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Radon Levels in Logan County, Colorado

EPA puts Logan County in Zone 1, its highest radon zone, and only 21 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

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  • Share at 4+ pCi/L

    58.8%

    11.8 pts above CO

    Logan
    58.8%
    Colorado
    47.0%

    80 tests, 2008 to 2017

  • Median result

    4.8pCi/L

    Action level reached

    Logan
    4.8 pCi/L
    EPA
    4.0 pCi/L

    Midpoint of the tests, 2008 to 2017

  • Tests reported

    80

    40th of 50 by tests

    Logan
    80
    Jefferson
    11,723

    Reported to CDC before any fix, 2008 to 2017

  • EPA radon zone

    Zone 1

    Highest potential

    1. Zone 1
    2. 2
    3. 3

    1 highest, 3 lowest

    EPA predicts over 4 pCi/L indoors

  • Rank in Colorado

    13 of 50

    Top quarter

    Logan
    58.8%
    Kit Carson
    71.4%

    By share, of 50 with 30+ tests

Read a result for Logan County

Starts at Logan County's median, 4.8 pCi/L

4.8pCi/L

EPA’s own thresholds; the figures are the area’s, never this home’s.

EPA’s reading of 4.8 pCi/L

At or above 4 pCi/L

  1. Under 20 to 1.9 pCi/L
  2. 2 to 4consider a fix
  3. 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. Logan County's median reported result, 2008 to 2017.

Interpret this readingWhat a fix costs

The data

Logan County, At a glance

Logan County at a glance

Predicted: EPA radon zone

EPA Zone 1: highest predicted potential

EPA puts all of Logan County in and predicts an average indoor of greater than 4 pCi/L (greater than 150 Bq/m³) across the county. That is one forecast for the whole county, not a reading of any address in it; homes above EPA's turn up in all three zones.

USGS geologic potential: High across 59% of the county's area

Predicted: EPA Map of Radon Zones

Measured: tests reported to CDC

Radon tests reported for Logan County, 2023

Share of reported tests at or above 4 pCi/L, by year, Logan County
Share of reported tests at or above 4 pCi/L, by year, Logan County
YearShare of reported tests at or above 4 pCi/L
20140.0%
201555.6%
20160.0%
201757.6%
201860.7%
201933.3%
202041.7%
202160.0%
202237.5%
202323.8%

2023: 23.8%. Across these years the share ran from 0.0% to 60.7%. Each column counts radon tests reported to CDC that year, not homes.

What these figures count

Only 21 tests were reported to CDC for Logan 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).

How to read these figures

Logan County, Compared

Logan County radon figures, compared

Calculated by Radon411

More than half: 58.8% of the 80 radon tests reported to CDC for Logan County over the 2008 to 2017 laboratory totals read at least 4 pCi/L. That places it 13th of 50 Colorado counties with 30 or more tests for the same period. That is 11.8 points above the 47.0% pooled from 63 Colorado counties.

The newest figure, in 2023, counts only 21 tests (23.8% at or above 4 pCi/L), too few to compare, so this reading uses the 80-test figure.

The median result, 4.8 pCi/L, sits above EPA's 4 pCi/L action level, and the top reported result was 25.1 pCi/L. The rest split 17.5% under 2 pCi/L and 23.8% from 2 to 4 (Colorado: 31.4% and 21.5%). Zone 1 on EPA's map (predicted average above 4 pCi/L) and a 58.8% share point the same way here.

2 of its 7 bordering counties with figures ran higher, led by Washington County at 62.8%; Phillips County reported 40.7%. Statewide for the same period, Kit Carson County reported the highest share (71.4%) and Alamosa County the lowest (26.6%).

The busiest year on file was 2017, with 33 tests reported; the quietest, 2014, had 1.

Nationally, every county with a figure for the same period pools to 35.7%; Logan County sits 23.1 points above it. CDC also counts 6 tests taken after mitigation in Logan County for the same period: tests in homes where a fix was already in.

Logan County against Colorado, the United States and nearby counties, 2008 to 2017, laboratory
AreaTestsAt or above 4 pCi/LMedianDifference from Logan County
Logan County8058.8%4.8 pCi/LThis county
Colorado, pooled63 counties, pooled96,36747.0%Not pooled−11.8 points
United States, pooled2,661 counties, pooled2,013,54435.7%Not pooled−23.1 points
Kit Carson Countyhighest in the state4271.4%5.3 pCi/L+12.6 points
Alamosa Countylowest in the state7926.6%2.1 pCi/L−32.2 points
Washington County, COborders it8662.8%4.6 pCi/L+4.0 points
Morgan County, COborders it20859.1%4.9 pCi/L+0.3 points
Yuma County, COborders it3557.1%4.0 pCi/L−1.7 points
Cheyenne County, NEborders it29253.4%4.1 pCi/L−5.4 points
Weld County, COborders it4,37849.7%3.9 pCi/L−9.1 points
Kimball County, NEborders it8144.4%3.6 pCi/L−14.4 points
Sedgwick County, COborders it1844.4%3.8 pCi/L−14.4 points
Phillips County, COborders it5440.7%3.5 pCi/L−18.1 points
Where Logan County's reported results fell, 2008 to 2017, laboratory, beside Colorado and the United States
ResultLogan County testsLogan County shareColorado shareU.S. shareAgainst Colorado
Under 2 pCi/L1417.5%31.4%39.6%−13.9 points
2 to 4 pCi/L1923.8%21.5%24.7%+2.3 points
4 pCi/L and above4758.8%47.0%35.7%+11.8 points
Logan County ranked among the 50 Colorado counties with 30 or more tests, by share at or above 4 pCi/L, 2008 to 2017, laboratory
CountyRankTestsAt or above 4 pCi/LMedian
Chaffee County8 of 5052560.4%5.1 pCi/L
Rio Blanco County9 of 503560.0%4.6 pCi/L
Teller County10 of 501,12159.6%5.2 pCi/L
Bent County11 of 503259.4%4.2 pCi/L
Morgan County12 of 5020859.1%4.9 pCi/L
Logan County13 of 508058.8%4.8 pCi/L
Summit County14 of 5052058.7%5.0 pCi/L
Fremont County15 of 5032258.1%5.2 pCi/L
Otero County16 of 505757.9%4.6 pCi/L
Larimer County17 of 509,32557.9%5.0 pCi/L
Yuma County18 of 503557.1%4.0 pCi/L
Logan County radon tests by year, against Colorado's pooled share
YearTestsAt or above 4 pCi/LMedianHighestColorado, pooledChange from the row before
20232123.8%2.3 pCi/L8.4 pCi/L38.9%−13.7 points
20221637.5%3.1 pCi/L10.2 pCi/L38.6%−22.5 points
2021560.0%6.3 pCi/L8.0 pCi/L47.3%+18.3 points
20201241.7%3.7 pCi/L7.3 pCi/L41.9%+8.4 points
20192133.3%2.9 pCi/L5.6 pCi/L44.1%−27.4 points
20182860.7%4.3 pCi/L10.1 pCi/L44.2%+3.1 points
20173357.6%4.7 pCi/L25.1 pCi/L41.0%+57.6 points
201620.0%2.0 pCi/L2.7 pCi/L38.5%−55.6 points
2015955.6%5.4 pCi/L12.2 pCi/L47.2%+55.6 points
201410.0%3.8 pCi/L3.8 pCi/L46.5%First on file

Pooled shares: Radon411's sum of CDC's county counts for one period.

Logan County, State data

Colorado's own radon test data

Measured

What Colorado's own agencies publish about radon tests in Logan 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 Logan 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

36.8%

46 of 125 tests

Median result

3.0 pCi/L

Highest result

18.8 pCi/L

Tests behind these figures

125 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.

Logan County, Geology

The ground under Logan County

Predicted

USGS's geologic map splits Logan County: 59.3% of its land is high radon potential and 40.7% moderate. The map puts 40.7% of Logan County in the area it calls White River Formation and 38.1% in High Plains, with one smaller area beside them. USGS gives the first a radon index of 11, in the moderate band (9 to 11), and the second 12, in the high band (12 to 17).

USGS's geologic areas under Logan County
AreaThe rock, in USGS's wordsPotentialRadon indexShare of land
White River FormationSiltstone, sandstone, conglomerate, volcanic tuff.Moderate1140.7%
High PlainsQuaternary deposits and Cretaceous marine shales that locally have a high radiometric signature.High1238.1%
Ogallala FormationTertiary sandstone, in part covered by windblown eolian sand and loess deposits.High1221.2%

Names, descriptions and indexes: U.S. Geological Survey, Geologic Radon Potential Map (2025). Shares: Radon411, from the map cut to the boundary.

Logan County beside the ground around it

Colorado as a whole has more high-potential ground than Logan County: 74.8% of its land, against 59.3% here. Of the 8 counties that border it, 5 have more high-potential ground, Morgan County the most at 100%.

Share of land by USGS radon potential: Logan County, the 8 counties bordering it and Colorado
AreaEPA zoneLow potentialModerate potentialHigh potential
Logan CountyZone 1None40.7%59.3%
Cheyenne County, NEZone 2None100%None
Phillips CountyZone 1None11.9%88.1%
Sedgwick CountyZone 1None21.5%78.5%
Kimball County, NEZone 2None100%None
Washington CountyZone 1None9.6%90.4%
Yuma CountyZone 1None49.2%50.8%
Morgan CountyZone 1NoneNone100%
Weld CountyZone 1None33.9%66.2%
Colorado64 counties, pooled by land areaVariesNone25.2%74.8%

The map rates the ground, not the air in any home.

Local help

Logan County, Local resources

Radon testing and mitigation in Logan County

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

Logan County, Questions

Questions about radon in Logan County

Are radon levels high in Logan County?

In 2023, 23.8% of the radon tests reported to CDC for Logan County, Colorado were at or above 4 pCi/L, and the median reported pre-mitigation result was 2.3 pCi/L. Of 50 Colorado counties with 30 or more tests for the same period, 12 reported a higher share; pooled, the state comes to 47.0%.

Which counties border Logan County?

Logan County borders 8 counties: Cheyenne County, NE, Phillips County, CO, Sedgwick County, CO, Kimball County, NE, Washington County, CO, Yuma County, CO, Morgan County, CO and Weld County, CO.

Products

Logan County, Products

Testing a home in Logan County

In Logan County, 58.8% of 80 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 Logan 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

Logan County is in EPA Zone 1, the highest predicted radon potential. Best radon monitors for Zone 1 counties like Logan County

Explore

Logan County, Bordering counties

Counties bordering Logan County

Calculated by Radon411

Logan County, Cities and towns

Cities and towns in Logan County

About 20,654 people live in Logan County by the Census Bureau's estimate for July 1, 2025, 567 fewer than in 2020 (−2.7%). That works out to 11 people per square mile of land. Sterling alone is home to 13,054 of them, 63.2% of the total. Together its 6 incorporated places hold 69.4% of those residents; the other 30.6% live outside any of them. Reported testing is thin here: 80 tests over 2008 to 2017, or 3.9 for every 1,000 residents (2025 estimate), where Colorado as a whole comes to 16.0.

From Sterling to Crook, CDC publishes no figure by town: each reads Logan County's.

The cities and towns in Logan County by residents, July 1, 2025
PlaceResidentsSince 2020Share of residents
Sterling13,054−2.7%63.2%
Fleming421−2.5%2.0%
Merino276−2.5%1.3%
Iliff246+0.8%1.2%
Peetz202−4.7%1.0%
Crook125−4.6%0.6%

6 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).

Logan County, Homes

Homes in Logan County

Logan County is a place of houses on their own lots: 76% of its 8,709 homes are detached single-family houses, against 62% across Colorado. The homes are older than Colorado's as a whole: half were built before 1962 (1987 for Colorado), and 48% date from before 1960. 68% 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 in Logan County, Colorado, 2019 to 2023
HomesLogan CountyColorado
Housing units8,7092,545,124
Detached houses76%62%
In buildings of 5 or more7%22%
Mobile homes10%4%
Built before 196048%16%
Built since 20009%31%
Middle year built19621987
Owner-occupied68%66%

Census Bureau, American Community Survey, 2019 to 2023: estimates from a sample of homes, looser for a small place. Shares by Radon411.