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 Dolores County, Colorado
EPA puts Dolores County in Zone 1, its highest radon zone, and only 2 radon tests from it are on file with CDC (2023). Homes with elevated levels occur in all three zones, so only a test measures yours.
Data checked By Radon411Methodology
Highest bordering
46.0%
La Plata County
- La Plata
- 46.0%
- Montezuma
- 37.6%
2 of 5 neighbours have 30+ tests, 2008 to 2017
Nearest county
37.6%
Montezuma County, 29 miles
- Montezuma
- 37.6%
- Colorado
- 47.0%
Share at 4+ pCi/L, 170 tests, 2008 to 2017
Ground above low
100.0%
Level with Colorado
- Dolores
- 100.0%
- Colorado
- 100.0%
Share of land USGS rates moderate or high potential
Tests reported
17
Too few for a share
- Dolores
- 17
- Needed
- 30
2020
EPA radon zone
Zone 1
Highest potential
- Zone 1
- 2
- 3
1 highest, 3 lowest
EPA predicts over 4 pCi/L indoors
Read a result for Dolores County
Starts at EPA's action level
EPA’s own thresholds; the figures are the area’s, never this home’s.
EPA’s reading of 4.0 pCi/L
At or above 4 pCi/L
- Under 20 to 1.9 pCi/L
- 2 to 4consider a fix
- 4 and aboveEPA says fix it
This result is at or above 4 pCi/L. EPA recommends fixing a home when the radon level is 4 pCi/L or higher.
The data
Dolores County, At a glance
Dolores County at a glance
Predicted: EPA radon zone
EPA Zone 1: highest predicted potential
EPA puts all of Dolores County in
USGS geologic potential: High across 93% of the county's area
Predicted: EPA Map of Radon Zones
Measured: tests reported to CDC
Radon tests reported for Dolores County, 2023
| Year | Share of reported tests at or above 4 pCi/L |
|---|---|
| 2014 | 100.0% |
| 2017 | 100.0% |
| 2018 | 0.0% |
| 2019 | 0.0% |
| 2020 | 58.8% |
| 2021 | 66.7% |
| 2022 | 33.3% |
| 2023 | 0.0% |
2023: 0.0%. Across these years the share ran from 0.0% to 100.0%. Each column counts radon tests reported to CDC that year, not homes.
What these figures count
Only 2 tests were reported to CDC for Dolores County over 2023, and tests are often run on homes being sold or already suspected of a problem: so few describe neither the county nor this house.
Measured: CDC tracking data. Figure above: 2023. Measured data period: 2005 to 2023 (every CDC figure on file).
Dolores County, Compared
Dolores County radon figures, compared
Calculated by Radon411CDC's largest figure for Dolores County rests on 17 tests in 2020, 10 of them at or above 4 pCi/L, so each test moves its share by 5.9 points and no rank or comparison is drawn from it. Results reached as high as 80.6 pCi/L, with a middle value of 4.5 pCi/L.
Of the counties bordering it, 2 have a figure over the 2008 to 2017 laboratory totals: La Plata County reported the largest share at or above 4 pCi/L, 46.0%, and Montezuma County the smallest, 37.6%. Farther out, Montrose County (47 miles away) at 60.7%, Ouray County (49 miles away) at 53.3% and Delta County (84 miles away) at 55.2% have figures too. Pooled across 63 Colorado counties, 47.0% of reported tests reached that level; across every county in the country with a figure, 35.7%.
Statewide for the same period, Kit Carson County reported the highest share (71.4%) and Alamosa County the lowest (26.6%). EPA's 1993 map puts Dolores County in Zone 1, the map's highest label: a predicted county average above 4 pCi/L. USGS geology rates 93% of the county's land high radon potential.
Pooled shares: Radon411's sum of CDC's county counts for one period.
Dolores County, State data
Colorado's own radon test data
MeasuredWhat Colorado's own agencies publish about radon tests in Dolores 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 Dolores 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
46.2%
18 of 39 tests
Median result
3.8 pCi/L
Highest result
80.6 pCi/L
Tests behind these figures
39 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.
Dolores County, Geology
The ground under Dolores County
PredictedMost of the ground under Dolores County is one class on USGS's geologic map: 93.1% of its land is high radon potential, with 6.9% moderate. The map puts 93.1% of Dolores County in the area it calls Uravan Belt and 6.9% in San Juan Basin. 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 |
|---|---|---|---|---|
| Uravan Belt | Uranium-bearing Cretaceous and Jurassic sedimentary rocks of the Uravan mineral belt. | High | 13 | 93.1% |
| San Juan Basin | Mesozoic marine and non-marine sedimentary rocks including sandstone, siltstone, shale, minor limestone. | Moderate | 11 | 6.9% |
Names, descriptions and indexes: U.S. Geological Survey, Geologic Radon Potential Map (2025). Shares: Radon411, from the map cut to the boundary.
Dolores County beside the ground around it
Dolores County has more high-potential ground than Colorado as a whole: 93.1% of its land against 74.8%. Of the 5 counties that border it, 1 has more high-potential ground, San Miguel County the most at 96.5%.
The map rates the ground, not the air in any home.
Local help
Dolores County, Local resources
Radon testing and mitigation in Dolores 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
Dolores County, Questions
Questions about radon in Dolores County
Are radon levels high in Dolores County?
In 2023, 0.0% of the radon tests reported to CDC for Dolores County, Colorado were at or above 4 pCi/L, and the median reported pre-mitigation result was 0.5 pCi/L. Of the counties bordering it, 2 have a figure over the 2008 to 2017 laboratory totals: La Plata County reported the largest share at or above 4 pCi/L, 46.0%, and Montezuma County the smallest, 37.6%.
Which counties border Dolores County?
Dolores County borders 5 counties: San Miguel County, CO, Montezuma County, CO, La Plata County, CO, San Juan County, CO and San Juan County, UT.
Products
Dolores County, Products
Testing a home in Dolores County
No CDC figure names Dolores County; the nearest county with one, Montezuma County (29 miles away), reported 37.6% of its tests at or above 4 pCi/L over the 2008 to 2017 laboratory totals, the only reading nearby until a test of this home. In Zone 1 the year-round level in Dolores 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
Monitor
RadonScan USB-powered radon monitor with a color screen
- C-NRPP 2024/25: Not included
- Plug-in
- Alarm
- Screen
First reading: Within 5 minutes
Short-term kitKidde
442020 short-term charcoal radon test kit
- Lab fee included
Method: Charcoal
In home: 3 days
- See every kit and monitor Test kits and monitors
Test kits and monitors: 1 of 3
Dolores County is in EPA Zone 1, the highest predicted radon potential. Best radon monitors for Zone 1 counties like Dolores County
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Dolores County, Bordering counties
Counties bordering Dolores County
Calculated by Radon411- Radon levels in San Juan County, UTEPA zone 2
66.7%at or above 4 pCi/L
Median 5.1 pCi/L · 15 tests
- Radon levels in San Miguel County, COEPA zone 1
52.0%at or above 4 pCi/L
Median 4.5 pCi/L · 25 tests
- Radon levels in La Plata County, COEPA zone 1
46.0%at or above 4 pCi/L
Median 3.6 pCi/L · 1,612 tests
- Radon levels in Montezuma County, COEPA zone 1
37.6%at or above 4 pCi/L
Median 3.1 pCi/L · 170 tests
- Radon levels in San Juan County, COEPA zone 2
No CDC figure for 2008 to 2017; its page reads it against its own neighbours.
Dolores County, Cities and towns
Cities and towns in Dolores County
Dolores County is growing: the Census Bureau puts it at 2,466 residents on July 1, 2025, up 5.8% from 2,331 in 2020. Spread over its land, that is 2.3 people to the square mile. Its largest town, Dove Creek, has 664 residents, 26.9% of the total. Together its 2 incorporated places hold 41.0% of those residents; the other 59.0% live outside any of them. Testing is reported here more often than across the state: CDC's 17 reported tests for 2020 come to 6.9 for every 1,000 residents (2025 estimate), against 4.1 for Colorado.
From Dove Creek to Rico, CDC publishes no figure by town: each reads Dolores County's.
| Place | Residents | Since 2020 | Share of residents |
|---|---|---|---|
| Dove Creek | 664 | +4.2% | 26.9% |
| Rico | 347 | +18.4% | 14.1% |
2 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).
Dolores County, Homes
Homes in Dolores County
Of Dolores County's 1,640 homes, 73% are detached houses, against 62% across Colorado; 21% are mobile homes. The homes are older than Colorado's as a whole: half were built before 1978 (1987 for Colorado), and 32% date from before 1960. Owners live in 84% of the occupied homes (Colorado: 66%), so for most households a test and a fix are their own to order.
| Homes | Dolores County | Colorado |
|---|---|---|
| Housing units | 1,640 | 2,545,124 |
| Detached houses | 73% | 62% |
| In buildings of 5 or more | 4% | 22% |
| Mobile homes | 21% | 4% |
| Built before 1960 | 32% | 16% |
| Built since 2000 | 19% | 31% |
| Middle year built | 1978 | 1987 |
| Owner-occupied | 84% | 66% |
Census Bureau, American Community Survey, 2019 to 2023: estimates from a sample of homes, looser for a small place. Shares by Radon411.