What happens next

What happens after mitigation

“The crew has left. There is a pipe and a fan and a gauge, and I do not know what I am supposed to do with any of it.”

A mitigation system that has never been measured after installation is an unverified claim. That sentence is the whole reason this page exists: the industry norm is to treat installation as completion, and it is not.

The sequence below ends with the system becoming boring, which is the correct outcome. Getting there takes one walkthrough, one measurement, and about ten minutes of filing.

Before the crew leaves
The walkthrough, while fixing things is still their problem
Walk the whole installation with whoever ran the job. Look at the discharge point relative to windows and the roofline, the fan location relative to living space, the sealing at the floor-wall joint and any sump, and the gauge. Ask them to show you the reading and tell you what it should look like in six months. Write that reading down.
Whose move
You, in the fifteen minutes before the van leaves. This window does not reopen.
If this does not happen
Anything you notice after the crew has gone becomes a phone call, a scheduling problem, and sometimes a dispute. The same observation made while they are packing up is a five-minute fix.
Where people fall out
Accepting "it is all set" without being shown the gauge. The gauge reading on day one is the baseline against which every future reading is judged, and nobody can reconstruct it later.
24 hours to about 30 days after installation
The confirmation test
A post-installation measurement under closed-building conditions is what establishes that the system reduced the level. Guidance describes this as part of the job rather than as an optional extra. Who runs it matters less than that it happens and that it is documented — though an independent measurement carries more weight in a transaction than one run by the installer.
Whose move
Whoever your contract says. If it does not say, that is a gap to close before the invoice is paid.
If this does not happen
You own a system with no evidence attached. In a future sale this is the difference between "mitigated, verified at 1.8" and "there is a pipe, we assume it works."
Where people fall out
Testing too soon, in the first day, before the system has stabilised — or testing with windows open because the work made the house dusty.
Within a week of the confirmation result
Assemble the file
Four documents make a system an asset rather than a curiosity: the proposal and final scope, the installer credential, the warranty terms with dates, and the post-installation result. Put them together, digitally and on paper. This is the single highest-return ten minutes in the whole sequence, and it is almost always skipped.
Whose move
You. No contractor will assemble this for you, and most will not think to offer.
If this does not happen
At sale, an undocumented system reads to a buyer as evidence of a past problem rather than as a solved one. Reconstructing the file years later ranges from tedious to impossible.
Where people fall out
Keeping only the invoice. An invoice proves you paid; it does not prove the system works or that anyone credentialed installed it.
The first year
Learn what normal sounds and reads like
Glance at the gauge when you pass it. You are building a sense of the normal range so that a change registers as a change. A fan makes a steady low noise; a new rattle, a whine, or silence each mean something different. None of this requires tools or expertise, only a baseline.
Whose move
You, incidentally, a few times over the year.
If this does not happen
A fan that fails silently can go unnoticed for a year or more, and the entire time the house is unmitigated while everyone believes otherwise.
Where people fall out
Assuming a running fan means a working system. A fan can run while the seal has failed or the pipe is blocked, and the gauge is what shows the difference.
Every year, then every two
It becomes routine
An annual ten-minute check and a measurement every couple of years is the whole ongoing burden. Add a measurement after any work that changes airflow — a new HVAC system, a finished basement, foundation work — because those change the conditions the system was designed around.
Whose move
You, on a reminder you set once.
If this does not happen
Without a scheduled measurement, the system status quietly reverts to an assumption, which is where it started before you paid to change it.

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 confirmation test came back above the action level: This is a diagnosable outcome with an order of likely causes, and a properly written contract has already told you whose problem it is. Work it as a diagnosis rather than a dispute.
The system is noisy in a way that bothers you: Noise and vibration have distinct causes, and most are correctable. It is worth raising while the installation is recent.
You bought the house with the system already in it: You have no baseline and no file. Establish both: a measurement now becomes your baseline, and the system becomes documented from your ownership forward.
The fan fails within the warranty period: The warranty terms and the fan age determine whether this is a repair, a covered replacement, or an out-of-pocket one.

After a radon test — Two weeks of waiting, then one decision that determines everything after it.
After replacing a fan — A new fan resets the baseline. Write the new number down.
Is my system working? — The safe checks, in order, and where they stop.
Should I retest? — Time since the last test, plus what has changed in the house — the two things that decide it.
Repair or replace the fan? — Four different problems present the same way. This separates them.
After installation — Confirm it works, then file the paperwork that proves it.
Annual inspection — Ten minutes a year, plus a test every two.
Post-mitigation testing — The measurement that records the level once the system is running — and what to do if it is not what you hoped.
What to expect after installation — Verification, noise, energy, maintenance, and retest intervals.
Retest failed — An elevated verification result is unfinished scope, not a lost cause — and who pays depends on what the contract promised.
How long systems last — The pipe is effectively permanent. The fan is the wear item.
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.: Published mitigation guidance describes post-installation measurement as part of the mitigation process rather than as an optional step.
Mitigation fans are continuously running mechanical components with finite service life, so eventual replacement is expected rather than a defect.
A pressure gauge indicates that the system is developing suction; it does not by itself establish the indoor concentration.
What we do not knowQuestions you may reasonably have that this page does not answer.: What your house will read after mitigation, which depends on diagnostics performed at the suction point and on the building.
How long your specific fan will last, which varies by model and installation conditions.
What research would settle itWhat it would actually take to answer the above — naming it is the difference between honesty and hedging.: Before-and-after measurement pairs with documented diagnostics, which would let anyone describe expected reduction by design.
Field failure data across fan models and ages, which would turn a general service life into a distribution.
What we do not claimClaims you might expect to find here and will not, with the reason.: We do not claim a reduction percentage any system will achieve, because that depends on a house we have not seen.
We do not claim a service life for any named fan model, because we hold no field failure observations.
We do not recommend any contractor, fan, or maintenance plan.
What we cannot independently verifyFacts this page relies on that we could not confirm ourselves.: Whether diagnostics were performed on your installation, which only the contractor documentation and your own observation establish.
Manufacturer service-life claims, which we have not tested and do not restate as facts.

The mitigation lifecycle, from diagnosis to re-verification

What it shows. That installation is one day in the middle of the process rather than the end of it.

Installation is one day in the middle. The phases after it are what turn a pipe into a documented, verified system — and they are the ones most often skipped.

Authored as SVG in this repository, with real text nodes and a long description for screen readers. Reusable under CC BY 4.0 — see the diagram library.

Sources

U.S. EPA — Consumer’s Guide to Radon Reduction
U.S. EPA — A Citizen’s Guide to Radon

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What happens after mitigation

The walkthrough, while fixing things is still their problem

The confirmation test

Assemble the file

Learn what normal sounds and reads like

It becomes routine

When it goes differently

Related

Confidence and limits of this page

The mitigation lifecycle, from diagnosis to re-verification

Sources

Get quotes from credentialed local contractors