitigated and does not need testing. The pipe usually makes activation cheaper than a retrofit, which is the practical reason to find out whether yours is capped or running. | Illinois law does not require | Radon Industry Licensing Act (420 ILCS 44) |
| Do I have to test before I list? Residential sale | The Illinois Radon Awareness Act does not require a seller to test for radon. The duty is to provide the pamphlet and to disclose what is known — a seller who has never tested has nothing to disclose on that point. Commonly believed instead: That Illinois requires a radon test before a residential sale can close. | Illinois law does not require | Illinois Radon Awareness Act (420 ILCS 46) |
| The test came back at 5.2. Am I legally obliged to fix it? Residential sale | The Illinois Radon Awareness Act does not require a seller to mitigate. A result at or above 4 pCi/L does not, by itself, create a legal obligation to install a system in an Illinois home sale. Commonly believed instead: That crossing EPA’s 4 pCi/L action level converts a recommendation into a legal repair obligation. What happens next is contractual, not statutory: the parties negotiate a fix, a credit, or neither, the same way they handle any other inspection finding. | Illinois law does not require | Illinois Radon Awareness Act (420 ILCS 46) |
| Is there a legally required remedy once radon is disclosed? Residential sale | Illinois does not prescribe a remedy for an elevated result in a residential sale. Disclosure is the statutory step; the response is allocated by the contract between the parties. Commonly believed instead: That once radon is on the disclosure, a seller is required to resolve it before closing. | Illinois law does not require | Illinois Radon Awareness Act (420 ILCS 46) |
Agency recommendation
A government agency recommends it. A recommendation is not enforceable and does not become law because a number is exceeded.
| The question | The answer | Status | Source |
|---|---|---|---|
| What is the four-picocurie number, legally? Any Illinois home | EPA recommends taking action at radon levels of 4 pCi/L or higher, and suggests considering action between 2 and 4 pCi/L. These are health-based federal recommendations, not Illinois law. | Agency recommendation | Radon |
| How should the test be run? Any Illinois home | EPA advises starting with a short-term test on the lowest lived-in level of the home under closed-building conditions. | Agency recommendation | A Citizen’s Guide to Radon |
| How do I know the system worked? Any Illinois home | EPA advises a post-mitigation test to confirm the installed system actually reduced the level, rather than relying on the installation alone. | Agency recommendation | Consumer’s Guide to Radon Reduction |
| My county is EPA Zone 1. Does that mean my house is high? Any Illinois home | EPA’s radon zones are a predicted-average planning category for a county, and much of northern Illinois falls in Zone 1. The map is a reason to test, not a prediction about any individual address, and a Zone 3 county still contains elevated houses. | Agency recommendation | EPA Map of Radon Zones |
| Where do I check whether a licence is real and current? Any Illinois home | IEMA-OHS is the authoritative source for Illinois licence verification, the state radon pamphlet, testing guidance, and listings of licensed measurement and mitigation professionals. Verify with the agency rather than with the contractor’s own website — including for any contractor introduced through this platform. | Agency recommendation | Illinois Emergency Management Agency and Office of Homeland Security — Radon Program |
| Does the State think rental property should be tested? Rental property | IEMA-OHS recommends that all rental properties be tested and that radon hazards be mitigated where elevated levels are found, and publishes the tenant pamphlet and tenant disclosure form the rental provisions run on. Worth separating from the row above it: the agency’s position on testing rental property is broader than the duty the statute creates. | Agency recommendation | IEMA-OHS — Lessors and Tenants (radon) |
| When in a transaction should radon be dealt with? Residential sale | EPA’s guide for home buyers and sellers addresses testing during a sale and the negotiation that follows an elevated result, and is the federal reference point for transaction timing. | Agency recommendation | Home Buyer’s and Seller’s Guide to Radon |
Common practice — not a rule
Radon Connect’s observation of ordinary practice, published under our editorial standards. It is neither law nor agency guidance, and is labelled so you can discount it accordingly.
| The question | The answer | Status | Source |
|---|---|---|---|
| Is radon part of the home inspection? Residential sale | A radon measurement is generally not bundled into a standard home inspection and has to be requested separately. Buyers who assume it is included sometimes close without ever seeing a number. | Common practice — not a rule | Radon Connect editorial — no external authority |
| Does the state permit the installation? Any Illinois home | Illinois regulates the contractor through IEMA-OHS licensing. Whether the slab penetration and the dedicated electrical circuit require a building permit is decided by the local city or county building authority, so the written scope should name who obtains and pays for anything required. | Common practice — not a rule | Radon Connect editorial — no external authority |
| What belongs on a mitigation quote here? Any Illinois home | A complete Illinois mitigation quote names suction-point count and locations, the routing path, fan make and model with placement, sealing scope, a manometer, electrical responsibility, warranty terms, the post-mitigation verification test, and the contractor’s IEMA-OHS licence number. A quote missing those is incomplete rather than cheaper. | Common practice — not a rule | Radon Connect editorial — no external authority |
What this page deliberately does not state
A reference is worth citing because it is reliable, and the fastest way to stop being reliable is to restate a figure that changes without telling anyone. These are routed to the agency instead:
- Illinois radon licence fees, renewal periods, application requirements, examination details, or the contents of the state listing. These change and cannot be re-verified from our build environment. IEMA-OHS is the authoritative source for all of them.
- Subsection lettering, and section numbers other than Section 25 of the Radon Awareness Act. We name the Acts and describe the duties they impose. Section 25 is the one exception, because its 2024 commencement date, its 90-day window and its 10-day reporting deadline are the whole content of the rule — a reader with a clock running needs to be able to look them up, so the section is named.
- Any local ordinance. Illinois radon licensing is statewide, but permitting, inspection and rental rules vary by municipality and we do not survey them.
- What any individual home will measure. No map, county designation, or neighbouring result substitutes for testing the address in question.
How this page is verified
Every proposition on this page carries the source it rests on, and each source is linked in full below. Two different verification methods are in play, and we would rather say which is which than let one borrow the other’s credibility.
The licensing and residential-sale rows restate material already published and reviewed on this site. The rental rows (Section 25 of the Radon Awareness Act), the new-construction row, and the per-Act links were established during the August 2026 revision from search results returning the General Assembly’s and IEMA-OHS’s own pages, corroborated across independent professional summaries. Our build environment cannot open a web page directly, so no source here was read by us in a browser.
Where a fact changes quietly, such as a fee or a form, we route you to the agency rather than repeat it. If you find a classification here that no longer matches the source, tell us and we will correct it and record the change.
Our wider rules for what may be claimed and which source may support it are published at citation standards and editorial policy. What we can and cannot establish without visiting a property is set out at what we can determine.
Where to go next
If you are inside a transaction, the mechanics of timing, contingency windows and negotiation are covered in radon in an Illinois home sale. If you are checking a contractor, the licence categories and the verification steps are set out in licensed radon contractors in Illinois. For the agency directory — who answers which question — see the Illinois resource centre. If you have a number and want to know what it means before anything else, radon levels explained is the place to start.
Questions this page gets asked
Does Illinois require a radon test before selling a house?
No. The Illinois Radon Awareness Act requires a seller to provide the state radon pamphlet and to disclose radon information they know about. It does not require testing, and it does not require mitigation. A buyer may of course make testing a condition of their offer — that is a contract term, not a statutory one.
If a test comes back above 4 pCi/L, does Illinois law require the seller to fix it?
No. 4 pCi/L is EPA’s recommended action level — a federal health recommendation. No Illinois statute converts an elevated result into an obligation to mitigate in a residential sale. What happens next is negotiated between the parties like any other inspection finding.
What do Illinois landlords have to disclose about radon since 2024?
For a lease, renewal or extension entered into on or after 1 January 2024, Section 25 of the Illinois Radon Awareness Act requires the lessor of a dwelling unit below the third storey above ground level to provide IEMA-OHS’s “Radon Guide for Tenants” pamphlet, the “Disclosure of Information on Radon Hazards to Tenants” form, and copies of any records or reports indicating a radon hazard in that unit. It does not require the lessor to test the unit, and it does not require the lessor to mitigate.
Can an Illinois tenant break the lease over a high radon result?
In one specific situation. A tenant has 90 days from the start of the leasing period to test the unit at their own expense, and must give the lessor copies of the results within 10 days of receiving them. If that result is above the radon action level IEMA-OHS publishes and the lessor elects not to mitigate the hazard, Section 25 allows the tenant to terminate the lease. A test run after the 90-day window does not carry that remedy.
Does a radon contractor need a county licence in Illinois?
No. Illinois licenses radon measurement and mitigation professionals at state level through IEMA-OHS, and the licence is valid statewide. There is no county or municipal radon licence. Building permits for the slab penetration or the electrical circuit are decided locally, which is a separate question from the radon licence.
Is the measurement licence the same as the mitigation licence?
No — they are separate Illinois licences and holding one does not authorise the other. When a licence number appears on a quote, the thing to confirm is that it covers the category of work being quoted, and that it is current. IEMA-OHS is where you check.
Can I reuse this page?
Yes. Quote it, link to it, or hand it to a client. We ask only for attribution to Radon Connect and a link back so a reader can see the sources and any later correction. If you spot an error, tell us — corrections are recorded on the page rather than made silently.
Sources
- Illinois General Assembly — Radon Industry Licensing Act (420 ILCS 44)
- Illinois General Assembly — Illinois Radon Awareness Act (420 ILCS 46)
- Illinois General Assembly — Illinois Radon Resistant Construction Act (420 ILCS 52)
- U.S. EPA — Radon
- U.S. EPA — A Citizen’s Guide to Radon
- U.S. EPA — Consumer’s Guide to Radon Reduction
- U.S. EPA — EPA Map of Radon Zones
- IEMA-OHS — Illinois Emergency Management Agency and Office of Homeland Security — Radon Program
- IEMA-OHS — IEMA-OHS — Lessors and Tenants (radon)
- U.S. EPA — Home Buyer’s and Seller’s Guide to Radon
All three Acts sit in Chapter 420 of the Illinois Compiled Statutes — Act 44 (Radon Industry Licensing Act), Act 46 (Radon Awareness Act) and Act 52 (Radon Resistant Construction Act) — and each source above now links to that Act on the General Assembly’s own site rather than to the Compiled Statutes index. Those per-Act addresses were established from search results returning the Assembly’s own pages; we cannot open a web page from our build environment, so if one of them fails to resolve for you, tell us and we will correct it.