33%tests ≥ 4 pCi/L
75tests on record
1.7median pCi/L
Zone 2EPA zone (1993 prediction)

What the data shows

Where Conejos 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 Conejos County compares

Conejos County ranks 3 of 5 among its neighboursShare of tests at or above 4 pCi/L · Colorado county radon test results, 2005–2025 · whisker: 95% range
Costilla County54%Rio Grande County37%Conejos County33%Archuleta County33%Alamosa County27%Colorado 46%
Data table
AreaTests ≥ 4 pCi/LTests
Costilla County54%26
Rio Grande County37%428
Conejos County33%75
Archuleta County33%1,030
Alamosa County27%168
Colorado (64 counties)46%237,408

Same source as Conejos County. Other bordering counties: Rio Arriba County, New Mexico, Taos County, New Mexico.

What it means for your home

About 1 in 3 results in Conejos 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: 75. 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