Should I mitigate?
At or above 4 pCi/L, published guidance recommends acting, and that is the straightforward case. Between 2 and 4 the guidance says to consider action, which is a genuine judgement call — and the factors that tip it are about your household, not about the number.
This tool separates the two situations and shows what bears on the second. It will not tell you a result is safe, and it will not tell you what a system costs.
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.
From a validly conducted test on the lowest lived-in level.
Two measurements agreeing, or a long-term detector.
Exposure tracks hours spent in the space.
Longer remaining exposure years.
EPA describes radon and smoking as compounding risks.
Exposure is cumulative.
Mitigating first is materially cheaper.
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 |
|---|---|---|
| Your result | 3.2 pCi/L | From a validly conducted test on the lowest lived-in level. |
| Confirmed by a second test | No | Two measurements agreeing, or a long-term detector. |
| How the lowest level is used | Daily living space | Exposure tracks hours spent in the space. |
| Children or a pregnancy in the household | No | Longer remaining exposure years. |
| Someone in the household smokes | No | EPA describes radon and smoking as compounding risks. |
| Years you expect to stay | 10 years | Exposure is cumulative. |
| Finishing the lower level soon | No | Mitigating first is materially cheaper. |
What we took on trust
- The figures you enter (your result, years you expect to stay) are taken exactly as typed. We have no way to check them against a device or a laboratory record.
- Your answers about how the lowest level is used are taken as described. Where a description is approximate the output is approximate in the same way.
- The yes/no conditions (confirmed by a second test, children or a pregnancy in the household, someone in the household smokes, finishing the lower level soon) 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 much risk reduction you personally obtain from mitigating at a given starting concentration. That is a dose-response question we are not equipped to answer for an individual.
- Whether your reading is representative of your annual average, unless you have run a long-term detector.
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
- Individual-level risk estimates at residential concentrations, resolved finely enough to inform a decision in the 2–4 band, remain an active research area rather than a settled one. Pooled residential case-control evidence establishes direction more firmly than magnitude at the low end.
- A cost-effectiveness analysis of mitigation across the consideration band, using real quote data, would turn this judgement call into an arithmetic one. Neither the risk resolution nor the quote data currently exists for that.
- 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 |
|---|---|
| Result at or above 4.0 pCi/L | EPA recommends taking action to reduce the level. Get written quotes from credentialed contractors that include a sub-slab diagnostic and a post-mitigation verification test. |
| Result at or above 10.0 pCi/L | Well above the action level, so the decision is not close. It is still not an emergency and nobody needs to leave the house — but there is no version of this where waiting is the better option. |
| Result in the 2.0 to 3.9 band | Guidance suggests considering action rather than recommending it. This is a household judgement, and the factors below are what tip it. There is no wrong answer here that a number can identify for you. |
| Result below 2.0 pCi/L | No action is recommended. Lower is still better and some risk remains at any concentration, but there is no guidance basis for installing a system at this level. |
| Single unconfirmed short-term test near the action level | Confirm before committing. A second short-term test or a long-term detector costs a small fraction of a system, and readings near the line move with weather and season. |
| In the consideration band with daily living space below grade | Weighs toward acting. Exposure tracks hours, and a lower level in daily use is where the most hours accumulate. |
| In the consideration band with children or a pregnancy | Weighs toward acting. Exposure is cumulative over a lifetime, so more remaining years means more of it — that reasoning is about duration, not about any special vulnerability we are claiming. |
| In the consideration band with a smoking household | Weighs toward acting. EPA describes radon and smoking as compounding risks, which raises what is at stake at any given concentration. |
| In the consideration band and staying under three years | Weighs toward waiting, with two caveats: disclosure obligations attach to what you know when you sell, and a documented mitigated system reads to a buyer as a completed repair. |
| Finishing the lower level soon at any level above 2.0 | Mitigate first regardless of where you land in the band. An open basement gives the installer free choice of suction point and routing at the lowest cost, and finishing over a verified slab removes the question permanently. |
| In the consideration band, storage only, staying briefly | The weakest case for acting on this tree. A long-term detector over ninety days would tell you what you actually live with before you spend anything. |
What this tool cannot do
- This tool weighs factors. It does not compute a risk number for your household, and no honest tool could from these inputs.
- It cannot tell you what mitigation would cost. This platform holds zero quote observations and publishes no price benchmark.
- Nothing here is medical advice. What a given exposure means for a specific person belongs with a physician.
Related
- What does my result mean? — Your number, read against guidance and against the conditions it was measured in.
- Should I test? — Five reasons to test, and which one applies to you.
- Compare two quotes — Review both bids on the eight lines that explain almost every price gap.
- Is mitigation worth it — Clear yes, clear no, and the genuinely marginal middle.
- Radon mitigation ROI — Four returns: transaction, negotiation, usable space, and risk.
- What makes a great system — Six design choices that decide whether a system performs for a decade.
- Radon Mitigation Cost Driver Index — The variables that move a quote, their direction, and their relative magnitude — no invented dollar figures.
- Radon Testing Method Comparison Dataset — Which method answers which question — and which decisions each one cannot carry.
- 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.
- EPA recommends action at 4 pCi/L and recommends considering action between 2 and 4. The distinction between a recommendation and a consideration is EPA’s, not ours.
- Radon exposure is cumulative, so time spent in the space and years of residence both bear on total exposure. That is arithmetic rather than a claim about risk magnitude.
- EPA describes radon and smoking as compounding risks.
- Mitigating before a basement is finished is cheaper than after, because suction placement and routing are unconstrained while the space is open.
- What we do not knowQuestions you may reasonably have that this page does not answer.
- How much risk reduction you personally obtain from mitigating at a given starting concentration. That is a dose-response question we are not equipped to answer for an individual.
- Whether your reading is representative of your annual average, unless you have run a long-term detector.
- What research would settle itWhat it would actually take to answer the above — naming it is the difference between honesty and hedging.
- Individual-level risk estimates at residential concentrations, resolved finely enough to inform a decision in the 2–4 band, remain an active research area rather than a settled one. Pooled residential case-control evidence establishes direction more firmly than magnitude at the low end.
- A cost-effectiveness analysis of mitigation across the consideration band, using real quote data, would turn this judgement call into an arithmetic one. Neither the risk resolution nor the quote data currently exists for that.
- What we do not claimClaims you might expect to find here and will not, with the reason.
- We do not claim a result below 4 pCi/L carries no risk, and we do not claim mitigation eliminates risk.
- We do not claim a specific final reading is achievable. Outcome commitments belong in a contractor’s written scope, not in a tool.
- We do not claim a cost, a payback period, or a return on investment, because all three would require pricing data we do not hold.
- We do not make a health claim about children or pregnancy beyond the arithmetic that more remaining years means more cumulative exposure.
- What we cannot independently verifyFacts this page relies on that we could not confirm ourselves.
- Whether your test was validly conducted, or whether the device and laboratory were in good standing.
Sources
- U.S. EPA — Radon
- U.S. EPA — A Citizen’s Guide to Radon
- U.S. EPA — Health Risk of Radon
- U.S. EPA — Consumer’s Guide to Radon Reduction
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