Radon Connect
What happens next

What happens after you buy a home

“We closed. Radon either came up during the sale or it did not, and I want to know where I actually stand.”

A new owner has one advantage no seller and no buyer under contract has: complete control of the building and no deadline. Closed-building conditions are trivial to maintain in a house you have just moved into and nobody is showing.

That makes the first month the best measurement opportunity you will get for years. The sequence below assumes you want a real number rather than a reassuring one.

  1. The first week

    Find out what the file already contains

    Go through the closing documents for anything radon-related: a disclosure, a test result, a mitigation invoice, a warranty. What you find changes what you do next. A documented system with a post-installation result means you are verifying, not investigating. Nothing at all means you are starting from zero, which is the most common case.

    Whose move
    You, with the closing packet. Your agent can often retrieve what is missing while the transaction is recent.
    If this does not happen
    Documents get harder to obtain the further you are from closing. A seller who would have forwarded a warranty in week one may be unreachable in month six.
    Where people fall out
    Assuming no disclosure means no radon. Disclosure obligations concern what a seller knew, and most sellers never tested.

  2. The first month

    Test the house under your own conditions

    This is the measurement worth having. If the house is empty or lightly occupied, closed-building conditions are easy to hold for the full duration. Place the device on the lowest level you live in or reasonably could, and record the placement so a future retest is comparable. If radon was tested during the transaction, this still matters: that test ran under someone else conditions, often with the house being shown.

    Whose move
    You, as soon as you have the keys and before life gets busy.
    If this does not happen
    The window closes as the house fills with routine. In an occupied family home, maintaining closed conditions for four days is a genuine imposition rather than a formality.
    Where people fall out
    Relying on the transaction test. It answered a contractual question under contested conditions, which is not the same as characterising your house.

  3. Within a month of the result

    If you inherited a system, establish a baseline for it

    A system you did not install has no baseline you can trust. Record the gauge reading now and treat it as your day one. Photograph the installation — discharge point, fan location, sealing — so a later change is visible. Then find out what it is: manufacturer and model from the fan label, and the installer name if it is on a sticker.

    Whose move
    You, once, with a phone camera.
    If this does not happen
    Without a baseline you cannot tell a gauge change from a gauge you have always misread, and the first indication of failure becomes a measurement rather than a glance.
    Where people fall out
    Assuming an inherited system works because it is running. It may never have been verified, and the previous owner may not know either.

  4. Months 2 to 12

    Fold it into the ownership routine

    Whatever you found, it becomes a line in the house file alongside the furnace and the roof. If you mitigated, the post-installation sequence takes over. If you tested clear, note the date and the cadence for the next one. If you deferred a decision, put a date on it rather than leaving it open.

    Whose move
    You, when you set up the rest of the house records.
    If this does not happen
    An open decision with no date attached becomes a decision made by default, and the default is doing nothing indefinitely.

  5. Year 2 and beyond

    Retest after anything that changes airflow

    Finishing a basement, replacing HVAC, adding a bathroom fan, sealing or opening a crawl space, or foundation work all change the pressure relationship between the house and the soil. Each is a reason to measure again regardless of what the last result said.

    Whose move
    You, prompted by the renovation rather than by the calendar.
    If this does not happen
    A renovation can move a house from clear to elevated without anyone noticing, because nothing about the house feels different.

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.

Radon was tested during the transaction and came back clear
Retest anyway under your own conditions. The transaction test answered a contractual question, often with the house being shown, and it may not describe how you will live in it.
You inherited an undocumented mitigation system
Measure to find out whether it works, then document it from your ownership forward. An unverified system is an assumption you have taken on.
The seller disclosed a known elevated result and you bought anyway
You already have the number. The question is design and scheduling, not investigation.
The house is new construction with a passive pipe
A passive stack reduces risk without establishing a result. Measure, and if it is elevated, activation is usually a smaller job than a new installation.

Related

  • After a radon test — Two weeks of waiting, then one decision that determines everything after it.
  • 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.
  • Should I test? — Five reasons to test, and which one applies to you.
  • What does my result mean? — Your number, read against guidance and against the conditions it was measured in.
  • Is my system working? — The safe checks, in order, and where they stop.
  • Buying — Order early, verify the existing system, get it in the amendment.
  • Before testing — Get the conditions right, or the number means nothing.
  • Annual inspection — Ten minutes a year, plus a test every two.
  • Buying a home with high radon — What to require, what to negotiate, and why this is a solvable finding.
  • When to retest — Every two years, plus after anything that changes how the house meets the soil or how it moves air.
  • Activating a passive system — Activation is an engineering evaluation of a rough-in you did not watch being built — not simply a fan purchase.
  • 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.
  • 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.
  • Closed-building conditions and placement are specified in testing guidance, and a newly purchased house is unusually easy to hold them in.
  • Changes that alter airflow or building pressure are grounds for retesting under published guidance.
  • Disclosure obligations, where they exist, concern what a seller knew rather than what could have been discovered.
What we do not knowQuestions you may reasonably have that this page does not answer.
  • Whether an inherited system was installed to standard, since the diagnostics that would show it happened before you owned the house.
  • What the house reads under your occupancy, which is the whole reason to measure rather than infer.
What research would settle itWhat it would actually take to answer the above — naming it is the difference between honesty and hedging.
  • Paired transaction-period and post-closing measurements in the same houses, which would quantify how often a transaction test misrepresents a house.
  • Before-and-after measurements around common renovations, which would rank which changes actually matter.
What we do not claimClaims you might expect to find here and will not, with the reason.
  • We do not claim what a house will read, before or after purchase.
  • We do not give legal advice about what a seller was obliged to disclose in your state.
  • We do not claim any renovation raises or lowers radon by a stated amount, because we hold no paired measurements.
What we cannot independently verifyFacts this page relies on that we could not confirm ourselves.
  • What the previous owner knew, tested, or was told.
  • Whether an inherited warranty is still valid, which depends on terms and on transferability we cannot read from here.

Sources

  1. U.S. EPA — Home Buyer’s and Seller’s Guide to Radon
  2. U.S. EPA — A Citizen’s Guide to Radon

Get quotes from credentialed local contractors

Free to request and no obligation. We verify credentials with the issuing authority before any request routes to a contractor.

Start a request