Selling a home
A radon result you discover before listing is a line item you control. The same result found by a buyer’s inspector on day eight of a ten-day contingency is a concession negotiated under time pressure.
Disclosure obligations attach to what you know. Testing does not create a duty to fix — it creates a duty to be honest, which most sellers are better off with.
Before you list
Test the house under closed-building conditions — hard to reverse later
A known number with a quote attached negotiates far better than a surprise.
If a system exists, run a current test rather than relying on an old report — hard to reverse later
A test from several years ago carries far less weight with a buyer than a recent one.
If a system exists, have a contractor inspect it
Fan operation, manometer, discharge, pipe condition, and whether the design still matches the house after renovations.
If the fan is near end of warranted life, consider replacing it now
Cheap relative to the negotiation it prevents, and it lets you transfer a fresh warranty.
If the result is elevated
Get a written quote before deciding anything — hard to reverse later
It converts an open-ended concern into a bounded number.
Weigh mitigating pre-listing against crediting later
Pre-listing work is a documented improvement and you choose the contractor. A credit is faster.
If you mitigate, require the verification test before listing — hard to reverse later
Without it you have swapped one open question for another.
Assemble the folder
Installer credential number as written on the contract — hard to reverse later
The first thing a buyer or their inspector asks for.
Written scope or system diagram
Shows what is where, which matters to a future servicing contractor.
Post-mitigation verification report with its date — hard to reverse later
The document that makes the system a completed repair rather than an unknown.
Fan model, install date, and warranty terms including transferability
A transferable warranty is a genuine selling point.
The most recent test result — hard to reverse later
Recency is what gives it weight.
Disclosure and presentation
Ask your agent which disclosure form applies in your state and complete it accurately — hard to reverse later
States handle radon disclosure differently, and your agent knows which instrument applies.
Report results you hold accurately, including old ones — hard to reverse later
Disclosure attaches to what you know. Selective memory is the risk, not the number.
Mention the system factually in listing remarks: year, credential, latest verified result and date
A number and a date do more than any amount of reassurance.
Do not describe the house as safe or radon-free — hard to reverse later
No result means zero risk, buyers’ agents know it, and the overclaim invites the scrutiny you were avoiding.
Leave the system running through showings, inspections, and closing — hard to reverse later
A system switched off protects nothing, and any test run then measures an unmitigated house.
What this checklist does not cover
A checklist that pretends to be complete is worse than one that states its edges. These are the things deliberately left out, each with somewhere better to go:
- Nothing here is legal advice. Which disclosure form applies and how to complete it belong with your agent and, where warranted, an attorney.
- It does not tell you whether mitigating pre-listing pays back. We publish no valuation claims.
- It does not cover the buyer side — that is the buying checklist.
Confidence and limits of this page
Every decision resource on this platform states its own boundaries. This is not a disclaimer — it is the part of this checklist you should read before relying on it.
- What we knowClaims on this page we stand behind, each traceable to an approved source or to observable structure.
- Disclosure obligations in the states we serve attach to known radon information; none requires a seller to test or to mitigate an existing home.
- A system switched off is not reducing anything, and a test run during that period does not describe a mitigated house.
- An installed system without a verification report is an undocumented system from a buyer’s perspective.
- What we do not knowQuestions you may reasonably have that this page does not answer.
- Whether pre-listing mitigation returns its cost at sale. We publish no valuation claims and have no basis to quantify it.
- How buyers in your specific market react to a documented system versus none.
- What research would settle itWhat it would actually take to answer the above — naming it is the difference between honesty and hedging.
- A matched comparison of sale outcomes for documented-mitigated, undocumented-mitigated, and untested homes would settle whether pre-listing work pays back. We have not found that published, and it would need appraisal-level data.
- Measured buyer response to disclosure framing would establish whether factual listing remarks help or are simply neutral.
- What we do not claimClaims you might expect to find here and will not, with the reason.
- We do not claim radon mitigation increases sale price or shortens time on market by any amount.
- We do not give legal advice on disclosure completion.
- We do not claim any result is safe, and we advise against describing a house that way.
- What we cannot independently verifyFacts this page relies on that we could not confirm ourselves.
- Your state’s current disclosure form and its exact requirements. Forms are amended and we route them to your agent and the state programme.
Sources
- U.S. EPA — Radon
- U.S. EPA — Home Buyer’s and Seller’s Guide to Radon
- U.S. EPA — A Citizen’s Guide to Radon
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