Radon in a home sale: what should we do?
No state this platform serves requires a seller to test or to mitigate an existing home, which makes an elevated result a negotiated item. What decides it is contract language, local practice, leverage, and how far above the action level the number sits.
This tool works out which outcomes are realistic in your position and what belongs in writing. It is not legal advice, and where a question turns on your contract it says so and sends you to your agent.
Work it through
Everything below runs in your browser. Nothing you enter is sent to us or to anyone else — this page has no server to send it to.
Which side of the transaction.
Leave at zero if you have not tested yet.
Zero if not under contract.
From a credentialed contractor who has seen the house.
An installed active system with a fan.
What this indicates
Reading your inputs…
What is established, and what is not
Two groups, weighted the same. An item in the second group is an open question rather than a problem — most of them are the ordinary condition of a home test, and none of them is a mark against your house.
What nobody has established
Not failures, and not things you did wrong. Each one is answerable — by a laboratory, by a professional on site, or by a longer measurement — and none of them has been answered yet.
Device calibration
Not established
A device reports what it reports. Whether it was calibrated, and when, is a property of the device and its programme rather than of the reading.
Chain of custody
Not established
Where the device was between the end of the test and the analysis affects what the result describes, and only the handling record shows it.
Placement compliance
Not established
Whether placement actually met protocol depends on distances and surfaces nobody has measured from here, however carefully it was described.
Interference during the test
Not established
A door propped open for an afternoon, or a device moved and moved back, would not appear in any record a homeowner holds.
Seasonal variation in this house
Not established
The same house commonly reads differently in different seasons, and a single test covers one period rather than a year.
Readings on other floors
Not established
A measurement describes the level it was taken on. What the rest of the house reads is a separate question with a separate answer.
Categories a next step could fall into
Unordered, and none of them is a recommendation. Which one applies depends on things this page does not know.
Why this says what it says
The full working, shown rather than summarised. Nothing below is hidden behind a toggle, because reasoning that takes a click to reach has not really been shown.
What you told us, and what each answer did
| Your answer | Value | What it influences |
|---|---|---|
| You are | Buying | Which side of the transaction. |
| Result | 6 pCi/L | Leave at zero if you have not tested yet. |
| Days left in the inspection period | 7 days | Zero if not under contract. |
| A written mitigation quote is in hand | No | From a credentialed contractor who has seen the house. |
| The house already has a system | No | An installed active system with a fan. |
What we took on trust
- The figures you enter (result, days left in the inspection period) are taken exactly as typed. We have no way to check them against a device or a laboratory record.
- Your answers about you are are taken as described. Where a description is approximate the output is approximate in the same way.
- The yes/no conditions (a written mitigation quote is in hand, the house already has a system) are accepted exactly as you set them. Nobody has confirmed any of them, and the output assumes each is as stated.
What is still unknown
- How often each outcome actually occurs, in your state or anywhere. We publish the taxonomy and explicitly not a distribution.
- What your contract requires, what your deadline means, and whether an extension is available. Those are contract questions we cannot read from here.
- What a fair credit is for your house, because that comes from a written quote rather than from us.
Why this stops short of a decision
This runs entirely on what you typed. Nobody has been to your house, nobody has seen the device or the laboratory record, and the choice between courses of action follows from diagnostics performed on the building. What you have here is a reading of what you reported, which is a different thing from a decision and a good basis for making one.
What would change this
- The negotiation outcome frequency instrument in our Research Center specifies what would settle this: 300 post-closing homeowner reports coded against the published taxonomy. It holds zero observations today.
- Regional variation in radon negotiation custom has, as far as we can establish, never been measured. It is described anecdotally by agents and nowhere systematically.
- Correcting any answer above. Change an input and the output changes, which is the honest behaviour of something working from a description.
The logic, in full
These are the rules the tool applies — not a summary of them. The interactive panel above evaluates exactly this list, and a build check fails if the two ever diverge. A decision tool whose reasoning you cannot inspect is a black box, and a black box is not authority.
| When | Then |
|---|---|
| Buying and no test yet | Order it now, at the start of the inspection period rather than the end. A short-term test needs 12 hours of closed-building conditions before it starts, plus the measurement, plus time for a quote. |
| Buying and the house already has a system | Test anyway, inside the inspection period. An installed system proves an owner acted once, not that it works today. Check the manometer columns are offset and ask for the original verification report. |
| Result at or above 4.0 and no written quote | Get one before you ask for anything. A specific scope and number is a far stronger request than “please address the radon”, and it prevents a credit being set below what the work costs. |
| Fewer than five days left in the inspection period | Time is the binding constraint, not the argument. Prioritise a written quote and an extension request over a second test. |
| Buying, result elevated, quote in hand | Four outcomes are realistic: seller installs, seller credits, split, or you absorb it. Which one depends on leverage and your contract — put certified contractor, written scope, and a verification test delivered before closing into the amendment either way. |
| Selling and under contract with an elevated result | The response is negotiated, not mandated. Installing before closing with a verification test in hand is usually the cleanest resolution; a credit sized from a real quote is the faster one. |
| Preparing to list | Test before listing. A known result with a written quote attached is a line item you control; the same result found by a buyer’s inspector at day eight of a ten-day contingency is a concession under time pressure. |
| Preparing to list and the result is elevated | Mitigating pre-listing converts an open question into a documented improvement, and you choose the contractor. Keep the credential number, scope, verification result, and warranty in one folder. |
| Result in the 2.0 to 3.9 band | Guidance suggests considering action rather than requiring it. In a transaction this is usually a disclosure and negotiation question rather than a mitigation one — but a buyer may still ask, and a written quote keeps the conversation concrete. |
What this tool cannot do
- Nothing here is legal advice. What your contract requires, what a deadline means, and what happens if one is missed are questions for your agent and, where the stakes warrant, a real estate attorney.
- There is no universal rule on who pays. Regional custom varies considerably and this tool does not know your market.
- It cannot tell you what a credit should be. That comes from a written quote on the actual house.
Related
- What does my result mean? — Your number, read against guidance and against the conditions it was measured in.
- Compare two quotes — Review both bids on the eight lines that explain almost every price gap.
- Who pays — It is negotiated, not mandated. Contract language, local practice, and leverage decide it — and preparation changes the outcome more than argument does.
- Failed test during inspection — The inspection-window playbook, in the order the clock demands.
- Negotiating radon repairs — What each side actually holds, and how the deal usually lands.
- Selling with a system — An installed system helps or hurts depending almost entirely on whether you can document that it works.
- Home-Sale Radon Negotiation Outcome Taxonomy — Four outcomes, what drives each, and who carries the risk afterward.
- Home-Sale Negotiation Outcome Frequency Dataset — Instrument published, N = 0. The taxonomy exists; the distribution does not yet.
- All tools — every calculator and decision tool.
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 tool 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.
- No state this platform serves requires a seller to test or to mitigate an existing home. Disclosure obligations attach to what a seller knows.
- The four negotiation outcomes — seller installs, seller credits, split, buyer absorbs — are exhaustive of how a negotiated inspection finding can resolve.
- A short-term test needs twelve hours of closed-building conditions before it starts, plus its measurement period, plus time for a written quote. That sequence is the binding constraint in a short contingency.
- What we do not knowQuestions you may reasonably have that this page does not answer.
- How often each outcome actually occurs, in your state or anywhere. We publish the taxonomy and explicitly not a distribution.
- What your contract requires, what your deadline means, and whether an extension is available. Those are contract questions we cannot read from here.
- What a fair credit is for your house, because that comes from a written quote rather than from us.
- What research would settle itWhat it would actually take to answer the above — naming it is the difference between honesty and hedging.
- The negotiation outcome frequency instrument in our Research Center specifies what would settle this: 300 post-closing homeowner reports coded against the published taxonomy. It holds zero observations today.
- Regional variation in radon negotiation custom has, as far as we can establish, never been measured. It is described anecdotally by agents and nowhere systematically.
- What we do not claimClaims you might expect to find here and will not, with the reason.
- We do not give legal advice, and this tool routes contract questions to an agent or attorney rather than answering them.
- We do not claim a universal rule on who pays, because there is not one.
- We do not claim radon affects appraised value by any specific amount. That varies by market and appraiser and we have no basis to quantify it.
- What we cannot independently verifyFacts this page relies on that we could not confirm ourselves.
- Your contract language, your local market conditions, and your state's current disclosure form. All three bear on the answer and none is visible to us.
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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