50%tests ≥ 4 pCi/L
305tests on record
3.8median pCi/L
Zone 1EPA zone (1993 prediction)

What the data shows

Where Ouray County sits among Colorado's 64 counties with dataEach dot is a county's share of tests at or above 4 pCi/L · Colorado county radon test results, 2005–2025
0%20%40%60%

How Ouray County compares

Ouray County ranks 4 of 6 among its neighboursShare of tests at or above 4 pCi/L · Colorado county radon test results, 2005–2025 · whisker: 95% range
San Juan County64%Montrose County55%Hinsdale County53%Ouray County50%San Miguel County42%Gunnison County40%Colorado 46%
Data table
AreaTests ≥ 4 pCi/LTests
San Juan County64%108
Montrose County55%2,491
Hinsdale County53%88
Ouray County50%305
San Miguel County42%241
Gunnison County40%1,693
Colorado (64 counties)46%237,408

Same source as Ouray County.

What it means for your home

About 1 in 2 results in Ouray 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 →

Colorado licenses radon mitigators. Source

Buying or selling here

Since August 2023, Colorado home sale contracts must include the seller's known radon test, report and mitigation history and the state health department's radon brochure (SB23-206). Source

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

About this data

Source: Colorado county radon test results (Colorado Department of Public Health and Environment). Period: 2005–2025. Tests: 305. 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