Long-term kit
RL416 long-term radon test kit, lab fee included
- Lab fee included
Method: Alpha track
In home: 90 days to 12 months
Locations and reports
Radon Levels in Phillips County, Colorado
EPA puts Phillips County in Zone 1, its highest radon zone, and only 7 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
Share at 4+ pCi/L
40.7%
6.3 pts below CO
- Phillips
- 40.7%
- Colorado
- 47.0%
54 tests, 2008 to 2017
Median result
3.5pCi/L
Below action level
- Phillips
- 3.5 pCi/L
- EPA
- 4.0 pCi/L
Midpoint of the tests, 2008 to 2017
Tests reported
54
44th of 50 by tests
- Phillips
- 54
- Jefferson
- 11,723
Reported to CDC before any fix, 2008 to 2017
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
43 of 50
Lowest quarter
- Phillips
- 40.7%
- Kit Carson
- 71.4%
By share, of 50 with 30+ tests
Read a result for Phillips County
Starts at Phillips County's median, 3.5 pCi/L
EPA’s own thresholds; the figures are the area’s, never this home’s.
EPA’s reading of 3.5 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. Phillips County's median reported result, 2008 to 2017.
The data
Phillips County, At a glance
Phillips County at a glance
Predicted: EPA radon zone
EPA Zone 1: highest predicted potential
EPA puts all of Phillips County in
USGS geologic potential: High across 88% of the county's area
Predicted: EPA Map of Radon Zones
Measured: tests reported to CDC
Radon tests reported for Phillips County, 2023
| Year | Share of reported tests at or above 4 pCi/L |
|---|---|
| 2014 | 50.0% |
| 2015 | 100.0% |
| 2016 | 0.0% |
| 2017 | 0.0% |
| 2018 | 44.4% |
| 2019 | 100.0% |
| 2020 | 0.0% |
| 2021 | 0.0% |
| 2022 | 25.0% |
| 2023 | 28.6% |
2023: 28.6%. 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 7 tests were reported to CDC for Phillips 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).
Phillips County, Compared
Phillips County radon figures, compared
Calculated by Radon411In Phillips County, about 4 in 10 reported tests over the 2008 to 2017 laboratory totals (22 of 54) were at or above EPA's action level. Against the national pool of 35.7%, the gap is 5.0 points higher. Across 63 Colorado counties pooled together, 47.0% of tests reached that level, so Phillips County runs 6.3 points below its state.
The newest figure, in 2023, counts only 7 tests (28.6% at or above 4 pCi/L), too few to compare, so this reading uses the 54-test figure.
Of 4 neighbours with a figure, all 4 reported a larger share at or above 4 pCi/L; the spread is 50.0% (Perkins County, NE) to 68.2% (Chase County, NE). By share, Phillips County is 43rd of 50 Colorado counties with 30 or more tests for the same period.
Half the tests came in under 3.5 pCi/L and half over it; the single highest reached 26.4 pCi/L. Below the action level, 14 tests (25.9%) came in under 2 pCi/L, against 31.4% statewide, and 18 tests (33.3%) fell between 2 and 4, against 21.5% statewide.
Zone 1 on EPA's map (predicted average above 4 pCi/L) and a 40.7% share point the same way here. USGS geology rates 88% of the county's land high radon potential.
The busiest year on file was 2018, with 9 tests reported; the quietest, 2019, had 1.
Pooled shares: Radon411's sum of CDC's county counts for one period.
Phillips County, State data
Colorado's own radon test data
MeasuredWhat Colorado's own agencies publish about radon tests in Phillips 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 Phillips 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%
24 of 56 tests
Median result
3.6 pCi/L
Highest result
17.0 pCi/L
Tests behind these figures
56 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.
Phillips County, Geology
The ground under Phillips County
PredictedMost of the ground under Phillips County is one class on USGS's geologic map: 88.1% of its land is high radon potential, with 11.9% moderate. The map puts 88.1% of Phillips County in the area it calls Ogallala Formation and 11.9% in Tertiary Rocks. USGS gives the first a radon index of 12, 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 |
|---|---|---|---|---|
| Ogallala Formation | Tertiary sandstone, in part covered by windblown eolian sand and loess deposits. | High | 12 | 88.1% |
| Tertiary Rocks | Tertiary sandstone, siltstone, and volcanic ash. | Moderate | 11 | 11.9% |
Names, descriptions and indexes: U.S. Geological Survey, Geologic Radon Potential Map (2025). Shares: Radon411, from the map cut to the boundary.
Phillips County beside the ground around it
Phillips County has more high-potential ground than Colorado as a whole: 88.1% of its land against 74.8%. Of the 5 counties that border it, none has as large a share of high-potential ground; Sedgwick County comes nearest at 78.5%.
The map rates the ground, not the air in any home.
Local help
Phillips County, Local resources
Radon testing and mitigation in Phillips 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
Phillips County, Questions
Questions about radon in Phillips County
Are radon levels high in Phillips County?
In 2023, 28.6% of the radon tests reported to CDC for Phillips County, Colorado were at or above 4 pCi/L, and the median reported pre-mitigation result was 3.5 pCi/L. Of 50 Colorado counties with 30 or more tests for the same period, 42 reported a higher share; pooled, the state comes to 47.0%.
Which counties border Phillips County?
Phillips County borders 5 counties: Sedgwick County, CO, Yuma County, CO, Chase County, NE, Logan County, CO and Perkins County, NE.
Products
Phillips County, Products
Testing a home in Phillips County
In Phillips County, 40.7% of 54 tests reported to CDC over the 2008 to 2017 laboratory totals reached 4 pCi/L, against 47.0% pooled across Colorado. In Zone 1 the year-round level in Phillips 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
XR0A-SR battery digital radon detector with a screen
- C-NRPP 2024/25: Not included
- Battery
- Screen
Method: Alpha spectrometry
First reading: Within 24 hours
Short-term kit
RA100 short-term liquid scintillation radon test kit
- Lab fee extra
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
Phillips County is in EPA Zone 1, the highest predicted radon potential. Best radon monitors for Zone 1 counties like Phillips County
Explore
Phillips County, Bordering counties
Counties bordering Phillips County
Calculated by Radon411- Radon levels in Chase County, NEEPA zone 2
68.2%at or above 4 pCi/L
Median 6.5 pCi/L · 44 tests · 27.5 points above Phillips County
- Radon levels in Logan County, COEPA zone 1
58.8%at or above 4 pCi/L
Median 4.8 pCi/L · 80 tests · 18.1 points above Phillips County
- Radon levels in Yuma County, COEPA zone 1
57.1%at or above 4 pCi/L
Median 4.0 pCi/L · 35 tests · 16.4 points above Phillips County
- Radon levels in Perkins County, NEEPA zone 2
50.0%at or above 4 pCi/L
Median 4.0 pCi/L · 40 tests · 9.3 points above Phillips County
- Radon levels in Sedgwick County, COEPA zone 1
44.4%at or above 4 pCi/L
Median 3.8 pCi/L · 18 tests · 3.7 points above Phillips County
Phillips County, Cities and towns
Cities and towns in Phillips County
About 4,420 people live in Phillips County by the Census Bureau's estimate for July 1, 2025, 108 fewer than in 2020 (−2.4%). Spread over its land, that is 6.4 people to the square mile. Holyoke alone is home to 2,264 of them, 51.2% of the total. Together its 3 incorporated places hold 73.8% of those residents; the other 26.2% live outside any of them. CDC's 54 reported tests for 2008 to 2017 work out to 12.2 per 1,000 residents (2025 estimate), close to Colorado's 16.0.
From Holyoke to Paoli, CDC publishes no figure by town: each reads Phillips County's.
| Place | Residents | Since 2020 | Share of residents |
|---|---|---|---|
| Holyoke | 2,264 | −3.5% | 51.2% |
| Haxtun | 951 | −3.1% | 21.5% |
| Paoli | 48 | −4.0% | 1.1% |
3 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).
Phillips County, Homes
Homes in Phillips County
Phillips County is a place of houses on their own lots: 86% of its 2,085 homes are detached single-family houses, against 62% across Colorado. The homes are older than Colorado's as a whole: half were built before 1968 (1987 for Colorado), and 43% 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 | Phillips County | Colorado |
|---|---|---|
| Housing units | 2,085 | 2,545,124 |
| Detached houses | 86% | 62% |
| In buildings of 5 or more | 3% | 22% |
| Mobile homes | 6% | 4% |
| Built before 1960 | 43% | 16% |
| Built since 2000 | 17% | 31% |
| Middle year built | 1968 | 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.