Radon Testing: How It Works and How to Understand the Results

Radon cannot be identified by sight, smell, or taste. Testing is therefore necessary to determine whether radon is present at elevated concentrations inside a home.

Professional radon testing uses designated monitoring equipment and specific testing conditions to measure radon concentrations. For homeowners, understanding how the testing process works, how to prepare the property, and how results are reported can make the process easier to navigate.

What Is a Radon Test?

A radon test measures the concentration of radon in the air inside a home. Radon concentrations are measured in picocuries per liter of air, written as pCi/L.

Professional testing is designed to provide information about the radon level in a specific home under the conditions present during the testing period. Because radon concentrations can vary, following the appropriate testing conditions is an important part of obtaining useful results.

How Is a Home Prepared for Radon Testing?

A typical short-term radon test requires closed-building conditions before and during the test.

Homeowners should generally:

• Keep exterior windows and doors closed for at least 12 hours before testing begins and throughout the testing period.
• Continue normal heating and cooling operation.
• Discuss systems that continuously bring outdoor air into the home with the inspector before testing.
• Avoid using whole-house or window fans that bring substantial amounts of outdoor air into the home.
• Avoid disturbing or moving the testing equipment.
• Follow any additional instructions provided by the testing professional.

Normal entry and exit are permitted, but exterior doors should be closed promptly.

Testing conditions can vary depending on the property, equipment, weather, and testing protocol. Homeowners should follow the specific instructions provided for their test.

Where Is Radon Testing Equipment Placed?

Radon testing equipment is placed in a designated location within the home and should remain there throughout the testing period.

The equipment should not be moved, disturbed, or otherwise interfered with during testing. Maintaining the designated testing conditions helps ensure that the test measures the home under the intended conditions.

How Long Does a Radon Test Take?

The client information provided for this service describes typical short-term testing but does not specify a standard testing duration. The testing period can depend on the equipment and testing protocol being used.

Homeowners should follow the testing instructions provided by 5D Home Inspections for the specific property.

How Are Radon Results Measured?

Radon concentrations are reported in picocuries per liter of air, or pCi/L.

The EPA recommends taking action to reduce radon when testing identifies levels of 4.0 pCi/L or higher. Because there is no known completely risk-free level of radon exposure, the EPA also recommends considering mitigation when levels are between 2.0 and 4.0 pCi/L.

The appropriate next step depends on the measured concentration and the circumstances of the property.

What Does a High Radon Result Mean?

An elevated radon result indicates that the home has a radon concentration that may warrant further action.

The amount of risk associated with radon exposure depends on several factors, particularly the radon concentration in the home, the duration of exposure, and whether an individual smokes or has smoked.

When elevated concentrations are identified, a qualified radon mitigation professional can evaluate the property and recommend appropriate measures to reduce radon levels.

Can a Home Have Radon Even If Nearby Homes Do Not?

Yes. Neighboring properties can have significantly different radon levels.

A home’s radon level cannot be reliably determined based on the results of a nearby property. Testing the individual home provides information specific to that property.

Does the Age or Type of Home Affect Whether It Needs Radon Testing?

Elevated radon can occur in new homes and older homes. It can also occur in homes with basements, crawlspaces, or slab-on-grade construction.

The home’s appearance, age, or condition cannot reliably determine whether elevated radon is present. Testing is the way to determine the radon concentration inside the property.

Why Is Radon Testing Important in New Jersey?

Elevated radon levels have been found in homes in every New Jersey county. The NJDEP recommends testing all homes, including homes located in areas classified as having low or moderate radon potential.

This makes testing relevant across New Jersey, regardless of whether a particular property appears likely to have elevated radon.

Professional Radon Testing for Homeowners

5D Home Inspections provides professional radon testing that requires minimal disruption to the home. Testing gives homeowners measurable information about the radon concentration inside the property.

Because radon cannot be detected through normal sight, smell, or taste, testing is the most direct way to determine whether elevated concentrations are present. When results indicate elevated levels, homeowners can use that information to determine whether further evaluation by a qualified radon mitigation professional is appropriate.