How to test for radon gas?


A radon test can be performed during the inspection window for a real estate transaction, or by any homeowner who wants to know the radon concentrations within their home. The EPA recommends you know the indoor radon level in any home you consider buying.

Real estate transaction radon testing is short-term, using a continuous radon monitor, with duration of at least 48 hours.

Any home can have elevated radon levels, and even homes next to each other can have different levels of indoor radon due to construction and geographic difference. Every home should be tested, old or new, and even if it already has a radon remediation system in place.

The radon tester must enter a house twice for each test. Since our radon monitors are in continuous use, it is advisable to plan ahead and call early to schedule the radon test during the planned inspection window.

A continuous radon monitor records data once per hour for the test duration, and the results are averaged. For real estate transactions, the radon monitor is placed in the lowest level of the house suitable for occupancy. If the lowest level of your house is greater than 2,000 square feet, two radon monitors will be required for the test.

What you should do during the radon test

Before starting the radon test, the house must be fully closed for at least 12 hours and remain closed for the entire 48 hour test, except for normal entry and exit.

The radon monitor is about the size of shoebox and needs to be placed where it won’t be disturbed during the testing time period.

If closed house conditions are not maintained, or if the radon monitor is disturbed, the test will be invalidated.

Once the test is complete, we will pick up the testing machine, and email you a detailed report that includes the radon concentration for each hour, and the average during the entire test.

Above is an example radon test result for a home that had average radon concentration of 14. pCi/L. The radon test machine records the concentration each hour for the test duration and averages the results with minimum and maximum concentrations. The EPA action level is 4.0 pCi/L, so the Test Result is “Mitigation Recommended” as it is over the set action level.

Radon Done radon testing in progress door hanger. Closed house conditions must be maintained during the 48-hour test, with all doors and windows closed.

Radon Done radon testing in progress door hanger. Closed house conditions must be maintained during the 48-hour test, with all doors and windows closed.


Any home can have high radon, the only way to know is to test.

Include a radon test with your home inspection for any house you consider buying.

Schedule a Radon Test Now for $150 What is Radon Gas?

Radon Information

Skyline of Columbus, Ohio at night. Columbus is the capital of Ohio, located in central Franklin County.

What are radon levels in Franklin county, Ohio?

Central Ohio has high radon potential according to the EPA. Average radon levels recorded and submitted to the Ohio Department of Health range from 2 to 4 Pci/L (picoCuries per liter), shown in light blue in the graphic below, to ZIP Codes with averages over 10 Pci/L, shown in red in below.

Although there is no safe level of radon exposure, the EPA Action Level for indoor radon is 4.0 Pci/L. The first step to understanding the radon level inside your own home is to test–this is something you can include with your home inspections when buying a home, or anytime for your current home. Even if you already have a radon mitigation system, the EPA recommends that you test your home every two years–many changes to your home can change the amount of radon trapped inside the living area, including new windows, siding, or roof.

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Uranium emitting alpha particles in a cloud chamber

What is radon gas?

Radon is an odorless, colorless, tasteless, radioactive gas. Radon comes from the decay of radioactive uranium that can be found in small amounts in rocks and soil throughout nature. In areas with disturbed earth, and loose fill, like when a home is built, radon escapes from the soil.

Radon gas exposure is the number one cause of cancer for non-smokers, even greater than second-hand smoke. Most people are exposed to radon gas inside their own homes, and this is their greatest exposure to natural ionizing radiation.

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All radon inspectors who enter your home wear face coverings and use hand sanitizer.

COVID-19 safety for our company and your family

Radon Done is committed to the safety of your family and our own employees. During this pandemic, it is critical that we all observe safety protocols that minimize the risk of disease transmission.

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Radon Done radon test in progress door hanger. Homes undergoing radon testing must have all windows and doors closed for the duration of the test

Radon gas in Ohio

Central Ohio has relatively high natural concentrations of uranium from glacial deposits and shale, which during radioactive decay, produces radium and radon.

The EPA’s current radon action level is four picocuries of radon per liter of air (4 pCi/L). Most counties in central Ohio have high potential for radon, with predicted average indoor greater than the EPA action level. According to one study cited by Ohio Department of Natural Resources Department of Geological Survey, 38% of Ohio’s 88 counties had average indoor radon levels above 4.0 pCi/L, but Licking County’s average was above 8.0 pCi/L. Seven Ohio counties—Carroll, Fairfield, Franklin, Harrison, Knox, Pickaway, and Ross—had average indoor Radon concentrations between 6 and 8 pCi/L.

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