Short-term kit
Air Chek Short-Term radon test kit you hang, lab fee included
- Lab fee included
In home: 72 to 168 hours
Locations and reports
Radon Levels in Conejos County, Colorado
EPA puts Conejos County in Zone 2, its middle radon zone, and only 4 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
77.1%
Taos County
- Taos
- 77.1%
- Alamosa
- 26.6%
4 of 6 neighbours have 30+ tests, 2008 to 2017
Nearest county
37.5%
Rio Grande County, 28 miles
- Rio Grande
- 37.5%
- Colorado
- 47.0%
Share at 4+ pCi/L, 216 tests, 2008 to 2017
Ground above low
100.0%
Level with Colorado
- Conejos
- 100.0%
- Colorado
- 100.0%
Share of land USGS rates moderate or high potential
Tests reported
28
Too few for a share
- Conejos
- 28
- Needed
- 30
2021
EPA radon zone
Zone 2
Moderate potential
- 1
- Zone 2
- 3
1 highest, 3 lowest
EPA predicts 2 to 4 pCi/L indoors
Read a result for Conejos 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
Conejos County, At a glance
Conejos County at a glance
Predicted: EPA radon zone
EPA Zone 2: moderate predicted potential
Conejos County is a
USGS geologic potential: Moderate across 95% of the county's area
Predicted: EPA Map of Radon Zones
Measured: tests reported to CDC
Radon tests reported for Conejos County, 2023
| Year | Share of reported tests at or above 4 pCi/L |
|---|---|
| 2014 | 50.0% |
| 2015 | 50.0% |
| 2016 | 0.0% |
| 2017 | 33.3% |
| 2019 | 0.0% |
| 2020 | 0.0% |
| 2021 | 50.0% |
| 2022 | 20.0% |
| 2023 | 100.0% |
2023: 100.0%. 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 4 tests were reported to CDC for Conejos 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).
Conejos County, Compared
Conejos County radon figures, compared
Calculated by Radon411CDC's largest figure for Conejos County rests on 28 tests in 2021, 14 of them at or above 4 pCi/L, so each test moves its share by 3.6 points and no rank or comparison is drawn from it. Results reached as high as 172.0 pCi/L, with a middle value of 3.5 pCi/L.
Of the counties bordering it, 4 have a figure over the 2008 to 2017 laboratory totals: Taos County, NM reported the largest share at or above 4 pCi/L, 77.1%, and Alamosa County the smallest, 26.6%, with Rio Grande County at 37.5% and Archuleta County at 31.2% between. Farther out, Huerfano County (75 miles away) at 53.7%, Custer County (77 miles away) at 54.8% and La Plata County (91 miles away) at 46.0% 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 Conejos County in Zone 2, its middle label: a predicted county average between 2 and 4 pCi/L. USGS geology rates 95% of the county's land moderate radon potential.
Pooled shares: Radon411's sum of CDC's county counts for one period.
Conejos County, State data
Colorado's own radon test data
MeasuredWhat Colorado's own agencies publish about radon tests in Conejos 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 Conejos 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
33.3%
25 of 75 tests
Median result
1.7 pCi/L
Highest result
172.0 pCi/L
Tests behind these figures
75 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.
Conejos County, Geology
The ground under Conejos County
PredictedMost of the ground under Conejos County is one class on USGS's geologic map: 95.3% of its land is moderate radon potential, with 4.7% high. 95.3% of it lies in the area the map calls San Juan Volcanic field, to which USGS gives a radon index of 11, in the moderate band (9 to 11).
| Area | The rock, in USGS's words | Potential | Radon index | Share of land |
|---|---|---|---|---|
| San Juan Volcanic field | Volcanic rocks, rhyolite, tuff, basalt | Moderate | 11 | 95.3% |
| Jemez Mountains | Tertiary volcanic rocks. | High | 12 | 4.6% |
Names, descriptions and indexes: U.S. Geological Survey, Geologic Radon Potential Map (2025). Shares: Radon411, from the map cut to the boundary.
Conejos County beside the ground around it
Colorado as a whole has more high-potential ground than Conejos County: 74.8% of its land, against 4.7% here. Of the 6 counties that border it, 4 have more high-potential ground, Taos County, NM the most at 91.9%.
The map rates the ground, not the air in any home.
Local help
Conejos County, Local resources
Radon testing and mitigation in Conejos 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
Conejos County, Questions
Questions about radon in Conejos County
Are radon levels high in Conejos County?
In 2023, 100.0% of the radon tests reported to CDC for Conejos County, Colorado were at or above 4 pCi/L, and the median reported pre-mitigation result was 10.2 pCi/L. Of the counties bordering it, 4 have a figure over the 2008 to 2017 laboratory totals: Taos County, NM reported the largest share at or above 4 pCi/L, 77.1%, and Alamosa County the smallest, 26.6%, with Rio Grande County at 37.5% and Archuleta County at 31.2% between.
Which counties border Conejos County?
Conejos County borders 6 counties: Rio Grande County, CO, Alamosa County, CO, Costilla County, CO, Archuleta County, CO, Taos County, NM and Rio Arriba County, NM.
Products
Conejos County, Products
Testing a home in Conejos County
No CDC figure names Conejos County; the nearest county with one, Rio Grande County (28 miles away), reported 37.5% 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 2 a short-term kit (2 to 90 days) is the quick first check in Conejos County; a long-term test tells the year-round average.
Test kits and monitors3
See every kit and monitor
Long-term kit
RL116 long-term radon test kit
- Lab fee extra
Method: Alpha track
In home: 90 days to 12 months
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
- See every kit and monitor Test kits and monitors
Test kits and monitors: 1 of 3
Explore
Conejos County, Bordering counties
Counties bordering Conejos County
Calculated by Radon411- Radon levels in Taos County, NMEPA zone 1
77.1%at or above 4 pCi/L
Median 8.5 pCi/L · 83 tests
- Radon levels in Rio Arriba County, NMEPA zone 1
50.0%at or above 4 pCi/L
Median 3.5 pCi/L · 14 tests
- Radon levels in Rio Grande County, COEPA zone 2
37.5%at or above 4 pCi/L
Median 3.0 pCi/L · 216 tests
- Radon levels in Costilla County, COEPA zone 2
36.4%at or above 4 pCi/L
Median 3.0 pCi/L · 11 tests
- Radon levels in Archuleta County, COEPA zone 2
31.2%at or above 4 pCi/L
Median 2.3 pCi/L · 600 tests
- Radon levels in Alamosa County, COEPA zone 2
26.6%at or above 4 pCi/L
Median 2.1 pCi/L · 79 tests
Conejos County, Cities and towns
Cities and towns in Conejos County
The Census Bureau estimates 7,529 residents in Conejos County for July 1, 2025, 72 more than in 2020 (+1.0%). Spread over its land, that is 5.8 people to the square mile. No town dominates: Manassa, the largest, has 958 residents, 12.7% of the total. Together its 5 incorporated places hold 46.3% of those residents; the other 53.7% live outside any of them. CDC's 28 reported tests for 2021 work out to 3.7 per 1,000 residents (2025 estimate), close to Colorado's 4.5.
From Manassa to Romeo, CDC publishes no figure by town: each reads Conejos County's.
| Place | Residents | Since 2020 | Share of residents |
|---|---|---|---|
| Manassa | 958 | +1.1% | 12.7% |
| Sanford | 897 | +1.7% | 11.9% |
| La Jara | 708 | −2.3% | 9.4% |
| Antonito | 615 | −4.1% | 8.2% |
| Romeo | 309 | +3.0% | 4.1% |
5 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).
Conejos County, Homes
Homes in Conejos County
Conejos County is a place of houses on their own lots: 77% of its 4,058 homes are detached single-family houses, against 62% across Colorado. The homes are older than Colorado's as a whole: half were built before 1978 (1987 for Colorado), and 32% date from before 1960. 75% 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 | Conejos County | Colorado |
|---|---|---|
| Housing units | 4,058 | 2,545,124 |
| Detached houses | 77% | 62% |
| In buildings of 5 or more | 2% | 22% |
| Mobile homes | 18% | 4% |
| Built before 1960 | 32% | 16% |
| Built since 2000 | 16% | 31% |
| Middle year built | 1978 | 1987 |
| Owner-occupied | 75% | 66% |
Census Bureau, American Community Survey, 2019 to 2023: estimates from a sample of homes, looser for a small place. Shares by Radon411.