What Causes High Radon Levels in Homes?

Radon is a colorless, odorless, radioactive gas that can accumulate inside homes and pose serious long-term health risks. While radon is naturally present in the environment, certain conditions can cause it to build up to dangerous levels indoors. Understanding what causes high radon levels is the first step toward protecting your home and your health.

At Quality Environmental Testing Inc., we specialize in professional radon testing to help homeowners make informed decisions about indoor air quality.

1. Soil and Rock Beneath Your Home

The biggest factor influencing radon levels is the geology beneath your home. Radon is produced from the breakdown of uranium in soil, rock, and groundwater. Homes built on granite, shale, or phosphate-rich rock are more likely to experience elevated radon levels. Even neighboring homes can have vastly different readings depending on how radon moves through the ground beneath them.

2. Soil Permeability

Porous soils like gravel and sand allow radon to move more freely toward the surface. The more easily radon travels through the soil, the greater the chance it can seep into your home through foundation cracks and gaps.

3. Home Construction and Foundation Type

Your home’s construction plays a major role in how radon enters. Common entry points include:

• Cracks in basement floors and walls

• Gaps around pipes and utility lines

• Openings in sump pump pits or floor drains

• Crawl spaces with exposed dirt

Homes with basements or crawl spaces are particularly vulnerable. Even newer homes built with radon-resistant features can develop problems over time if those features fail or degrade.

4. Air Pressure and Ventilation

Radon is often pulled into homes due to air pressure differences between indoor and outdoor environments. This effect is strongest in colder months when warm air rises inside the house, creating a vacuum that draws radon from the soil.

Poor ventilation can trap radon indoors, allowing levels to build up. Sealing your home too tightly without a proper ventilation plan can unintentionally increase radon concentrations.

5. Seasonal and Weather Changes

Radon levels can fluctuate with the seasons. You may notice higher readings in:

• Winter, when windows are closed and heating systems increase indoor air pressure differentials

• Rainy or snowy conditions, which saturate the soil and force radon upward

• Low barometric pressure, which can draw more radon into lower parts of the home

Because of these variables, long-term radon testing provides the most accurate picture of your home’s exposure.

6. Well Water and Building Materials

If your home uses well water, radon can be released into the air during showering, washing, or cooking. While this is less common, it can contribute to elevated indoor radon levels, especially in homes with high water usage.

Some building materials—like granite countertops or concrete blocks—can emit small amounts of radon. In most cases, these are minor sources, but in tightly sealed spaces or in large quantities, they can add to the problem.

Protect Your Family with Professional Radon Testing

The only way to know your home’s radon level is to test. Whether you're buying a new home, remodeling your basement, or simply want peace of mind, radon testing is a smart investment.

At Quality Environmental Testing Inc., we offer accurate, affordable, and certified radon testing services for homeowners, real estate transactions, and property managers. If high levels are detected, we’ll guide you through the next steps with expert recommendations.

Schedule your radon test today and take control of your indoor air quality.