If a test shows elevated radon, it helps to understand what the proposed equipment actually does. This guide explains the typical soil-gas reduction approach and the questions a homeowner should ask before accepting a system proposal. It is an overview, not a do-it-yourself installation specification.
How does a radon system reduce indoor levels?
Radon can move from the ground through openings in the foundation. Soil suction creates a collection route beneath the building and carries the gas outside, where it disperses. EPA generally favors methods that reduce entry into the home. [1]
Soil gas beneath the slab or membrane
A fan draws gas through sealed piping
Gas exits outdoors above the home
This common approach is called active soil depressurization. The word “active” refers to the powered fan. It does not mean the system measures radon continuously: moving soil gas and measuring indoor concentration are different jobs.
Why does the foundation change the design?
| Foundation | Typical approach to discuss |
|---|---|
| Basement or slab | Subslab suction draws soil gas from below concrete. |
| Exposed-earth crawlspace | A sealed membrane over the soil can provide a collection area for suction beneath it. |
| Mixed foundations or additions | The assessment needs to account for the different areas; one collection point may not address them all. |
These are common concepts from EPA’s reduction guide, not a design for a specific house. [2] Tell the contractor about additions, inaccessible crawlspaces, finished rooms, sumps, and any previous system. A photograph or sketch can help the initial discussion, but it cannot substitute for the required assessment.
Is sealing cracks enough?
Sealing can support a radon reduction system, but EPA does not recommend relying on sealing alone. [2] Ask the contractor to explain what each proposed seal contributes and how the completed system will be tested. A neat-looking floor repair is not evidence that indoor radon has been reduced.
What should the proposal and handover include?
A useful proposal makes the work understandable before installation. Ask for a written explanation of the selected method, pipe route, fan location, electrical work, discharge location, visible equipment, verification plan, and any warranty terms. Confirm who handles permits or other local requirements where applicable.
- Design: Which foundation areas will the system address, and why?
- Appearance: Where will visible piping and equipment sit?
- Verification: Who performs the follow-up test, and who receives the report?
- Handover: How do you read the operating indicator and recognize a problem?
- Service: Who should you contact if the fan stops or a warning appears?
Keep the scope, installation details, test report, and operating instructions in one place. If you sell the home later, those records explain the equipment much better than a photograph of the pipe alone.
When should you test after mitigation?
EPA’s consumer guide recommends testing within 30 days after installation, after the system has operated for at least 24 hours. It also recommends independent follow-up measurement to avoid a conflict of interest. Follow the applicable testing protocol and the qualified tester’s instructions. [2]
Before the installer leaves, put the verification date on the calendar. Installation is an action; the follow-up result is evidence of its effectiveness in that home.
Does the pressure gauge tell you the radon level?
No. A U-tube manometer indicates pressure difference associated with system operation. It is not a radon detector. A normal-looking indicator does not replace a radon test. [3] Have the installer show you the normal operating indication and the response to an abnormal reading.
For long-term care, check the warning indicator as instructed and keep the system operating. EPA advises retesting at least every two years after mitigation. [1] Also revisit testing after substantial changes to the home or use of its lower levels. [4]
What determines the cost?
A useful quote relates the price to your home: foundation arrangement, access, routing, equipment, electrical needs, and the verification scope. Compare what is included rather than comparing a single advertised price with a complete proposal. Ask how unexpected conditions would be handled and documented before additional work begins.
See Radon Eraser’s mitigation service for the service process, and our monitoring information for the distinction between a system indicator and a radon measurement.
Radon mitigation FAQs
Can opening windows replace a mitigation system?
Ventilation can change indoor radon temporarily, but it is not a dependable year-round substitute for a properly selected reduction method. CDC describes increased airflow as temporary and recommends professional reduction when indicated. [5]
Can I switch the fan off when I am away?
An active system is designed for ongoing operation. Follow its operating instructions rather than treating the fan as an occasional appliance. Contact the installer if noise, electricity use, or a warning makes you consider switching it off.
Will mitigation remove every trace of radon?
The goal is lower indoor exposure, not a claim of zero radon. The actual result must be measured. There is no known safe radon level, so a successful installation should be evaluated with test results rather than an “all clear” label. [6]
Does a new house need testing?
Yes. New construction and radon-resistant features do not prove a low indoor concentration. Test the home and use the result to decide whether further action is needed. [7]
Start with the measurement
If you do not yet have a report, read our testing preparation checklist. If you do, use our results guide and request a property-specific quote. Our locations hub covers service areas across Tennessee, Georgia, and Alabama.
Sources and further reading
- EPA: Checking a mitigation system.
- EPA: Consumer’s Guide to Radon Reduction.
- Michigan EGLE: Test for radon — pressure indicators versus radon measurement.
- EPA: When to retest.
- CDC: Reducing radon levels.
- EPA: Radon action level.
- EPA: A Citizen’s Guide to Radon.