What Are High Radon Levels? The Complete Guide Every Illinois Homeowner Should Read

Professional Radon Testing by Quality Environmental Testing (QET)

Whether you're buying a home, selling one, or simply trying to create a healthier living environment for your family, you've probably heard someone mention radon. It's one of the most common environmental concerns discussed during real estate transactions, yet it's also one of the least understood.

Many homeowners assume that if they've never noticed a problem, there isn't one. Unfortunately, radon doesn't work that way.

Unlike mold, water damage, or other household issues that often leave visible clues, radon is completely invisible. It has no odor, no taste, and no color. A home can have dangerously elevated radon levels for decades without the occupants ever knowing.

At Quality Environmental Testing (QET), we've been providing professional environmental testing throughout Lockport and the southwest Chicagoland area since 2002. One of the questions we hear more than almost any other is:

"How do I know if my home has high radon levels?"

The honest answer is simple.

You can't know without testing.

Understanding what radon is, how it enters a home, what levels are considered concerning, and how professional testing works can help you make informed decisions that protect your family and your investment.

Let's start with the basics.

What Is Radon?

Radon is a naturally occurring radioactive gas produced during the breakdown of uranium found in soil and rock beneath the earth's surface.

While "radioactive gas" certainly sounds alarming, the presence of radon outdoors isn't usually a problem. Once released into open air, it quickly disperses into the atmosphere where concentrations become extremely low.

The concern begins when radon becomes trapped inside buildings.

Every home sits on soil. As uranium naturally decays underground, radon gas is continuously produced. That gas moves upward through the soil looking for an escape path. If a home is built above it, the building often becomes that path.

Because homes naturally create lower air pressure than the surrounding soil, they actually draw soil gases inward. This phenomenon, known as the stack effect, causes radon to be pulled through even tiny openings in the foundation.

Since radon is colorless, odorless, and tasteless, homeowners have no way of detecting it without specialized equipment.

That is why radon has earned its reputation as the invisible health hazard.

What Are High Radon Levels?

Radon concentrations are measured in picocuries per liter of air (pCi/L).

Although any amount of radon carries some level of risk, health organizations have established action levels based on decades of scientific research.

According to the U.S. Environmental Protection Agency (EPA):

• Below 2.0 pCi/L is considered relatively low.

• Between 2.0 and 4.0 pCi/L deserves attention and often warrants additional evaluation.

• 4.0 pCi/L or higher is the EPA's recommended action level for mitigation.

It's important to understand what this means.

The EPA does not consider levels below 4.0 pCi/L to be completely safe. Rather, 4.0 pCi/L is the point where the health risks become significant enough that corrective action is strongly recommended.

Many homeowners choose to mitigate even lower readings to further reduce long-term exposure, especially when young children or individuals with respiratory concerns live in the home.

Think of it similarly to cholesterol or blood pressure. Lower numbers generally mean lower risk.

Why Radon Levels Vary So Much

One of the biggest misconceptions about radon is that every home in the neighborhood will have similar readings.

In reality, two homes built side by side can have dramatically different radon levels.

Several factors influence how much radon enters a home:

• Soil composition

• Natural uranium concentration

• Moisture content in the soil

• Foundation construction

• Cracks and openings

• HVAC operation

• Seasonal weather

• Indoor air pressure

This is why county radon maps should only be viewed as general guidance.

Even if your neighbor tested below the EPA action level, your home could test much higher—or vice versa.

Every home is unique.

How Does Radon Get Into Your Home?

Radon follows the path of least resistance.

As your home naturally draws air upward and out through the roof, replacement air is pulled from the lowest level of the structure. Along with that air comes soil gas.

Common radon entry points include:

• Foundation cracks

• Expansion joints

• Sump pump basins

• Utility penetrations

• Crawl spaces

• Floor drains

Even homes with beautifully finished basements are not immune. Dry basements, new homes, old homes, homes with poured concrete foundations, and homes with block foundations can all experience elevated radon levels.

Why Newer Homes Can Sometimes Test Higher

Many homeowners assume an older home is more likely to have radon because of foundation cracks.

Ironically, newer homes can sometimes produce higher readings.

Modern construction methods focus heavily on energy efficiency. Homes are built tighter than ever before, reducing natural air exchange with the outdoors.

While this saves energy, it can also trap radon inside.

Additionally, tightly sealed homes often create stronger negative air pressure, pulling more soil gases through the foundation.

This is one reason why newer homes should never be assumed to be radon-free.

Every home deserves testing.

Do High Radon Levels Affect Your Health?

Yes.

Radon exposure has been extensively studied for decades, and the evidence is overwhelming.

The EPA identifies radon as the second leading cause of lung cancer in the United States, behind smoking, and the leading cause among people who have never smoked.

When radon gas breaks down, it produces radioactive particles that become suspended in the air. After these particles are inhaled, they can lodge within lung tissue, where they continue releasing small amounts of radiation over time. Years of repeated exposure increase the likelihood of cellular damage that may eventually lead to lung cancer.

Unlike many environmental hazards, radon exposure usually produces no immediate symptoms.

People often live in homes with elevated radon for years without realizing they have been exposed.

That silent nature is what makes testing so important.

Who Faces the Greatest Risk?

Although anyone exposed to elevated radon levels carries some risk, certain groups are more vulnerable.

• Smokers and former smokers

• Children, because they breathe faster and their lungs are still developing

• Individuals who spend significant time in finished basements or other lower levels of the home

The amount of time spent breathing elevated radon is one of the biggest factors influencing long-term risk.

How Can You Tell If Your Home Has High Radon Levels?

The simple answer is this:

You can't tell without testing.

Unlike mold, moisture problems, or poor indoor air quality, radon leaves no visible signs behind. You won't see staining on walls, smell an unusual odor, or notice changes in your home's appearance. A house with elevated radon levels can look perfectly clean and well maintained.

Many homeowners assume that because their home is newer, has never had water issues, or because a neighbor's home tested low, they don't need to worry about radon. Unfortunately, none of those assumptions are reliable.

Radon levels can vary dramatically from one home to the next—even homes built by the same builder, on the same street, or sharing a property line.

The only way to accurately determine your home's radon level is through professional testing.

Why Professional Radon Testing Matters

Professional radon testing is the most reliable way to determine the radon concentration inside your home. Because radon levels naturally fluctuate throughout the day, obtaining an accurate measurement requires professional equipment, proper monitor placement, and testing performed according to established industry standards.

At Quality Environmental Testing (QET), we use professionally calibrated SunRADON 1028-XP Continuous Radon Monitors, one of the most trusted instruments used by radon professionals. These monitors record hourly radon measurements throughout the required 48-hour testing period, providing a complete picture of how radon levels change over time.

Proper placement is just as important as the equipment itself. Industry protocols specify where the monitor should be placed within the home to obtain representative results. Windows, exterior doors, HVAC vents, ceiling fans, and the home's layout are all considered before testing begins.

Once the monitoring period is complete, QET downloads the data and prepares a detailed electronic report showing the average radon concentration, hourly readings, testing conditions, and all information needed to understand the results with confidence.

When you're making decisions about your family's health or one of the largest investments you'll ever own, professional testing provides the accurate, unbiased information you need.

What Happens During a Professional Radon Test?

The testing process is simple and non-invasive.

A certified QET technician places the continuous radon monitor in the appropriate location, typically the lowest livable level of the home. The monitor remains in place for a minimum of 48 hours while recording hourly radon concentrations.

During the testing period, closed-house conditions are maintained to ensure accurate results. Once the test is complete, the monitor is retrieved, the data is analyzed, and a detailed electronic report is provided.

Understanding Your Radon Test Results

If your home's average radon level is below the EPA action level, you can have greater confidence in your indoor environment, although periodic retesting is still recommended, especially after major renovations or changes to the home's ventilation.

If your home tests at 4.0 pCi/L or higher, the EPA recommends installing a radon mitigation system to reduce indoor radon levels.

Fortunately, radon mitigation is a proven solution that has successfully lowered radon levels in millions of homes.

What Should You Do If Your Home Tests High?

First, don't panic.

A high radon reading doesn't mean your home is unsafe forever. It simply means you've identified a problem that can typically be corrected.

The next step is to contact a qualified radon mitigation contractor. Most systems use sub-slab depressurization to safely vent radon gas from beneath the foundation before it enters the home.

After mitigation is complete, the home should always be retested to confirm the system is effectively reducing radon levels.

Why Independent Testing Matters

At Quality Environmental Testing (QET), we are a testing-only company.

We do not install radon mitigation systems.

That means our recommendations are based solely on accurate testing data—not on selling additional services.

Since 2002, homeowners, real estate professionals, attorneys, and property managers throughout Lockport and the southwest Chicagoland area have trusted QET to provide objective, independent radon testing.

Our job is simple: deliver accurate results so you can make informed decisions with confidence.

Protect Your Home. Protect Your Family.

Radon is one of the few environmental hazards that can pose a serious long-term health risk without any warning signs.

Fortunately, it's also one of the easiest indoor air quality issues to identify through professional testing.

Whether you're buying a home, selling a home, or simply haven't tested in several years, knowing your radon level is one of the most important steps you can take to protect your family and your investment.

At Quality Environmental Testing (QET), we've proudly provided independent professional radon testing throughout Lockport and the surrounding southwest Chicagoland communities since 2002.

Using calibrated SunRADON 1028-XP Continuous Radon Monitors, experienced technicians, and detailed electronic reporting, we provide the accurate, unbiased results homeowners deserve.

If you've never had your home professionally tested for radon—or it's been several years since your last test—contact Quality Environmental Testing today. You'll gain the confidence that comes from knowing exactly what's in the air your family breathes every day.

Need Professional Radon Testing?

Reading about radon is a great first step, but the only way to know your home's radon level is through professional testing.

Quality Environmental Testing (QET) has been providing licensed, independent radon testing throughout Lockport and the southwest Chicagoland area since 2002.

👉 Schedule your Radon Test