The hidden geology, the Sandhills, and the question locals still ask about SRS

If you live in Aiken County, there’s a good chance you’ve heard someone mention radon before. Maybe it came up during a home inspection. Maybe you saw one of the WRDW investigations. Or maybe you’ve simply noticed that Aiken keeps showing up on “high radon” lists across South Carolina.

But why?

Why does Aiken seem to have higher radon levels than many surrounding areas—including parts of Georgia just across the river?

The answer is part science, part geography, and part ongoing local debate.

First, What Exactly Is Radon?

Radon is a naturally occurring radioactive gas created when uranium in soil and rock breaks down over time. It rises through the ground and can enter homes through:

• Foundation cracks
• Crawl spaces
• Slab joints
• Plumbing openings
• Basements

You can’t see it, smell it, or taste it.

And according to the EPA, radon is the second leading cause of lung cancer in the United States, behind smoking.

Aiken County Has Some of the Highest Readings in South Carolina

A 2020 WRDW I-Team investigation found radon readings in Aiken County reaching as high as 74 pCi/L—far above the EPA action level of 4.0 pCi/L.

The investigation also reported that:

• Aiken County has some of the highest radon levels in South Carolina
• Some zip codes near New Ellenton and the Savannah River Site showed especially elevated readings
• Certain areas in Aiken tested higher than neighboring counties in Georgia

So what’s causing it?

The Biggest Reason: Aiken’s Unique Geology

Most experts agree the primary cause is natural geology.

Aiken sits near what geologists call the “Fall Line”—the transition area between South Carolina’s Coastal Plain and the Piedmont region.

That matters because:

• The Piedmont region contains uranium-bearing granite and metamorphic rock
• Uranium naturally breaks down into radon gas
• Aiken’s sandy soils make it easier for radon to move upward toward buildings

In simple terms:

Aiken has both the underground materials that create radon and the soil conditions that help it travel into homes.

The Sandhills Effect

Aiken is also part of South Carolina’s Sandhills region, an area made up of ancient coastal dunes and loose sandy soils.

Why does that matter?

Because sandy soil is:

• More porous
• Less compact
• Easier for gases to move through

That means radon can rise more easily from underground and collect beneath homes.

Compare that to denser clay-heavy soils in other regions, which can slow radon movement significantly.

Why Some Homes Test Worse Than Others

Even within Aiken County, two houses next door to each other can have completely different radon levels.

That’s because radon is also affected by:

• Foundation type
• Crawl spaces
• HVAC systems
• Home age
• Cracks in slabs
• Air pressure differences
• Winter “stack effect”

Ironically, some newer energy-efficient homes can trap radon more effectively because they’re sealed tighter.

What About the Savannah River Site?

This is where the conversation gets more controversial.

Some residents have long wondered whether the Savannah River Site (SRS) contributes to elevated radon levels in nearby areas.

SRS historically handled radioactive materials and nuclear weapons production, including uranium processing.

The WRDW investigation noted that some of the highest radon readings were found in zip codes closest to SRS.

However:

• There is no definitive scientific proof showing SRS directly causes residential radon levels in Aiken homes
• Most geologists still point to natural underground geology as the primary driver

Still, because SRS has a documented history involving radioactive materials in soil and groundwater, the question continues to come up locally.

Why Winter Makes Radon Even Worse

If you test your home in winter, you’ll often get higher readings.

That’s because:

• Homes stay sealed up
• Heating systems create pressure differences
• Warm indoor air pulls more radon upward from the soil

This “stack effect” can significantly increase indoor radon concentrations.

That’s one reason professionals often recommend winter as the best time to test.

So Should You Test Your Home in Aiken?

Honestly? Yes.

Even if:

• Your neighbor tested low
• Your home is brand new
• You don’t have a basement
• You live on a slab foundation

Radon levels vary house by house.

The only way to know your exposure is through testing.

Why More Aiken Residents Are Turning to EnviroPro 360

At EnviroPro 360, we help homeowners, renters, and property managers across Georgia and South Carolina understand what’s really happening in their indoor air.

We provide:

• Professional radon testing
• Fast, accurate reporting
• Guidance on mitigation options
• Local expertise specific to Aiken and CSRA conditions

Because when it comes to radon, guessing isn’t enough.

Schedule Your Radon Test Today

Aiken’s elevated radon levels aren’t just rumors—they’re backed by geology, testing data, and years of environmental concern.

The good news? Radon is detectable. And manageable.

Contact EnviroPro 360 today to schedule professional radon testing and protect your home from one of the region’s most overlooked environmental risks.