Radon in ZIP code 99251
Last updated
ZIP 99251 lies entirely in Spokane County, Washington. EPA’s radon zone for this area: Zone 1, highest potential.
Predicted average indoor screening level above 4 pCi/L.
What this means for homes in 99251
EPA built its zone map county by county in 1993, so every address in 99251 shares Spokane County’s prediction. The zone is a starting point, not a measurement of your house. Zone 1 areas like this one have a high share of homes above 4 pCi/L, so testing is a priority.
Next: read how to test your home, then check the number with the level calculator.
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Nearby ZIP codes in Spokane County
Washington radon help
WA State Department of Health, Community and Environment: Radon (360-236-3200) can help with test kits, local data and credentialed professionals: doh.wa.gov/community-and-environment/contaminants/radon.
Frequently asked questions
What is the radon zone for ZIP code 99251?
ZIP 99251 lies in Spokane County, which EPA places in Zone 1 (highest potential).
Should I test for radon in 99251?
Yes. EPA recommends testing every home regardless of zone, because radon varies from house to house. Fix the home if a confirmed result is 4 pCi/L or higher, and consider fixing between 2 and 4 pCi/L.
Free checklist · PDF
Radon Test Checklist
A one-page, step-by-step checklist for running a home radon test right the first time, and what to do with the number.
- Short-term vs. long-term test: which to use
- Closed-house conditions and where to place the kit
- What 2, 4 and 8 pCi/L mean and when to fix
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