Mercer Island, WA Radon Mitigation and Testing

Q: What EPA Radon Zone is Mercer Island in?

Mercer Island is in King County, EPA Zone 3.

Q: How much does radon mitigation cost in Mercer Island?

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

King County

EPA Zone 3

This affluent Seattle Metro community sits on an island in Lake Washington within King County, where glacial deposits and marine sediments create generally low radon conditions. Testing data for the 98040 zip code is currently unavailable, but western Washington's EPA Zone 3 classification indicates relatively low radon potential. Island properties should still consider occasional testing, especially those built on elevated sites or with unusual ventilation systems.

Mercer Island, WA Radon Mitigation

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

Mercer Island, WA Radon Testing

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

Mercer Island Radon Facts

Key details about the radon risk profile for Mercer Island and the 98040 zip code area.

EPA Radon Zone

Zone 3 — Low Risk

County

King County, WA

Zip Code

98040

Predicted Screening Level

< 2.0 pCi/L (Zone 3)

Mercer Island and the 98040 zip code are located in King County, which has an EPA assigned Radon Zone of 3. A radon zone of 3 predicts an average indoor radon screening level less than 2 pCi/L. The EPA recommends testing every home regardless of zone classification.

Radon FAQ for Mercer Island, WA

What EPA Radon Zone is Mercer Island in?

Mercer Island and the 98040 zip code are in King County, which has an EPA assigned Radon Zone of 3. A zone of 3 predicts an average indoor radon screening level less than 2 pCi/L.

How much does radon mitigation cost in Mercer Island?

Radon mitigation in Mercer Island 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 Mercer Island?

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