Should you test for radon when buying or selling a home in Pierce County?
Radon is a naturally occurring radioactive gas, and according to the EPA it’s the second leading cause of lung cancer after smoking. You can’t see or smell it — testing is the only way to know a home’s level. Western Washington generally has lower radon levels than parts of eastern Washington, but individual homes vary, especially those with basements. Testing during a buyer’s inspection period is inexpensive and quick, and if levels are high, mitigation systems can usually reduce them.
Radon doesn’t come up in every Pierce County transaction, but it should come up in more of them — especially for homes with basements or finished lower levels. The good news: it’s easy to test, and if there’s a problem, it can usually be fixed.
Here’s what buyers and sellers should know. For the broader inspection process, see home inspection contingencies in Washington.
What radon is and why it matters
- Radon is a naturally occurring radioactive gas released from soil and rock.
- It enters homes through foundation cracks, gaps, sumps, and crawlspaces.
- The EPA says radon is the second leading cause of lung cancer after smoking.
- You can’t see or smell it. Testing is the only way to know.
The EPA recommends fixing a home if radon is at or above 4 picocuries per liter (pCi/L), and suggests considering fixing it between 2 and 4 pCi/L.
Is radon a problem in Pierce County?
Western Washington, including Pierce County, generally has lower radon levels than parts of eastern Washington and northern Idaho. But “generally lower” isn’t the same as “safe in every home.” Levels vary house to house, even on the same street, based on soil, construction, and ventilation. Homes with basements, daylight lower levels, or living space over unvented crawlspaces are the most worth testing.
For buyers: when and how to test
- Test during your inspection period. Many home inspectors offer radon testing or can refer a specialist.
- Short-term tests work for transactions. Continuous radon monitors typically run at least 48 hours and provide results quickly.
- Closed-house conditions matter. Windows and exterior doors generally stay closed (except normal entry and exit) before and during the test for accurate results — ask the seller to cooperate.
- Test the lowest livable level. That’s where readings are typically highest.
If results come back high, you can negotiate a mitigation system, a credit, or other terms within your inspection contingency.
For sellers: should you test first?
If your home has a basement or finished lower level, testing before listing can be smart. A low result reassures buyers. A high result gives you time to install a mitigation system on your schedule — rather than negotiating under pressure during the inspection period.
Answer the environmental questions on your Form 17 seller disclosure accurately, and if you have test results or a mitigation system, share the documentation. Our guide to pre-listing inspections covers other checks worth doing early.
What mitigation looks like
The most common fix is sub-slab or sub-membrane depressurization: a vent pipe and fan that pull radon from beneath the home and vent it outside. Crawlspace homes often get a sealed vapor barrier with a fan. A certified radon mitigation contractor can quote the cost, and a follow-up test confirms the system works.
Radon is one of several environmental checks for older homes — see buying an older home in Puyallup or Sumner and asbestos in Washington homes.
Frequently Asked Questions
What radon level is considered high?
The EPA recommends fixing a home at or above 4 pCi/L and suggests considering fixing levels between 2 and 4 pCi/L.
Is radon common in Pierce County?
Western Washington generally has lower radon levels than parts of eastern Washington, but individual homes vary. Testing is the only way to know a specific home’s level.
How long does a radon test take?
Short-term tests used in real estate transactions typically run at least 48 hours under closed-house conditions. Long-term tests run 90 days or more.
Can a high radon level be fixed?
Usually, yes. A certified mitigation contractor can install a system — commonly a vent pipe and fan — that draws radon from beneath the home and vents it outside.
A radon test is a small step that gives buyers peace of mind and helps sellers avoid surprises. If you’re buying or selling, schedule a call with The Barnard Group, or start with our Pierce County home selling guide.
About Josh Barnard
Josh Barnard is the founder of The Barnard Group and has spent over 20 years helping families navigate some of life’s biggest moments through real estate. Known for his “Work Hard. Be Kind.” approach, Josh combines expert market knowledge, innovative marketing, and genuine care to help homeowners make confident decisions about their next chapter. Whether someone is buying their first home, moving up, downsizing, or relocating to Pierce County, his mission is simple: serve people well, create unforgettable experiences, and help families build a life they love.
Sources: U.S. Environmental Protection Agency radon guidance. Not medical advice — consult the EPA, Washington State Department of Health, and a certified radon professional. Researched November 2, 2026.
