Radon Testing During Home Inspections (Is It Necessary?)

Do you want to learn about the radon testing during a home inspection?

Radon testing takes at minimum 48-hours to determine if there are elevated levels of radon gas in the home. You may want to read my guides on mold home inspections and asbestos home inspections which are also air quality hazards.

In this guide, I will go over…

  • Radon testing requirements during home inspections
  • Health risks of elevated radon gas
  • The causes of radon gas in homes
  • How radon testing is performed during home inspections
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Is Radon Testing Necessary?

Radon testing isn’t necessary during a home inspection, but it is recommended by the EPA. The home may already have a radon mitigation system installed, or the seller may provide proof that radon has been tested — in which case you may opt out of radon testing.

If you have any doubts, you should get a radon test with your home inspection — it is cheap and effective way to be aware of a well-known health risk.

Home inspectors will leave a testing device in the home for 2-4 days which will monitor the radon levels in the home.

The device will either be a radon test kit that is sent to a lab, or it can be an electronic meter that will give instant results.

Read Also: 7 Things That Fail A Home Inspection

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Radon mitigation system

Sample Radon Test Result

Below is a picture of a real radon test kit result from one of my home inspections in 2019. This home has a radon level of 9.5 pCi/L (picocuries per liter) which is more than twice the minimum ‘action level’ recommended by the EPA.

Any time a home is higher than 4 pCi/L, it is recommended to perform a follow up test for confirmation. If confirmed, radon mitigation measures is advisable.

radon testing home inspection
Actual test result of elevated radon during home inspection

Risk Factors of High Radon Levels

The main health risk of having high radon in your home is lung cancer. Radon gas is radioactive, and these molecules can get trapped in your lungs over time — damaging your lung tissue.

According to the EPA, radon is the number one cause of lung cancer among non-smokers. The EPA also states that about 21,000 cases of lung cancer every year are the result of radon gas.

And if you are a smoker and live in a home with 20 pCi/L level of radon gas — your risks of getting cancer is 250x more than your risk for drowning. Of course, negative health effects don’t happen overnight, and it can take years before any symptoms appear.

Read Also: What Fixes Are Mandatory After A Home Inspection?

How Radon Testing Is Done During Home Inspections?

There are two main testing types for radon: long term and short term.

Short term testing is what home inspectors usually do during inspections, and we leave the testing equipment in the home for 2-4 days.

Long term testing can take 90 days or longer and is more accurate than short term testing. Of course, for a real estate transaction, the long term test is hardly ever performed since it takes too long.

Read Also: The Top 16 Questions To Ask During A Home Inspection

How Does Short Term Radon Testing Work?

There are also two main types of short term tests: charcoal packets and continuous radon monitors.

Below is a picture of an charcoal radon test kit that was used during a home inspection.

radon testing home inspection
Charcoal radon test packet

Charcoal Radon Tests

Charcoal radon tests are packets filled with activated charcoal that captures the radon test gas over 2-4 days.

Homeowners can also buy DIY charcoal test packets at hardware stores or online — but these won’t count as official tests for the home inspection.

Home inspectors place two of these charcoal packets in the lowest livable area of the home for 2-4 days. When we place these tests, we try to place them away from windows, doors, and air vents. The home inspector then picks up the radon tests, and ships it off to a lab.

The upside of the charcoal radon test is that it is sent to a laboratory for professional measurement. It is highly unlikely that the lab will screw up the test result.

The downside is that depending on the shipping, it can take 1-7 days to get the test result.

Continuous Radon Monitors

The other common short term test is continuous radon monitors. These are electronic devices that take one or multiple measurements per hour.

They are sophisticated machines that can also measure the indoor humidity, pressure, and temperature.

radon testing home inspection
Continuous Radon Monitor

Radon detectors also have tamper sensors which means that if the homeowner moves the radon monitor, the home inspector will know and can invalidate the result. If you are concerned that the seller may tamper the test, talk to your inspector about anti-tampering methods that they use.

Like the charcoal radon test, continuous radon monitors have to be picked up in 2-4 days. The test result is instant — the inspector may just need to connect it to their laptop.

Read Also: How To Inspect A Home Foundation?

What Causes Radon?

Radon gas is caused by the natural breakdown of uranium in the soil under and around the foundation.

Technically, radon is the radioactive decay product of Radium-266 which is part of the long decay chain of Uranium-238.

Radon gas in the outdoor air is harmless, but it can build up in some houses reaching hazardous levels.

radon testing home inspection
EPA map of radon zones (red is most potential for elevated radon levels)

The radioactive gas can seep into the home through an unsealed sump pump, small cracks in the foundation, and gaps in the foundation walls. It can also go into the home through plumbing and electrical wiring penetrations.

Some areas of the country are also more prone to elevated radon gas such as in the Northeast and Midwest of the USA. And even if your neighbor has low levels of radon detected, your home may be highly elevated — so it is really a house by house determination.

Read Also: 10 Home Inspection Tips For Sellers

How To Get Rid Of Radon Gas?

It is impossible to get rid of radon gas 100%, but it can be greatly reduced by installing a radon mitigation system. Radon mitigation systems cost typically between $750 to $1500 to install.

To find a list of qualified radon contractors and testers, you may also want to contact your state’s radon office.

How Radon Mitigation Systems Work

Basically, these systems consist of a PVC pipe that goes from the foundation of the home to the exterior. Somewhere along this PVC pipe will be a fan than is on 24-hours.

The fan creates a negative air pressure environment underneath the foundation sucking up any radon gas. And then the gas travels up the PVC pipe and to the outside (either on the side of the home or at the roof).

The radon fan is usually located on the side of the home but sometimes it is in the attic.

radon testing home inspection

Radon-Resistant Construction

In addition to radon mitigation systems, new homes can be built with radon-resistant construction techniques. These construction methods include having a vapor barrier and four inches of gravel installed prior to pouring the foundation.

It is also includes caulking all foundation openings and cracks with polyurethane caulking to help prevent radon gas seepage.

For older houses, homeowners can make sure to have a sealed sump pump, and to seal all pipe penetrations and foundation cracks with polyurethane caulking.

What Is The Cost For Radon Testing?

The cost for radon testing during home inspections will be about $75 to $150.

Home inspectors tend to give discounts for radon testing if it is performed as an extra service during the home inspection. If we do a stand alone radon test, we will likely charge more. You may also be interested in reading my guide on the cost of home inspections.

How Long Does A Radon Test Take?

The absolute shortest a radon test can take is 48 hours — this is the minimum time required. The longest a radon test can be left in a home is four days or 96-hours. I invite you to also read my guide on how long home inspections take.

If the home inspector used a continuous radon monitor, the test result can be the same day it is retrieved — it is just a matter of the inspector connecting the radon detector to their computer.

If it is a charcoal test packet that is sent to a laboratory, it can take a few days longer. The lab that I sent these charcoal test packets would email me the test result the same day that they received it.

Final Thoughts

Radon testing is a cheap and easy way to find out if your home has elevated radon levels prior to the closing.

If you don’t do radon testing, and then later find out that you have high radon levels — you will be on the hook for the radon mitigation system. But if you find out prior to the closing, you can ask the seller to pay for the system.

And besides the radon mitigation system, homeowners can also reduce radon levels by making sure the sump pump has a sealed lid. You can also caulk all cracks, openings, and crevices in the basement with polyurethane caulk to reduce radon seepage.

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