Radon is often called the “silent killer” because you can’t see it, smell it, or taste it. This radioactive gas can accumulate in your home to dangerous levels without any obvious warning signs. While the only definitive way to know if your home has elevated radon is through testing, certain factors can indicate higher risk.
The Problem with Detecting Radon
Unlike carbon monoxide, which triggers detectors, or water damage, which leaves visible stains, radon provides no sensory clues. You won’t develop immediate symptoms from breathing radon gas. The health effects appear years or decades later in the form of lung cancer, making early detection through testing critical.
Despite the lack of physical symptoms, several characteristics can suggest your home may have elevated radon levels.
Risk Factors for High Radon Levels
Geographic Location
Your location plays a significant role in radon risk. North Carolina has 77 out of 100 counties with indoor radon levels exceeding the EPA action level. Areas with granite formations, including parts of Wake, Warren, Franklin, and Vance counties, show particularly high concentrations. However, every county in North Carolina has homes with elevated radon, so location alone doesn’t determine your risk.
Home Construction Type
Certain construction features increase the likelihood of radon accumulation:
- Homes with basements or crawl spaces: These areas have more contact with soil where radon originates.
- Slab-on-grade foundations: Cracks in concrete slabs provide direct pathways for radon entry.
- Older homes: Settling can create cracks and gaps that allow radon infiltration
- Homes with poor ventilation: Limited air exchange allows radon to concentrate indoors
Visible Foundation Issues
While radon itself is invisible, foundation problems that allow its entry may be visible:
- Cracks in basement walls or floors
- Gaps around utility pipes and wires
- Deteriorating mortar in stone foundations
- Exposed soil in crawl spaces
- Water seepage problems that indicate pathways for gas entry
Soil and Geology Indicators
The type of soil and rock beneath your home impact radon levels:
- Granite bedrock common in the Piedmont region
- Shale and phosphate deposits
- Uranium-rich soil
- Well-drained, permeable soil that allows easy gas movement
- Areas with previous mining activity
Neighbor Test Results
If homes near yours have tested high for radon, your property may also have elevated levels. Radon concentrations can vary significantly even between adjacent properties due to differences in soil composition, construction, and ventilation. However, neighborhood patterns provide useful context for your risk level.
Time-Based Patterns
Radon levels fluctuate based on several factors:
- Seasonal changes: Winter months often show higher readings due to closed windows and increased heating that creates negative pressure.
- Weather conditions: Low barometric pressure can pull more radon into homes.
- HVAC system operation: Heating and cooling systems affect air pressure and radon infiltration.
These patterns don’t tell you if you have high radon, but they explain why levels change throughout the year.
Home Age Doesn’t Guarantee Safety
Both new and old homes can have radon problems. While newer homes may have fewer cracks and better sealing, they can also be built more airtight, which prevents radon from escaping once it enters. Older homes may have more foundation deterioration but often have better natural ventilation.
The Only True Indicator: Testing
None of these signs definitively prove your home has elevated radon levels. The EPA recommends that all homes be tested, regardless of age, location, or construction type. Testing is the only way to know your radon level with certainty.
Short-term tests take 2-7 days and provide a snapshot of radon levels. Long-term tests run for 90 days or more and give a more accurate average. Professional testing offers the most reliable results, though DIY kits are also available.
What to Do Next
If your home shows multiple risk factors for radon, don’t wait to test. The North Carolina Radon Program offers resources for affordable testing. If results show levels at or above 4 pCi/L, professional mitigation can reduce concentrations by up to 99%.
Contact AAA Environmental Solutions to schedule professional radon testing for your Raleigh-area home. Knowing your radon level is the first step in protecting your family from this preventable health risk.