Radon FAQs

Radon is a naturally occurring, radioactive gas that forms from the decay of uranium found in soil, rock, and water. It is colorless, odorless, and tasteless, making it completely undetectable without proper testing. Radon can seep into homes and buildings through cracks in foundations, floors, and walls. Because it cannot be seen or smelled, many homeowners are unaware of dangerous levels building up in their homes.

Although it is the heaviest naturally occurring gas, radon still circulates freely through the soil and air. It is produced naturally as uranium in the earth's crust breaks down over time. Because radon is a noble gas, it does not chemically bond with other elements, allowing it to remain unreactive as it moves through the environment.

Radon is the second leading cause of lung cancer in the United States, responsible for approximately 21,000 deaths each year according to the EPA. When radon gas is inhaled, it breaks down into radioactive particles that can become trapped in the delicate tissues of the lungs. Over time, these particles release small bursts of ionizing radiation that can damage lung tissue and lead to the development of cancer.

The risk is cumulative, meaning it increases significantly with prolonged exposure to elevated radon levels over months and years. There are typically no immediate symptoms of radon exposure, making regular testing the only way to detect danger.

The EPA recommends taking action to reduce radon levels in your home if the concentration reaches 4.0 pCi/L (picocuries per liter) or higher. However, there is no completely safe level of radon, as even lower concentrations carry some degree of risk. The EPA also suggests considering mitigation if levels fall between 2.0 and 4.0 pCi/L. The average indoor radon level in the U.S. is about 1.3 pCi/L, while outdoor air typically measures around 0.4 pCi/L.

Radon enters homes primarily through the path of least resistance from the soil and rock beneath the foundation, driven by the pressure differential between the ground and the interior of the home. The inside of a building is often at slightly lower pressure than the surrounding soil, creating a vacuum effect that actively draws radon gas inward. Common entry points include:

• Cracks in concrete slab floors and foundation walls
• Construction joints
• Gaps around service pipes
• Sump pits and floor drains
• Crawl space soil
• Hollow block foundation walls
• Well water

Homes with basements or crawl spaces are particularly susceptible because they have more contact with the soil where radon originates.

Every home should be tested for radon regardless of its age, location, or construction type. The EPA recommends testing every two years, or any time significant renovations are made to a home. It is especially important to test when buying or selling a home, as radon levels are a key factor in real estate transactions. Testing during the colder months when windows and doors are kept closed tends to provide the most accurate representation of everyday exposure levels.

A radon mitigation system works by creating negative pressure beneath the foundation, which prevents radon gas from being drawn into the home.

• A technician drills a hole through your basement floor or concrete slab to reach the soil underneath.
• A PVC pipe is inserted into this hole and routed up through the house (or outside) to an exit point above the roofline.
• A specialized, continuously running fan is connected to the pipe, usually in the attic or outside the living space.
• The fan creates a negative pressure (a vacuum) beneath the slab, drawing the radon gas out of the soil before
• The gas is pulled up through the pipe and safely vented into the outside air above the roof, where it quickly dissipates to harmless levels.

Opening windows and increasing ventilation can temporarily dilute radon concentrations, but it is not a reliable or long-term solution. Radon levels will return to normal shortly after windows are closed, making this an impractical approach for most climates. Additionally, certain weather conditions and wind patterns can actually increase radon entry when windows are open. A professionally installed mitigation system is the only proven, permanent solution for elevated radon levels.

Yes, radon levels in a home are not static and can fluctuate significantly based on a wide range of environmental, structural, and behavioral factors. Because of this variability, periodic retesting is essential even in homes where radon levels have previously tested below the EPA action level. Key factors that can cause radon levels to change over time include:

• Seasonal changes: Levels are typically higher in winter when homes are sealed and lower in summer when ventilation increases.
• Weather patterns: Low barometric pressure and storms can increase the rate at which radon is drawn from the soil.
• Changes in home construction: Finishing a basement, adding an addition, or sealing the home for energy efficiency can all impact radon concentrations.
• Foundation settling and cracking: As homes age, new cracks and gaps can develop, creating additional radon entry points.
• Changes to HVAC systems: New furnaces, exhaust fans, or whole-house ventilation systems can alter the pressure balance within a home.
• Landscaping and grading changes: Alterations to the soil around a home's foundation can affect how radon migrates through the ground.
• Mitigation system wear: A fan that is losing efficiency will reduce the system's effectiveness over time.

Newer homes may be built with radon-resistant construction techniques, such as gravel layers, plastic sheeting, and rough-in pipes beneath the slab. However, these passive measures do not guarantee that radon levels will remain below the EPA action level. Without an active fan, radon-resistant features may only partially reduce concentrations. Even newly constructed homes should be tested, and a fan can easily be added to an existing rough-in system if elevated levels are detected.

Yes, radon is a significant concern in North Dakota, as the state has some of the highest radon levels in the United States. In fact, the U.S. Environmental Protection Agency (EPA) classifies all 53 counties in North Dakota as Zone 1, indicating the highest potential for elevated radon gas. Because the radioactive gas is colorless, odorless, and can easily seep into homes through foundation cracks, the North Dakota Department of Environmental Quality strongly recommends that all residents test their homes. Consistent exposure to these high levels poses a serious health risk, as radon is the leading cause of lung cancer among non-smokers.