Posted on September 4th, 2025

 

When you think about making your home safe, it's necessary to consider every bit of information available that contributes to a healthier living space for you and your family. While visible issues like structural soundness, plumbing, and heating get immediate attention, radon levels can often fly under the radar because this gas is invisible and odorless. Have you thought about how significant an impact radon testing and mitigation can have on your home’s environment and value? 

 

Understanding Radon and Its Dangers

Learning about radon starts with recognizing that it is a naturally occurring radioactive gas produced by the decay of uranium in soil, rock, and water. It is colorless, tasteless, and odorless, which makes it difficult to detect without specialized equipment. Radon seeps into homes through foundation cracks, gaps around service pipes, sump pits, crawlspaces, and even through porous concrete. Any type of home can be affected, regardless of age or style, which is why routine testing matters for every homeowner.

The health concern comes from radon’s decay products. When inhaled, these radioactive particles can lodge in lung tissue and damage cells over time. Prolonged exposure increases the risk of lung cancer, and the risk climbs as indoor concentrations rise and exposure continues. People who spend long hours at home, including remote workers, young children, and retirees, can face higher cumulative exposure simply because of time spent indoors. 

 

Exploring Radon Levels in Homes

Radon levels vary widely from home to home, even among neighbors on the same street. Local geology plays a major role; areas with uranium-rich soils tend to show higher average levels. Homes across the Midwest often encounter elevated readings due to regional soil composition, and states like Illinois and Indiana have many counties designated as higher potential zones. That said, low-potential maps do not guarantee a low-radon home. 

How a home is built and operated also influences readings. Basements, which are in direct contact with soil, can create more entry points and more negative pressure that draws soil gases inward. Slab-on-grade homes and homes with crawlspaces can also have elevated levels, though the pathways differ: slab cracks, control joints, perimeter gaps, and uncovered or vented crawlspaces can all become entry routes. Ventilation patterns, weather systems, and seasonal changes shift indoor radon from week to week. Here’s how home features and conditions commonly shape radon levels:

• Contact with soil: Basements and crawlspaces increase pathways for soil gas to enter through cracks, joints, and gaps.

• Pressure differences: Exhaust fans, furnaces, and even wind can create suction that pulls soil gases indoors.

• Building materials and repairs: New concrete, settled slabs, or foundation changes can open fresh micro-cracks that alter airflow.

• Ventilation habits: Closed-up homes can experience higher concentrations, while strategic ventilation can lower short-term readings.

These factors interact in complex ways, which is why two neighboring houses can show very different results. A thoughtful look at the building’s design and use patterns helps interpret test results and decide on the right mitigation approach.

 

Safe Levels and EPA Recommendations

When discussing safe indoor air, it helps to anchor the conversation to established public health guidance. The Environmental Protection Agency (EPA) set an Action Level at 4.0 pCi/L (picocuries per liter). At or above this level, the EPA urges homeowners to take corrective steps to reduce exposure. The agency also suggests that homeowners consider action for readings between 2.0 and 3.9 pCi/L, since any amount of radon carries some risk over long periods. Other public health organizations share similar guidance: lower is better, and practical, permanent reductions are the goal.

Consider these practical points that put the EPA guidance into context:

• Action threshold (4.0 pCi/L): At this level, mitigation is strongly recommended to cut long-term risk.

• Consider action (2.0–3.9 pCi/L): Meaningful health benefits can still be gained by reducing levels into this range or below.

• No safe “zero” indoors: Outdoor air contains small amounts of radon; the focus is on lowering indoor concentrations as much as feasible.

• Retesting after changes: Major renovations, HVAC changes, or foundation work can shift readings and warrant a follow-up test.

Taking the guidance seriously helps you set realistic targets: aim to reduce radon to the lowest level that is practical for your home. Many well-designed, professionally installed systems routinely bring levels below 2.0 pCi/L and keep them there.

 

Testing and Measuring Radon Levels

Testing is straightforward and is the only reliable way to know your home’s radon level. Short-term test kits (typically 2–7 days) are a common first step because they are inexpensive and quick. Place the detector in the lowest level you regularly use, follow the label directions closely, and keep windows and exterior doors closed as instructed to get a valid snapshot. 

Here’s what to keep in mind as you plan and interpret radon testing:

• Choose the right test window: Short-term tests are great screenings; long-term tests better reflect yearly averages.

• Follow placement directions: Put the test in a regularly used room on the lowest lived-in level, away from drafts, heat, and humidity sources.

• Close-house conditions: Keep exterior doors and windows closed as instructed; this yields a valid comparison to action thresholds.

• Compare to EPA guidance: At or above 4.0 pCi/L calls for mitigation; between 2.0 and 3.9 pCi/L still merits action to reduce risk.

A clear testing plan paired with proper placement produces trustworthy results. After you receive readings, match them to the EPA thresholds and decide on next steps. If results are elevated, a follow-up confirmation or a professional continuous monitor assessment can provide a targeted mitigation plan.

 

Radon Assessment During Home Inspections

Real estate decisions benefit from transparent radon information. Including radon testing in a pre-listing inspection can prevent last-minute surprises during a buyer’s due diligence, and it signals that the seller values indoor air quality. Buyers gain confidence when they see documented low readings or a properly installed, active mitigation system with a visible manometer and labeled piping. Lenders and insurers increasingly recognize the importance of radon documentation as part of a home’s environmental profile, so clear records can help transactions move smoothly.

For buyers, a radon contingency allows time to test and, if needed, negotiate mitigation before closing. For sellers, proactive testing and, when indicated, timely mitigation can protect value and reduce the risk of delays. A well-designed system—often a sub-slab depressurization setup for slab or basement homes, or a sub-membrane depressurization system for crawlspaces—creates negative pressure under the foundation and vents soil gas safely above the roofline. 

 

Related: The Dangers of Radon Gas and How to Protect Yourself

 

Conclusion

Radon is an invisible hazard that can be present in any home, and the only way to know your level is to test. Learning how local geology, building features, and daily living patterns influence readings helps you choose the right testing approach and interpret the results with confidence. Clear benchmarks from public health guidance make decisions easier: reduce levels when they are high and keep retesting on a sensible schedule. 

At Will County Radon Mitigation, we focus on solutions that deliver measurable, lasting results. Having a reliable radon mitigation system installed by professionals is important for the health and safety of your household. Elevated radon levels pose significant risks, and our team, with NRSB certification and extensive experience, ensures that the installation process is quick and efficient.

Reach us at [email protected] or call (815) 693-1526 to schedule testing, request a bid, or discuss your options. We’re here to help you lower radon levels, protect your family’s health, and keep your home market-ready with clear documentation and steady, long-term performance.