Colorado · CDPHE dataset

Colorado Radon Levels by County (CDPHE Data, 2005–2024)

Across all 64 Colorado counties, 46.9% of pre-mitigation home radon tests came back at or above the EPA action level of 4 pCi/L, based on 214,362 tests collected by the Colorado Department of Public Health and Environment between 2005 and 2024.

The data is sliced to county level — no individual addresses, no personally identifying information. EPA recommends mitigation at 4 pCi/L. Counties with elevated medians and large test counts warrant testing in real-estate transactions and seasonal retesting in occupied homes.

Statewide risk map

One-page handout summarizing all 64 counties — preview below, full PDF in the Downloads section.

Preview of the Colorado Radon Risk Map summarizing all 64 counties

Map preview · interactive choropleth coming in a later release

Every Colorado county, sortable

Click any column header to sort. Click again to flip direction. Click a county name to see its detail page.

San Juan8971.9%5.761
Hinsdale4868.8%6.75273.1
Kiowa1566.7%4.7251
LincolnFR5066.0%4.725.2
MorganFR31064.2%5.1236
Pueblo5,73763.8%5.8279
Costilla2161.9%5.621
Jackson4660.9%5.0522.2
WashingtonFR4860.4%4.747.3
Kit CarsonFR10558.1%4.520.8
Chaffee1,47057.6%4.9250
Otero14657.5%4.6114
YumaFR8257.3%4.317.4
Cheyennelow dataFR757.1%6.114.3
Montrose2,35756.4%4.6361.7
Gilpin54655.9%4.85773.9
Teller2,60655.0%4.7957.4
LarimerFR18,51254.9%4.61146.8
Delta76054.9%4.5209
Lake36954.5%4.4214
Fremont75153.8%4.6110
ElbertFR91953.0%4.1240
Ouray27252.6%4.1230
Moffat25151.8%4.1180
Routt2,56051.2%4.1276
Rio Blanco17950.8%4143.6
JeffersonFR27,55450.8%4510.7
WeldFR10,16549.2%3.9275
ArapahoeFR19,35648.4%3.8369.6
Park97248.1%3.7338.1
Pitkin2,49447.2%3.6307.6
DouglasFR15,07947.1%3.6274
Dolores3447.1%3.880.6
AdamsFR11,21246.8%3.6279
Summit3,53346.4%3.4379.3
PhillipsFR5046.0%3.717
Prowers18245.6%3.55239
Gunnison1,26445.3%3.4263
Crowley2045.0%3.59.6
Eagle3,58945.0%3.5235
Custer40944.7%3.2217.6
BroomfieldFR4,15944.3%3.2205
GrandFR92744.1%3.3212
BoulderFR17,99243.8%3.3384.6
La Plata3,15843.5%3.4315.1
Mineral7643.4%3.1592
Garfield2,98843.3%3.3276
Baca5442.6%2.9208
San Miguel21842.2%398.2
Las Animas92341.0%3.159.5
DenverFR19,44639.6%3.1310.1
El Paso22,27239.5%3278
Clear Creek68836.8%2.3240
LoganFR10536.2%315
Rio Grande38936.0%2.7336.6
Conejos7133.8%1.7172
Archuleta95533.6%2.5209
Mesa3,82033.6%2.7301
Huerfano67529.3%2113.7
Montezuma71027.5%2.4107.6
Saguache18525.9%1.574.8
Alamosa15425.3%2116
SedgwickFR8422.6%1.811.7
Bent14414.6%0.412.8

Downloads

Free to redistribute under CC0. Attribution to CDPHE appreciated but not required.

Download the dataset

CSV

County-level CSV

64 rows · 8 columns · UTF-8

Download · 2.9 KB

PDF

Colorado Radon Risk Map

One-page, print-ready handout

Download · 468 KB

How to cite this dataset

Colorado Department of Public Health and Environment. Colorado Pre-Mitigation Indoor Radon Test Results, 2005–2024. Compiled and republished by Colorado Radon Check, 2026. https://coloradoradoncheck.com/colorado/data/
Coverage
All 64 Colorado counties · 2005–2024 · pre-mitigation tests only
License
Creative Commons Zero (CC0) · public-domain dedication
Variables measured
Number of tests · % at or above 4 pCi/L · median pre-mitigation result · maximum recorded result

Free download

Get the one-page Colorado Radon Risk Map

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Question about a specific county or how to read these numbers? Call us at (866) 398-9858.