Radon Connect
What happens next

What happens after a radon test

“The test is done, or the device is in the post, and nobody has told me what happens now.”

The gap between finishing a test and knowing what to do is where most homeowners get stuck, usually because the report arrives as a single number with no instructions attached.

The sequence below is the same whether your number was high or low. The fork comes at stage three, and which branch you take depends more on how the test was run than on what it said.

  1. Immediately

    The device stops, and the conditions stop mattering

    Once collection ends you can open windows again. If you used a laboratory kit, the clock that matters now is the postmark: most kits specify a maximum delay between end of collection and arrival at the laboratory, and exceeding it invalidates the sample. A continuous monitor has no postal step, which is one of the reasons it holds up better under challenge.

    Whose move
    You, that same day, if a kit has to be posted.
    If this does not happen
    A kit left on a counter for a week is a wasted test and a wasted fee. If you have missed the stated window, ring the laboratory before posting it — many will decline to process a kit outside their window, and knowing that now is cheaper than learning it from a rejection letter. Whether a returned result should be relied on is their call rather than ours.
    Where people fall out
    Treating the posting deadline as advisory. It is the single most common reason a paid-for kit produces a number nobody can defend.

  2. 3 to 14 days

    The laboratory reports a number

    Turnaround depends on the laboratory and on how the sample travelled. What comes back is a concentration, a collection period, and — from a good laboratory — the conditions the device recorded. Read the conditions before the number. A result collected over 48 hours in a house that was being shown to buyers is a different piece of evidence from the same number collected over 48 closed hours.

    Whose move
    The laboratory. You are waiting, and there is nothing to accelerate.
    If this does not happen
    If the stated turnaround has passed by more than a few days, contact the laboratory with the kit identifier before assuming the sample was lost. Kits do go astray in the post, and most laboratories will confirm receipt.
    Where people fall out
    Reading the concentration and never opening the conditions section, which is where the answer to "can I rely on this" actually lives.

  3. The same day the result arrives

    Decide whether the result is trustworthy before deciding what it means

    This is the fork. A valid result — closed conditions maintained, sensible placement, adequate duration, no severe weather — supports a decision. A result with a condition problem supports only one thing, which is another test. Working out which you have takes about ten minutes and saves people from mitigating on the strength of a number that would not have survived a question from a buyer.

    Whose move
    You. Nobody else will raise the validity question, and a contractor has no reason to.
    If this does not happen
    Skipping this step does not make the problem go away; it defers it to the worst possible moment, which is usually mid-transaction when the other side asks how the test was run.
    Where people fall out
    Going straight from a number to a contractor call. If the test was compromised, every dollar spent after this point was spent on a guess.

  4. Within a week of a valid result

    Either retest, or start gathering proposals

    On a valid result above the action level, the next step is proposals from credentialed contractors — plural, because a single quote gives you nothing to compare it against. On a valid result in the consideration range, a longer-duration test is often the better spend, because it tells you where your annual average sits rather than where one weekend sat. On a compromised result, retest under controlled conditions.

    Whose move
    You, on your own timetable, unless a contract deadline is imposing one.
    If this does not happen
    Nothing forces this step, which is exactly why it stalls. Results sit in drawers for years. If you are going to defer, put a date on it rather than leaving it open.
    Where people fall out
    Requesting one proposal and treating it as the market price. Two proposals for the same house routinely differ in scope rather than in number.

  5. 2 to 12 months later

    The result becomes part of the house record

    Keep the report. A dated result with documented conditions is worth real money at sale — it is the difference between disclosing a known figure and having a buyer discover an unknown one under a contract clock. If you did nothing else, this stage still applies.

    Whose move
    You, once, into whatever file holds the roof warranty.
    If this does not happen
    A lost report means the next owner or the next transaction starts from zero, and the test you already paid for buys nothing.

When it goes differently

A sequence with only one ending is a script rather than a description. These are the divergences worth knowing about before you are in one.

The result came back below the action level and the test was valid
Nothing is required. Record the result, and retest on the standing cadence or after any change that alters airflow in the house.
The result sat in the consideration range between the two thresholds
A longer-duration test is usually the better next spend than a mitigation proposal, because a short measurement in that range does not tell you where your annual average is.
The test was run during a storm, or with a window open, or in a bathroom
The number is not evidence. Retest under closed-building conditions before making any decision or telling anyone the figure.
There is a contract deadline attached to this result
The sequence compresses and the transaction pages take over. Start from the timeline rather than from the number.

Related

  • After mitigation — Installation is not the end of the job. Verification is.
  • After a failed inspection — A contract clock is running. The order of operations changes because of it.
  • What does my result mean? — Your number, read against guidance and against the conditions it was measured in.
  • Should I retest? — Time since the last test, plus what has changed in the house — the two things that decide it.
  • 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.
  • Before testing — Get the conditions right, or the number means nothing.
  • During testing — Four days of not doing things. That is genuinely the whole job.
  • False positives — Most disputed results are not false — they are invalid, mismeasured, or comparing two different things.
  • When to retest — Every two years, plus after anything that changes how the house meets the soil or how it moves air.
  • Weather effects — Weather genuinely moves indoor radon — but it explains variation around a number, not a number well above the action level.
  • How testing works — Devices, placement, closed-building conditions, and what invalidates a result.
  • All six sequences — every moment we have mapped.

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 sequence 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.
  • Laboratory kits specify a maximum interval between end of collection and receipt, and exceeding it compromises the sample.
  • Published guidance treats a short-duration measurement as a screening step and recommends follow-up before acting in the range below the action level.
  • Result validity depends on conditions and placement, both of which are specified in testing guidance rather than left to preference.
What we do not knowQuestions you may reasonably have that this page does not answer.
  • How long your specific laboratory will take, which varies with volume and season and is not something we can state for any provider.
  • Whether your particular result sits above or below your house annual average, which a single short measurement cannot establish.
What research would settle itWhat it would actually take to answer the above — naming it is the difference between honesty and hedging.
  • Turnaround observations across laboratories, which would replace the range quoted here with a distribution. We hold none.
  • Paired short and long measurements in the same houses, which is the evidence that would quantify how often a screening result changes the decision.
What we do not claimClaims you might expect to find here and will not, with the reason.
  • We do not claim a turnaround time for any named laboratory, because we have collected no observations from any of them.
  • We do not tell you what to do at a specific concentration, because that depends on occupancy and validity, and the tools publish their reasoning instead.
What we cannot independently verifyFacts this page relies on that we could not confirm ourselves.
  • Whether your kit arrived within its stated window, which only the laboratory record shows.
  • The current content of the cited guidance documents, for the network reason stated in our methodology.

Sources

  1. U.S. EPA — A Citizen’s Guide to Radon
  2. U.S. EPA — Radon

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