Long-term kit
RL116 long-term radon test kit
- Lab fee extra
Method: Alpha track
In home: 90 days to 12 months
Locations and reports
Radon Levels in Garfield County, Colorado
EPA puts Garfield County in Zone 1, its highest radon zone, and 39.3% of its 224 reported radon tests (2023) were at or above 4 pCi/L. Homes with elevated levels occur in all three zones, so only a test measures yours.
Data checked By Radon411Methodology
Share at 4+ pCi/L
39.3%
0.4 pts above CO
- Garfield
- 39.3%
- Colorado
- 38.9%
224 tests, 2023
Median result
2.9pCi/L
Below action level
- Garfield
- 2.9 pCi/L
- EPA
- 4.0 pCi/L
Midpoint of the tests, 2023
Tests reported
224
15th of 38 by tests
- Garfield
- 224
- Jefferson
- 3,068
Reported to CDC before any fix, 2023
EPA radon zone
Zone 1
Highest potential
- Zone 1
- 2
- 3
1 highest, 3 lowest
EPA predicts over 4 pCi/L indoors
Rank in Colorado
20 of 38
Middle half
- Garfield
- 39.3%
- Park
- 57.5%
By share, of 38 with 30+ tests
Read a result for Garfield County
Starts at Garfield County's median, 2.9 pCi/L
EPA’s own thresholds; the figures are the area’s, never this home’s.
EPA’s reading of 2.9 pCi/L
Between 2 and 4 pCi/L
- Under 20 to 1.9 pCi/L
- 2 to 4consider a fix
- 4 and aboveEPA says fix it
This result is between 2 and 4 pCi/L. EPA recommends considering a fix when the level is between 2 and 4 pCi/L. Garfield County's median reported result, 2023.
The data
Garfield County, At a glance
Garfield County at a glance
Predicted: EPA radon zone
EPA Zone 1: highest predicted potential
EPA puts all of Garfield County in
USGS geologic potential: High across 58% of the county's area
Predicted: EPA Map of Radon Zones
Measured: tests reported to CDC
Radon tests reported for Garfield County, 2023
| Year | Share of reported tests at or above 4 pCi/L |
|---|---|
| 2014 | 44.1% |
| 2015 | 45.6% |
| 2016 | 35.4% |
| 2017 | 43.3% |
| 2018 | 38.9% |
| 2019 | 43.6% |
| 2020 | 41.7% |
| 2021 | 55.4% |
| 2022 | 38.8% |
| 2023 | 39.3% |
2023: 39.3%. Across these years the share ran from 35.4% to 55.4%. Each column counts radon tests reported to CDC that year, not homes.
What these figures count
These are the 224 tests reported to CDC for Garfield County over 2023, many from homes being sold or already suspected of a problem: they describe the county's reported tests, not this house.
Measured: CDC tracking data. Figure above: 2023. Measured data period: 2005 to 2023 (every CDC figure on file).
Garfield County, Compared
Garfield County radon figures, compared
Calculated by Radon411In Garfield County, about 4 in 10 reported tests in 2023 (88 of 224) were at or above EPA's action level. Against the national pool of 33.4%, the gap is 5.9 points higher. Across 61 Colorado counties pooled together, 38.9% of tests reached that level, so Garfield County runs 0.4 points above its state.
Of 6 neighbours with a figure, 3 reported a larger share at or above 4 pCi/L and 3 a smaller one; the spread is 18.9% (Mesa County) to 51.0% (Uintah County, UT). By share, Garfield County is 20th of 38 Colorado counties with 30 or more tests for the same period.
Year by year, 2014 opened at 44.1% and 2023 closed at 39.3% (down 4.8 points), with 2021 the high at 55.4%. Half the tests came in under 2.9 pCi/L and half over it; the single highest reached 51.6 pCi/L. Below the action level, 71 tests (31.7%) came in under 2 pCi/L, against 39.2% statewide, and 65 tests (29.0%) fell between 2 and 4, against 22.0% statewide.
Zone 1 on EPA's map (predicted average above 4 pCi/L) and a 39.3% share point the same way here. USGS geology rates 58% of the county's land high radon potential. CDC also counts 16 tests taken after mitigation in Garfield County for the same period: tests in homes where a fix was already in.
The busiest year on file was 2018, with 388 tests reported; the quietest, 2021, had 148.
Garfield CountyColorado, pooled
| Year | Tests | Garfield County, at or above 4 pCi/L | Colorado, pooled |
|---|---|---|---|
| 2014 | 161 | 44.1% | 46.5% |
| 2015 | 182 | 45.6% | 47.2% |
| 2016 | 206 | 35.4% | 38.5% |
| 2017 | 233 | 43.3% | 41.0% |
| 2018 | 388 | 38.9% | 44.2% |
| 2019 | 342 | 43.6% | 44.1% |
| 2020 | 206 | 41.7% | 41.9% |
| 2021 | 148 | 55.4% | 47.3% |
| 2022 | 214 | 38.8% | 38.6% |
| 2023 | 224 | 39.3% | 38.9% |
Pooled shares: Radon411's sum of CDC's county counts for one period.
Garfield County, State data
Colorado's own radon test data
MeasuredWhat Colorado's own agencies publish about radon tests in Garfield County, with their period. These are not CDC's figures and are never added to them.
MeasuredState figures, not CDC's
What Colorado CDPHE reports for Garfield County
Radon data (county results): radon test results received from radon testing labs, primarily short-term household tests taken by the homeowner. Period: 2005-2025.
Share over 4 pCi/L
42.9%
1,390 of 3,243 tests
Median result
3.3 pCi/L
Highest result
276.0 pCi/L
Tests behind these figures
3,243 tests
- CDPHE says these data do not give actual radon levels in homes that have not been tested.
- When possible, only tests conducted before a mitigation system was installed are used.
- Some counties have very small numbers of test results, and their summaries may be less representative.
- These figures describe tests reported to Colorado CDPHE in this area. They count a different set of tests than CDC's figures and are not a reading of any one home.
Measured: Colorado CDPHE data, 2005-2025.
Garfield County, Geology
The ground under Garfield County
PredictedUSGS's geologic map splits Garfield County: 57.5% of its land is high radon potential and 42.5% moderate. The map puts 52.8% of Garfield County in the area it calls Paradox Basin and 42.5% in Western Slope, with one smaller area beside them. USGS gives the first a radon index of 13, in the high band (12 to 17), and the second 11, in the moderate band (9 to 11).
| Area | The rock, in USGS's words | Potential | Radon index | Share of land |
|---|---|---|---|---|
| Paradox Basin | Tertiary sandstone, siltstone and shale. | High | 13 | 52.8% |
| Western Slope | Paleozoic and Mesozoic sandstone, siltstone, shale, basalt. | Moderate | 11 | 42.5% |
| Mancos Shale Lowlands | Marine shales (Mancos Shale) and Tertiary sandstones. | High | 13 | 4.8% |
Names, descriptions and indexes: U.S. Geological Survey, Geologic Radon Potential Map (2025). Shares: Radon411, from the map cut to the boundary.
Garfield County beside the ground around it
Colorado as a whole has more high-potential ground than Garfield County: 74.8% of its land, against 57.5% here. Of the 7 counties that border it, 4 have more high-potential ground, Mesa County the most at 99.5%.
The map rates the ground, not the air in any home.
Local help
Garfield County, Local resources
Radon testing and mitigation in Garfield County
- Colorado's radon programColorado Department of Public Health and EnvironmentColorado's radon program licenses or certifies radon professionals, offers free or discounted test kits and states the rule for disclosing radon when a home is sold, and answers questions about testing and mitigation in Colorado.Visit the program’s page(opens in a new tab)
- Free and low-cost kitsThe program says:
Order a discounted radon test kit
- Compare kits
- Professionals in Colorado25 professionals are listed in Colorado.
What Colorado's program says
- Licensing of radon professionals
Listed contractors are certified by the National Radon Proficiency Program or the National Radon Safety Board, and must be licensed by the Colorado Department of Regulatory Agencies.
- Disclosure when a home is sold or rented
As of August 7, 2023, landlords in Colorado are required to disclose radon information when a tenant signs a lease agreement.
What it means
Garfield County, Questions
Questions about radon in Garfield County
Are radon levels high in Garfield County?
In 2023, 39.3% of the radon tests reported to CDC for Garfield County, Colorado were at or above 4 pCi/L, and the median reported pre-mitigation result was 2.9 pCi/L. Of 38 Colorado counties with 30 or more tests for the same period, 19 reported a higher share; pooled, the state comes to 38.9%.
Which counties border Garfield County?
Garfield County borders 7 counties: Rio Blanco County, CO, Eagle County, CO, Pitkin County, CO, Routt County, CO, Mesa County, CO, Uintah County, UT and Grand County, UT.
Products
Garfield County, Products
Testing a home in Garfield County
In Garfield County, 39.3% of 224 tests reported to CDC in 2023 reached 4 pCi/L, against 38.9% pooled across Colorado. In Zone 1 the year-round level in Garfield County is the one to know: a long-term test (more than 90 days) or a monitor, with a short-term kit for a first answer.
Test kits and monitors3
See every kit and monitor
MonitorX-Sense
XR0B-SR battery digital radon monitor with an alarm
- C-NRPP 2024/25: Not included
- Battery
- Alarm
- Screen
Method: Alpha spectrometry
First reading: Within 24 hours
Short-term kit
RA400 short-term liquid scintillation radon test kit, lab fee included
- Lab fee included
Method: Liquid scintillation
In home: 48 to 96 hours
- See every kit and monitor Test kits and monitors
Test kits and monitors: 1 of 3
Garfield County is in EPA Zone 1, the highest predicted radon potential. Best radon monitors for Zone 1 counties like Garfield County
Explore
Garfield County, Bordering counties
Counties bordering Garfield County
Calculated by Radon411- Radon levels in Uintah County, UTEPA zone 1
51.0%at or above 4 pCi/L
Median 4.2 pCi/L · 104 tests · 11.7 points above Garfield County
- Radon levels in Eagle County, COEPA zone 2
45.8%at or above 4 pCi/L
Median 3.5 pCi/L · 312 tests · 6.5 points above Garfield County
- Radon levels in Routt County, COEPA zone 2
44.4%at or above 4 pCi/L
Median 3.3 pCi/L · 178 tests · 5.1 points above Garfield County
- Radon levels in Pitkin County, COEPA zone 1
36.6%at or above 4 pCi/L
Median 2.5 pCi/L · 164 tests · 2.7 points below Garfield County
- Radon levels in Grand County, UTEPA zone 1
23.9%at or above 4 pCi/L
Median 1.9 pCi/L · 46 tests · 15.4 points below Garfield County
- Radon levels in Rio Blanco County, COEPA zone 1
20.0%at or above 4 pCi/L
Median 1.9 pCi/L · 15 tests · 19.3 points below Garfield County
- Radon levels in Mesa County, COEPA zone 1
18.9%at or above 4 pCi/L
Median 2.2 pCi/L · 567 tests · 20.4 points below Garfield County
Garfield County, Cities and towns
Cities and towns in Garfield County
The Census Bureau estimates 63,474 residents in Garfield County for July 1, 2025, 1,681 more than in 2020 (+2.7%). That works out to 22 people per square mile of land. No town dominates: Rifle, the largest, has 10,844 residents, 17.1% of the total. Together its 7 incorporated places hold 59.9% of those residents; the other 40.1% live outside any of them. CDC's 224 reported tests for 2023 work out to 3.5 per 1,000 residents (2025 estimate), close to Colorado's 3.6.
From Rifle to Carbonate, CDC publishes no figure by town: each reads Garfield County's.
| Place | Residents | Since 2020 | Share of residents |
|---|---|---|---|
| Rifle | 10,844 | +3.9% | 17.1% |
| Glenwood Springs | 10,395 | +3.9% | 16.4% |
| Carbondale | 6,762 | +4.6% | 10.7% |
| New Castle | 4,896 | −0.4% | 7.7% |
| Silt | 3,743 | +5.3% | 5.9% |
| Parachute | 1,366 | −1.7% | 2.2% |
| Carbonate | 0 | Not published | 0.0% |
7 incorporated places, as listed in the U.S. Census Bureau’s 2020 place reference files. Residents: U.S. Census Bureau population estimates for July 1, 2025 (Vintage 2025).
Garfield County, Homes
Homes in Garfield County
Of Garfield County's 24,640 homes, 60% are detached houses, against 62% across Colorado; 12% are in buildings of five or more homes. Half of its homes were built before 1992, close to Colorado's 1987: 11% date from before 1960 and 34% from 2000 or later. 70% of occupied homes are lived in by their owner (Colorado: 66%); in the rest a tenant can run a test, but a fix is the landlord's to make.
| Homes | Garfield County | Colorado |
|---|---|---|
| Housing units | 24,640 | 2,545,124 |
| Detached houses | 60% | 62% |
| In buildings of 5 or more | 12% | 22% |
| Mobile homes | 12% | 4% |
| Built before 1960 | 11% | 16% |
| Built since 2000 | 34% | 31% |
| Middle year built | 1992 | 1987 |
| Owner-occupied | 70% | 66% |
Census Bureau, American Community Survey, 2019 to 2023: estimates from a sample of homes, looser for a small place. Shares by Radon411.