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]

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?

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

A radon report is most useful when you read the number together with the test duration, location, and conditions. This guide explains indoor-air results for U.S. homes. It does not turn a home measurement into a medical diagnosis or replace the measurement professional’s interpretation.

What does pCi/L mean?

Picocuries per liter, written pCi/L, describe radioactive activity in a volume of air. Some devices instead display becquerels per cubic meter, written Bq/m³. These are two units for concentration, not different kinds of radon. EPA commonly presents 4 pCi/L as approximately 150 Bq/m³. [3]

Check the units before comparing devices or reading a threshold chart. A display of 148 Bq/m³ is about 4 pCi/L, not 148 pCi/L. The conversion is 1 pCi/L = 37 Bq/m³; regulatory guidance often rounds the equivalent action level. [4]

How should you interpret the result?

The thresholds above summarize EPA guidance. [1] A report of 3.9 pCi/L should not be treated as categorically harmless while 4.0 is treated as a completely different situation. The goal is to reduce exposure, not to win a pass/fail label.

What if your first short-term test is high?

EPA’s homeowner guidance uses a follow-up measurement to support the mitigation decision. A long-term result at or above 4 pCi/L, or an average of two appropriate short-term tests at or above that level, supports fixing the home. A much higher initial result calls for prompt follow-up rather than waiting months. [2]

Ask the tester three specific questions: Was this an initial screen or a completed decision protocol? Is the reported number the relevant average? What follow-up is appropriate for this result and deadline? A real-estate measurement may follow a protocol that differs from a casual home screening, so avoid adding arbitrary consumer readings to a professional report.

Do not average unrelated rooms, mismatched units, or a single hourly reading with a multi-day result. First confirm that the measurements belong in the same decision process. Save the original reports so a qualified tester can review them.

Why do radon readings change?

Radon levels can vary with time and season. A short test captures a limited period, while a longer measurement better represents a longer stretch of occupancy. [5] A monitor’s current, daily, and long-term averages can therefore differ without being contradictory.

When comparing results, write down the room and floor, dates, duration, units, device, and whether the radon system was operating. This small record helps distinguish a change in the home from a change in how the measurement was taken.

Does a high result mean you are already ill?

No home radon test diagnoses disease or measures an individual’s past dose. Radon is a long-term lung cancer risk; smoking increases the combined risk. Discuss personal health concerns with a clinician while addressing the building’s exposure source. [6]

What happens after the decision to mitigate?

Arrange a qualified assessment, get a written scope, and plan verification testing. Our guide to how radon mitigation works explains the basic system. You can also review Radon Eraser’s mitigation service or ongoing monitoring options.

If you later start using a basement as living space or alter the home, reassess the testing plan. EPA specifically identifies changed lower-level occupancy and renovations as reasons to revisit previous measurements. [7]

Radon result FAQs

A useful radon report starts before the measuring device arrives. Preparation helps the measurement reflect the conditions the test was designed to assess. This checklist is for homeowners planning an indoor-air radon test, including people preparing to buy or sell a home.

Radon is an invisible, odorless radioactive gas. It can accumulate in buildings, and long-term exposure increases lung cancer risk. Smell, a normal home inspection, and the age of a house cannot tell you its radon concentration. [2] If you are new to the subject, start with our explanation of radon and how it enters a home.

Which radon test should you choose?

Short-term tests measure for 2–90 days; long-term tests run for more than 90 days. A longer test generally gives a better picture of exposure across changing conditions. For a home purchase or sale, use a qualified tester and confirm the transaction’s requirements before scheduling. [3]

Share your deadline when booking, rather than assuming a “48-hour test” means the final report will arrive exactly two days later. Device setup, retrieval, laboratory processing, and report delivery are separate parts of the appointment.

What should you do before a radon test?

1. Get the instructions in writing. Ask about the start and finish time, required house conditions, device location, and who to contact if something changes.
2. Tell everyone who uses the home. Include household members, tenants, agents, cleaners, and contractors. Put the testing dates on a shared calendar.
3. Prepare for closed-house conditions. For a 2–4 day test, EPA’s checklist calls for at least 12 hours beforehand and the full test period. Normal brief entry and exit are allowed. [1]
4. Keep access clear. Give the tester room to select a suitable location and leave the device there. Keep children and pets from handling it.
5. Describe the home honestly. Mention a basement, crawlspace, addition, recent renovation, existing radon system, or planned lower-level bedroom or office.

For example, if a test begins at 9 a.m. Tuesday and requires a 12-hour preparation period, closed-house conditions need to begin by 9 p.m. Monday. That is a scheduling example; your actual test must follow its own instructions.

Where should the device go?

Placement depends on the test’s purpose and the applicable protocol. A room used regularly on the lowest appropriate level is generally relevant; kitchens, bathrooms, drafts, heat, and humidity can make locations unsuitable. Let the professional choose the location, or follow your kit’s specific placement directions. Do not move the device to a more convenient shelf after setup. [4]

What can you do during the test?

You can usually continue normal household activities while respecting the test conditions. Operate heating and cooling normally as directed; avoid deliberately bringing extra outdoor air into the home. Leave an existing active radon system operating. EPA’s testing checklist explains these conditions in more detail. [1]

If a window is left open, a device is knocked over, or an unexpected event occurs, record what happened and tell the tester. Do not conceal the event or try to compensate by changing conditions later. The tester can determine whether the measurement remains usable or needs repeating.

What happens when testing finishes?

For a kit, record the required information and return it promptly according to the laboratory instructions. Keep the complete report, including the test dates, location, method, and reported average. [4] Read our guide to interpreting radon test results before deciding what the number means for your home.

Make a simple home record: report, device instructions, notes about unusual conditions, and any follow-up appointment. This makes future comparisons much more useful than an isolated number saved in a text message.

Radon test preparation FAQs