16%tests ≥ 4 pCi/L
372tests on record
—median pCi/L
Zone 3EPA zone (1993 prediction)

Test results in Chelan County

ResultShareEPA guidance
Below 2 pCi/L65%Below EPA's levels
2 to 4 pCi/L20%Consider fixing
4 pCi/L or more16%EPA recommends fixing

What the data shows

Where Chelan County sits among Washington's 39 counties with dataEach dot is a county's share of tests at or above 4 pCi/L · Radon test results by county (Washington Tracking Network), 2000–2025
0%20%40%60%

How Chelan County compares

Chelan County ranks 4 of 7 among its neighboursShare of tests at or above 4 pCi/L · Radon test results by county (Washington Tracking Network), 2000–2025 · whisker: 95% range
Okanogan County31%Douglas County23%Kittitas County18%Chelan County16%Skagit County6%King County4%Snohomish County2%Washington 19%
Data table
AreaTests ≥ 4 pCi/LTests
Okanogan County31%588
Douglas County23%101
Kittitas County18%209
Chelan County16%372
Skagit County6%394
King County4%11,972
Snohomish County2%2,799
Washington (39 counties)19%64,932

Same source as Chelan County.

What it means for your home

About 1 in 6 results in Chelan County were at or above 4 pCi/L, where the EPA recommends a fix. Only a test shows your own home's level.

Levels in pCi/L from the EPA. The WHO reference level is 100 Bq/m³, about 2.7 pCi/L.

Test your home

Start with a short-term test (2–90 days) and confirm a result of 4 pCi/L or more with a second test. EPA guide

Sponsored: we earn a commission on purchases through these links. We haven't tested Airthings monitors yet.

Prefer a digital monitor? See Airthings radon monitors, or enter code radonbycounty-10OFF at their discount store for 10% off.

Fixing high radon

No local job records yet. National range: $800–$2,500, average $1,200 (EPA, 2003). Cost guide →

Washington doesn't license radon mitigators; look for NRPP or NRSB certification. Source

Buying or selling here

Washington's seller disclosure statement asks whether the seller knows of substances that may be environmental concerns, including radon gas (RCW 64.06.020). Source

Checked against the official text on 2026-11-03. Not legal advice.

About this data

Source: Radon test results by county (Washington Tracking Network) (Washington State Department of Health). Period: 2000–2025. Tests: 372. Read the methodology →

These are voluntary and real-estate tests, not a random sample of homes, so they describe tested homes rather than every home.

About this page

Published by Ray Roman, editor of Radon by County. Figures are loaded from the cited source and spot-checked against it. Editorial policy · About us