Short answer
A result of 5 pCi/L is above EPA's 4 pCi/L action level, so plan to fix the home once the number is confirmed, with a followup test if it came from one short-term test. It calls for a planned fix rather than alarm: most homes can be brought to 2 pCi/L or below.
Next step: pick the right test for your home. Which test to use
5
If the 5 came from one
The usual fix is a vent pipe and fan that pulls radon from beneath the house; subslab suction typically lowers radon by 50 to 99 percent, and most homes can be fixed for about the same cost as other common home repairs. Test within 30 days of installation.
What to do next: run the follow-up test if you need one, then get quotes from certified
In a picture · 1 min read
A result of 5
See the 5 pCi/L page for this level in detail.
At a glance · 1 min read
If your 5 came from one
| Your 5 came from | Next step |
|---|---|
| One short-term test | Take a followup test: long-term, or a second short-term |
| The average of two short-term tests | Plan a fix |
| A long-term test | Plan a fix |
In a picture · 1 min read
A 5 is a reason to act, not to panic. The time between exposure and the onset of lung cancer may be many years, and not everyone exposed to elevated radon will develop it. What matters is lowering the level where you spend your time and keeping it low.
EPA estimate, lifetime exposure
| Radon level | Could get lung cancer, per 1,000 | What to do |
|---|---|---|
| 20 pCi/L740 Bq/m³ | Smoked: About 260Never smoked: About 36 | Fix your home |
| 10 pCi/L370 Bq/m³ | Smoked: About 150Never smoked: About 18 | Fix your home |
| 8 pCi/L300 Bq/m³ | Smoked: About 120Never smoked: About 15 | Fix your home |
| 4 pCi/L150 Bq/m³ | Smoked: About 62Never smoked: About 7 | Fix your home |
| 2 pCi/L75 Bq/m³ | Smoked: About 32Never smoked: About 4 | Consider fixing between 2 and 4 pCi/L |
| 1.3 pCi/L50 Bq/m³ | Smoked: About 20Never smoked: About 2 | Average indoor radon level |
| 0.4 pCi/L15 Bq/m³ | Smoked: About 3Never smoked: No figure given | Average outdoor radon level |
Radon can cause lung cancer in both non-smokers and smokers, and a smoker exposed to radon has a much higher risk. Stop smoking and lower your radon level to reduce your lung cancer risk.
In a picture · 1 min read
The method primarily used is a vent pipe and fan that pulls radon from beneath the house and vents it outside. Subslab suction, the most common and usually the most reliable method, typically lowers radon by 50 to 99 percent, and radon levels can be reduced in most homes to 2 pCi/L or below.
Most homes can be fixed for about the same cost as other common home repairs. Get an estimate from one or more qualified radon
At a glance · 1 min read
A confirmed 5 is a project with a clear order. Many states require radon professionals to be licensed, certified or registered, so check credentials when you collect estimates, and keep the follow-up test separate from the installer if you can.
| Step | What to do |
|---|---|
| 1. Confirm | A long-term test, or the average of two short-term tests |
| 2. Estimates | Get an estimate from one or more qualified radon mitigation contractors |
| 3. Install | Usually subslab suction, the most common and usually the most reliable method |
| 4. Test again | Within 30 days of installation |
| 5. Keep it running | The fan must run continuously; retest at least every two years |
In a picture · 1 min read
Test within 30 days of installation to confirm the level came down, keep the fan running continuously, and retest at least every two years. You will reduce your risk of lung cancer when you reduce radon levels, even after living with an elevated level for a long time.
Day of installation
The system goes in
Keep the fan running at all times: it must run continuously for the system to work correctly.
No sooner than 24 hours
Earliest post-mitigation test
Test no sooner than 24 hours after your system is in operation with the fan on, if it has one.
Within 30 days
Post-mitigation test done
A two- to seven-day measurement is recommended, and EPA recommends an independent follow-up radon measurement as well as any test the contractor runs.
At least every two years
Retest
Retest your home at least every two years to be sure radon levels remain low.
Test conditions: Windows and doors must be closed 12 hours before and during the test, except for normal entry and exit. Not drawn to scale.
After a remodel. After you remodel, retest in the lowest lived-in area to make sure the construction did not reduce the effectiveness of the radon reduction system.
Questions · 1 min read
It is above EPA's action level, so a fix is recommended once the result is confirmed. It calls for a planned fix, not alarm.
If it came from one short-term test, yes: take a followup test, long-term or a second short-term, to be sure.
Yes. Radon levels can be reduced in most homes to 2 pCi/L or below, and some systems cut levels by up to 99 percent.
It means a fix to plan for. See should I buy a house with radon.
It is about 1.25 times the action level. The risk rises with the level and the time spent in the home.
Most homes can be fixed for about the same cost as other common home repairs. Get an estimate from one or more qualified contractors.
About 185 Bq/m3, since 1 pCi/L is 37 Bq/m3.
How a radon test works, who can run one, and how to read the number it gives you.
How a professional radon test works, what it proves and whether it is worth it.
Read the guideWhat counts as high and how to bring them down.
Read the guideEPA's action level, WHO's reference level and what counts as acceptable.
Read the guide