Thornton, WA Radon Mitigation and Testing

Q: What EPA Radon Zone is Thornton in?

Thornton is in Whitman County, EPA Zone 2.

Q: How much does radon mitigation cost in Thornton?

Radon mitigation typically costs between $800 and $2,000. Most standard systems fall in the $1,000-$1,500 range.

Whitman County

EPA Zone 2

Situated in Whitman County within the Palouse region of southeastern Washington, Thornton sits over loess soils and basalt formations that can produce variable radon conditions. Most homes in the area feature crawl space or slab construction typical of rural Washington building practices. Given the limited radon testing data available for this small farming community, homeowners should prioritize testing to determine individual property radon levels.

Thornton, WA Radon Mitigation

Professional radon mitigation is the most effective way to permanently lower radon levels and protect your household.

Thornton, WA Radon Testing

Finding qualified radon testing professionals is the first step toward protecting your home.

Thornton Radon Facts

Key details about the radon risk profile for Thornton and the 99176 zip code area.

EPA Radon Zone

Zone 2 — Moderate Risk

County

Whitman County, WA

Zip Code

99176

Predicted Screening Level

2–4 pCi/L (Zone 2)

Thornton and the 99176 zip code are located in Whitman County, which has an EPA assigned Radon Zone of 2. A radon zone of 2 predicts an average indoor radon screening level between 2 and 4 pCi/L. The EPA recommends testing every home regardless of zone classification.

Radon FAQ for Thornton, WA

What EPA Radon Zone is Thornton in?

Thornton and the 99176 zip code are in Whitman County, which has an EPA assigned Radon Zone of 2. A zone of 2 predicts an average indoor radon screening level between 2 and 4 pCi/L.

How much does radon mitigation cost in Thornton?

Radon mitigation in Thornton typically costs between $800 and $2,000. Most homes with standard basements can be mitigated with a sub-slab depressurization system in the $1,000–$1,500 range. Factors that can increase cost include complex foundations, crawl spaces, or very high radon levels.

Should I test for radon if I'm buying a home in Thornton?

Yes. Radon testing should be part of every home purchase. A short-term radon test is typically included as part of the home inspection process and costs $150–$250. If elevated levels are found, you can negotiate mitigation as part of the sale.

Most Active Radon Markets in Washington

Cities with the most user-submitted radon test data in the state.

City	Avg User Radon Level	Submissions
Vancouver	6.56 pCi/L	9
Kent	3.60 pCi/L	5
Seattle	5.25 pCi/L	4
Olympia	5.00 pCi/L	4
Bellevue	3.75 pCi/L	4
Spokane	11.67 pCi/L	3
Camas	8.00 pCi/L	3
Centralia	7.00 pCi/L	3
Bellingham	4.50 pCi/L	2
Kirkland	4.50 pCi/L	2
Washougal	8.00 pCi/L	1
Ridgefield	5.00 pCi/L	1
Moses Lake	No submissions	0