Everything you need to know about radon

Answers to common questions, what your number means, and trusted guides from health agencies.

The basics

What is radon?

A radioactive gas from the natural breakdown of uranium in soil and rock, found in the ground everywhere, Vermont included.

Why exposure matters

Radon is invisible and odorless, so it builds up without notice. Long-term exposure is a leading cause of lung cancer among non-smokers.

How it gets inside

Through cracks in concrete, gaps around pipes, sump pits and crawlspaces. Warm air rising in a house pulls soil gas in from below.

Why levels vary

Soil, weather, foundation type and air pressure all play a part. Even neighboring homes can produce very different readings.

Radon by the numbers

Cause of lung cancer among non-smokers

Source: epa.gov

1 in 7

Vermont homes have elevated radon levels

Source: healthvermont.gov

21,000

Radon-related lung cancer deaths a year in the U.S.

Source: epa.gov

What your number means

U.S. results are in picocuries per liter (pCi/L). Most other countries use becquerels per cubic meter (Bq/m³). 1 pCi/L = 37 Bq/m³.

Reading (pCi/L)EPA (U.S.)WHORecommendation

Under 2.0under 74 Bq/m³ Below the EPA range for action Below WHO reference level Lower is still better. Mitigation can reduce it further. Retest every two years.

2.0 – 2.674 – 99 Bq/m³ EPA: consider fixing (2.0–3.9) Just under WHO reference level Mitigation recommended. Retest to confirm if the first test was short-term.

2.7 – 3.9100 – 147 Bq/m³ EPA: consider fixing (2.0–3.9) Above WHO reference level Mitigation recommended. Wingreen can walk you through the options.

4.0 and up148 Bq/m³ and up EPA action level: fix the home Above WHO reference level Mitigation strongly recommended. Most systems are installed in a day.

There is no known safe level of radon. The World Health Organization recommends a reference level of 100 Bq/m³ (about 2.7 pCi/L), and no higher than 300 Bq/m³ where that cannot be reached. Sources: epa.gov, who.int.

Common questions

Have another question? Call (802) 300-0511.

My neighbor tested low. Do I still need to test?

Yes. Radon levels depend on the soil and construction under each house, so neighbors can read very differently. The only way to know your level is to test your home.

Does a new home or a home without a basement have radon?

It can. Radon enters through any contact with the ground, including slabs and crawlspaces, in new and old homes alike.

How long does a test take?

A short-term test runs at least 48 hours under closed-house conditions. Your report is usually ready 3–5 business days after the monitor is picked up.

What does closed-house mean?

ANSI/AARST radon testing standards call for closed-house conditions. For a short-term test they begin 12 hours before the test starts and stay in place until the monitor is picked up:

Windows closed on every level of the home, including rooms not being tested.
Outside doors closed, except for normal coming and going.
Heating or cooling running at normal settings, between 65 and 80 °F.
Systems that bring in outdoor air set to their lowest seasonal setting, and whole-house fans off.
Fireplaces unused, unless one is the main source of heat.
Clothes dryers, range hoods and bathroom fans used sparingly.

Can I move the monitor during a test?

Please leave it exactly where it was placed and keep closed-house conditions until Wingreen picks it up. Moving the monitor will likely invalidate the test, and it may need to be run again.

My level is under 4.0. Should I still mitigate?

Yes, mitigation is recommended. There is no known safe level of radon, the WHO reference level is 2.7 pCi/L, and any reduction lowers your risk.

How often should I retest after mitigation?

At least every two years, and again after renovations, a new heating system or changes to the foundation. A test after installation also confirms a new system is doing its job.

How does a system look and sound?

Quiet and tidy. Each system is placed with your home's appearance in mind, and most installs take one day.

Can I see my results online?

Yes. Reports, invoices and documents are in your portal. Your report is released once the results are returned from the lab, the report is formed, and the invoice is paid.

Trusted guides

Vermont Dept. of HealthRadon in Vermont homesOpen guide Vermont Dept. of HealthRadon data and trackingOpen guide EPAA Citizen's Guide to Radon (PDF)Open guide EPABuying a New Home: Protecting Your Family from Radon (PDF)Open guide WHORadon and healthOpen guide CDCRadon and your healthOpen guide

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