Your Neighbor's Radon Test Doesn't Tell You Anything About Your Home
Your neighbor got their radon test back and everything looked fine. So you're probably wondering if you still need to bother. The short answer is yes — and it's not just a formality. Radon levels can vary dramatically from one house to the next, even on the same street, which means your neighbor's results tell you almost nothing about what's happening under your own foundation.
Why Radon Doesn't Follow Property Lines
Radon is a naturally occurring radioactive gas that forms when uranium in soil and rock breaks down. It seeps up through the ground and into homes through foundation cracks, gaps around pipes, and other small openings. The amount that accumulates inside any given home depends on a combination of factors specific to that structure.
Soil composition is one of the biggest variables. Even in the same neighborhood, the soil under one house might have significantly higher uranium content than the soil under the house next door. Geology doesn't follow lot lines.
Foundation type matters, too. A house with a basement has different exposure dynamics than a slab-on-grade home or one built over a crawl space. The same is true for foundation age and condition, older foundations tend to have more cracks and entry points. Your neighbor's build and your build may look similar from the street and be completely different underground.
What the Numbers Actually Mean
The EPA recommends taking action when radon levels reach 4 picocuries per liter (pCi/L) or higher, though they note that levels between 2 and 4 pCi/L still carry some risk and mitigation is worth considering. There's no truly "safe" level of radon — the goal is to keep levels as low as reasonably achievable.
Nationally, the average indoor radon level is about 1.3 pCi/L. But averages don't mean much when the house-to-house variation is so wide. Some homes test under 1 pCi/L. Others come back at 10, 20, or even higher. Those homes aren't in radon hot zones, either — they're in ordinary neighborhoods where the house next door might test perfectly fine.
The Factors That Drive Radon Levels in Your Specific Home
Several things specific to your home determine how much radon accumulates indoors:
Soil type and uranium content under your foundation
Foundation type — basement, crawl space, or slab
Foundation condition — cracks, gaps, and openings where gas can enter
Ventilation and air pressure — homes with lower interior air pressure draw radon in more easily
Construction materials — some building materials, like certain concrete products, contain trace amounts of radon-producing minerals
None of these factors are shared with your neighbor, even if you live 30 feet apart. The only way to know what's happening in your home is to test your home.
How Radon Testing Actually Works
Testing is straightforward. Arrow uses professional-grade equipment to measure radon levels, typically over a 48-hour period. The test captures an average concentration over that window, which gives a much more accurate picture than a short-term snapshot.
Short-term tests are available as DIY kits at hardware stores, but they're sensitive to conditions like windows being open or weather changes during the test period. A professional test follows EPA-recommended closed-house protocols and gives you results you can actually rely on.
After testing, you'll receive a clear report showing your radon levels and whether mitigation is recommended. If levels are elevated, a radon mitigation system — typically a sub-slab depressurization system installed by a certified contractor — can reduce levels by up to 99%.
When to Test
Any homeowner who hasn't tested recently should. If you've never tested, now is the time. If you tested more than two years ago, it's worth retesting, radon levels can shift as a home settles, ventilation changes, or occupancy patterns change.
Testing is also standard practice before buying or selling a home. If you're a buyer, requesting a radon inspection alongside the general home inspection protects you from inheriting a problem you didn't know about.
The test takes less than a week and costs far less than the mitigation work you'd have to do if elevated levels go undetected for years.
If you're ready to schedule a professional radon test or want to talk through what the results would mean for your home, contact Arrow Inspection Services for a free consultation.
