Colfax, WA Radon Mitigation and Testing

Q: What EPA Radon Zone is Colfax in?

Colfax is in Whitman County, EPA Zone 2.

Q: How much does radon mitigation cost in Colfax?

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 Washington's Palouse region, Colfax sits on loess deposits over basalt bedrock that characterize the rolling wheat country of southeastern Washington. While radon testing data for the 99111 zip code is limited, the geological conditions and housing patterns suggest homeowners should consider individual testing. The community's mix of historic homes and agricultural properties means radon exposure can vary significantly based on construction characteristics and foundation types.

Colfax, WA Radon Mitigation

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

Colfax, WA Radon Testing

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

Colfax Radon Facts

Key details about the radon risk profile for Colfax and the 99111 zip code area.

EPA Radon Zone

Zone 2 — Moderate Risk

County

Whitman County, WA

Zip Code

99111

Predicted Screening Level

2–4 pCi/L (Zone 2)

Colfax and the 99111 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 Colfax, WA

What EPA Radon Zone is Colfax in?

Colfax and the 99111 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 Colfax?

Radon mitigation in Colfax 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 Colfax?

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