Interactive tool
Should I test my home for radon?
The honest answer is that testing is inexpensive and the result is unknowable any other way, so the bar for "worth doing" is low. But the reasons differ in urgency, and which one applies to you changes what kind of test to run.
This tree returns your reason and the matching test type. It does not tell you your house is at risk — nothing can, short of a measurement.
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.
Yes
By you or by a previous owner, with a result you have seen.
A transaction sets a deadline and needs a defensible measurement.
Yes
Or a lower-level bedroom is planned.
Yes
Finishing converts the strongest soil-contact area into living space.
Yes
Recent construction may include a passive rough-in.
Yes
Useful as a prompt, not as a prediction.
Yes
EPA describes radon and smoking as compounding risks.
What this indicates
Reading your inputs…
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 |
|---|---|---|
| This home has been tested before | No | By you or by a previous owner, with a result you have seen. |
| Buying or selling now | Neither | A transaction sets a deadline and needs a defensible measurement. |
| Someone sleeps on the lowest level | No | Or a lower-level bedroom is planned. |
| Planning to finish the basement | No | Finishing converts the strongest soil-contact area into living space. |
| Built in the last ten years | No | Recent construction may include a passive rough-in. |
| A nearby home tested high | No | Useful as a prompt, not as a prediction. |
| Someone in the household smokes | No | EPA describes radon and smoking as compounding risks. |
What we took on trust
- Your answers about buying or selling now are taken as described. Where a description is approximate the output is approximate in the same way.
- The yes/no conditions (this home has been tested before, someone sleeps on the lowest level, planning to finish the basement, built in the last ten years, a nearby home tested high, someone in the household smokes) 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
- Whether your specific house has elevated radon. Nothing on this platform can answer that without a measurement.
- How much any single factor raises the probability of an elevated result, because we hold no measurement data linking house characteristics to outcomes.
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
- A large paired dataset of house characteristics and measured results would establish which building features actually predict elevated radon. Published work is mostly at county aggregate level, which cannot answer an address-level question.
- Measured exposure differences between finished and unfinished lower levels in the same houses would quantify what the lowest-lived-in-level convention conservatively assumes.
- 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 |
|---|---|
| This home has never been tested | Test. A never-measured house has an unknown result, and no characteristic of the building — age, construction, location, or a neighbour’s number — substitutes for measuring it. A short-term kit on the lowest lived-in level under closed-building conditions is the starting point. |
| Buying | Test during the inspection period, and order it at the start rather than the end. Test even if the house already has a mitigation system: an installed system proves an owner acted once, not that it works today. |
| Selling or 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 late in a contingency is a concession under time pressure. |
| Someone sleeps on the lowest level | Test, and treat the result as more consequential than the same number in a storage basement. Exposure tracks hours spent in the space, and sleeping hours are the largest single block. |
| Planning to finish the basement | Test before the framing goes up. An open basement gives an installer free choice of suction location at the lowest cost, and finishing over a verified slab settles the question permanently. |
| Built in the last ten years | Test, and check the attic for a labelled PVC riser first. Radon-resistant construction reduces levels in many houses and is insufficient in others; if a passive rough-in exists, any needed remedy is usually activation rather than a retrofit. |
| A nearby home tested high | Treat that as a prompt, not a prediction. Soil permeability under your own footprint, your slab penetrations, and your pressure balance all differ, and houses on the same street routinely land on opposite sides of the action level. |
| Someone in the household smokes | The case for measuring is stronger. EPA describes radon and smoking as compounding risks, which raises what is at stake in the 2–4 consideration band where the decision is otherwise a judgement call. |
| Already tested and none of the above applies | No new reason to test right now. Note the date of your last result and use the retest tool, which covers the interval and the change-based triggers. |
What this tool cannot do
- This tool tells you whether a reason to test applies. It cannot tell you whether your house has elevated radon — that is what the test is for.
- It does not know your local geology, and would not use it if it did: EPA zone maps describe counties, not addresses.
- It makes no health assessment for any individual. That belongs with a physician.
Related
- Should I retest? — Time since the last test, plus what has changed in the house — the two things that decide it.
- What does my result mean? — Your number, read against guidance and against the conditions it was measured in.
- Should I mitigate? — Above the action level it is recommended. In the 2–4 band it is your call, and this shows what tips it.
- How testing works — Devices, placement, closed-building conditions, and what invalidates a result.
- When to retest — Every two years, plus after anything that changes how the house meets the soil or how it moves air.
- Finished basements — A finished basement raises both the exposure and the cost of fixing it — which is why the timing question matters more than the technique.
- Radon Testing Method Comparison Dataset — Which method answers which question — and which decisions each one cannot carry.
- Radon Terminology Dataset — Controlled vocabulary with the misreading each term reliably attracts.
- 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.
- Indoor radon cannot be inferred from building age, construction type, location, or a neighbour’s result. Measurement is the only way to know, and that is a settled position in published guidance.
- EPA describes radon and smoking as compounding risks, which is why the tool weights a smoking household.
- Radon-resistant construction reduces levels in many houses and is insufficient in others, so a recent build is a reason to test rather than a reason not to.
- What we do not knowQuestions you may reasonably have that this page does not answer.
- Whether your specific house has elevated radon. Nothing on this platform can answer that without a measurement.
- How much any single factor raises the probability of an elevated result, because we hold no measurement data linking house characteristics to outcomes.
- What research would settle itWhat it would actually take to answer the above — naming it is the difference between honesty and hedging.
- A large paired dataset of house characteristics and measured results would establish which building features actually predict elevated radon. Published work is mostly at county aggregate level, which cannot answer an address-level question.
- Measured exposure differences between finished and unfinished lower levels in the same houses would quantify what the lowest-lived-in-level convention conservatively assumes.
- What we do not claimClaims you might expect to find here and will not, with the reason.
- We do not claim your area, neighbourhood, or house type is high risk. We publish no radon measurements by area and would not infer risk from geology if we did.
- We do not claim a probability that your test will come back elevated, because we have no data from which to compute one.
- We do not claim testing is required. No state we serve requires a homeowner to test an existing home.
- What we cannot independently verifyFacts this page relies on that we could not confirm ourselves.
- Whether a previous owner’s test was validly conducted, or what conditions applied when it was run.
Sources
- U.S. EPA — Radon
- U.S. EPA — A Citizen’s Guide to Radon
- U.S. EPA — Health Risk of Radon
Result came back elevated?
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