Gathering existing radon-test results for a seller discussion
A practical guide for Illinois sellers on organizing and presenting radon test data to facilitate transparent and informed real estate discussions.
The short answer
To discuss radon with potential buyers, you must gather all historical testing results and verify that the work was performed by an IEMA-OHS licensed professional. If results exist, provide them alongside the mandatory disclosure documents to maintain transparency and ensure you are only sharing accurate, professional data as required by the Illinois Real Property Disclosure Act.
Compiling Test Records
Start by gathering every radon report you have received for the property. These reports form the basis of your knowledge regarding the potential radon hazard.
Decision Worksheet: Create a chronological list of all radon tests performed on the property, noting the date of the test and the service provider.
Verifying Professional Licensing
Only results from licensed professionals carry the weight needed for credible disclosure. Reports from unlicensed individuals may not be reliable under Illinois law.
Planning Example: Check the past reports for the name and license number of the testing firm. Use the IEMA-OHS portal to confirm those licenses were active at the time of testing.
Communicating Test Outcomes
Transparency is key. You are not required to conduct new tests to fill out a report, but you must disclose any known material defects, including high radon levels.
Decision Worksheet: Draft a summary note for the buyer that explains the test results simply, such as 'Testing conducted on [Date] by [Licensed Professional] indicated [Result].'
Understanding Potential Mitigation
If your past tests showed high levels, check if any mitigation systems were installed. If a system exists, it also needs to be disclosed.
Planning Example: Contact the company that installed the system to obtain a record of the installation, which helps confirm the property has been addressed.
Checklist
- Collect all past radon testing reports.
- Verify all reports were created by an IEMA-OHS licensed professional.
- Identify if any mitigation systems were installed at the property.
- Attach copies of professional test results to your disclosure materials.
- Consult with a professional if you have doubts about report validity.
Common questions
Am I required to pay for a new radon test if my old one is several years old?
The law does not require you to perform a new investigation, but old results should be shared if they are part of your actual knowledge.
What if I don't have any past radon test results?
You are not required to conduct a test. If you have no knowledge of radon issues, you should state that honestly on the disclosure form.
Sources
- Illinois Residential Real Property Disclosure ActChecked October 12, 2026
- Illinois Condominium Property Act — 2025 editionChecked October 12, 2026
- IEMA-OHS — Real estate radon guidanceChecked October 12, 2026
- EPA — Real estate lead-hazard disclosuresChecked October 12, 2026
This guide is general educational content from SQFT IO, prepared with AI assistance. It is not legal, tax or loan advice. Talk with a licensed attorney, tax professional or lender about your situation. SQFT IO Illinois license 478.027617.