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 Broomfield County, Colorado
EPA puts Broomfield County in Zone 1, its highest radon zone, and 36.9% of its 758 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
36.9%
2.0 pts below CO
- Broomfield
- 36.9%
- Colorado
- 38.9%
758 tests, 2023
Median result
2.3pCi/L
Below action level
- Broomfield
- 2.3 pCi/L
- EPA
- 4.0 pCi/L
Midpoint of the tests, 2023
Tests reported
758
9th of 38 by tests
- Broomfield
- 758
- 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
25 of 38
Middle half
- Broomfield
- 36.9%
- Park
- 57.5%
By share, of 38 with 30+ tests
Read a result for Broomfield County
Starts at Broomfield County's median, 2.3 pCi/L
EPA’s own thresholds; the figures are the area’s, never this home’s.
EPA’s reading of 2.3 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. Broomfield County's median reported result, 2023.
The data
Broomfield County, At a glance
Broomfield County at a glance
Predicted: EPA radon zone
EPA Zone 1: highest predicted potential
EPA puts all of Broomfield County in
USGS geologic potential: High across 100% of the county's area
Predicted: EPA Map of Radon Zones
Measured: tests reported to CDC
Radon tests reported for Broomfield County, 2023
| Year | Share of reported tests at or above 4 pCi/L |
|---|---|
| 2014 | 52.5% |
| 2015 | 32.3% |
| 2016 | 31.1% |
| 2017 | 42.4% |
| 2018 | 39.7% |
| 2019 | 44.4% |
| 2020 | 26.4% |
| 2021 | 45.1% |
| 2022 | 23.7% |
| 2023 | 36.9% |
2023: 36.9%. Across these years the share ran from 23.7% to 52.5%. Each column counts radon tests reported to CDC that year, not homes.
What these figures count
These are the 758 tests reported to CDC for Broomfield 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).
Broomfield County, Compared
Broomfield County radon figures, compared
Calculated by Radon411In Broomfield County, about 4 in 10 reported tests in 2023 (280 of 758) were at or above EPA's action level. Against the national pool of 33.4%, the gap is 3.5 points higher. Across 61 Colorado counties pooled together, 38.9% of tests reached that level, so Broomfield County runs 2.0 points below its state.
Of 4 neighbours with a figure, 2 reported a larger share at or above 4 pCi/L and 2 a smaller one; the spread is 34.2% (Boulder County) to 46.0% (Weld County). By share, Broomfield County is 25th of 38 Colorado counties with 30 or more tests for the same period.
Year by year, 2014 opened at 52.5% and 2023 closed at 36.9% (down 15.6 points), with 2014 the high at 52.5%. Half the tests came in under 2.3 pCi/L and half over it; the single highest reached 70.5 pCi/L. Below the action level, 354 tests (46.7%) came in under 2 pCi/L, against 39.2% statewide, and 124 tests (16.4%) fell between 2 and 4, against 22.0% statewide.
Zone 1 on EPA's map (predicted average above 4 pCi/L) and a 36.9% share point the same way here. USGS geology rates 100% of the county's land high radon potential. CDC also counts 193 tests taken after mitigation in Broomfield County for the same period: tests in homes where a fix was already in.
The busiest year on file was 2022, with 1,016 tests reported; the quietest, 2014, had 158.
Broomfield CountyColorado, pooled
| Year | Tests | Broomfield County, at or above 4 pCi/L | Colorado, pooled |
|---|---|---|---|
| 2014 | 158 | 52.5% | 46.5% |
| 2015 | 291 | 32.3% | 47.2% |
| 2016 | 196 | 31.1% | 38.5% |
| 2017 | 257 | 42.4% | 41.0% |
| 2018 | 567 | 39.7% | 44.2% |
| 2019 | 581 | 44.4% | 44.1% |
| 2020 | 591 | 26.4% | 41.9% |
| 2021 | 495 | 45.1% | 47.3% |
| 2022 | 1,016 | 23.7% | 38.6% |
| 2023 | 758 | 36.9% | 38.9% |
Pooled shares: Radon411's sum of CDC's county counts for one period.
Broomfield County, State data
Colorado's own radon test data
MeasuredWhat Colorado's own agencies publish about radon tests in Broomfield 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 Broomfield 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
44.4%
2,041 of 4,598 tests
Median result
3.2 pCi/L
Highest result
205.0 pCi/L
Tests behind these figures
4,598 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.
Broomfield County, Geology
The ground under Broomfield County
PredictedUSGS's geologic map puts all of Broomfield County's mapped land in one class: high radon potential. All of it lies in the area the map calls High Plains, to which USGS gives a radon index of 12, in the high band (12 to 17).
| Area | The rock, in USGS's words | Potential | Radon index | Share of land |
|---|---|---|---|---|
| High Plains | Quaternary deposits and Cretaceous marine shales that locally have a high radiometric signature. | High | 12 | 100% |
Names, descriptions and indexes: U.S. Geological Survey, Geologic Radon Potential Map (2025). Shares: Radon411, from the map cut to the boundary.
Broomfield County beside the ground around it
Broomfield County has more high-potential ground than Colorado as a whole: 100% of its land against 74.8%. Of the 4 counties that border it, none has as large a share of high-potential ground; Adams County comes nearest at 100%.
The map rates the ground, not the air in any home.
Local help
Broomfield County, Local resources
Radon testing and mitigation in Broomfield 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
Broomfield County, Questions
Questions about radon in Broomfield County
Are radon levels high in Broomfield County?
In 2023, 36.9% of the radon tests reported to CDC for Broomfield County, Colorado were at or above 4 pCi/L, and the median reported pre-mitigation result was 2.3 pCi/L. Of 38 Colorado counties with 30 or more tests for the same period, 24 reported a higher share; pooled, the state comes to 38.9%.
Which counties border Broomfield County?
Broomfield County borders 4 counties: Boulder County, Jefferson County, Weld County and Adams County.
Products
Broomfield County, Products
Testing a home in Broomfield County
In Broomfield County, 36.9% of 758 tests reported to CDC in 2023 reached 4 pCi/L, against 38.9% pooled across Colorado. In Zone 1 the year-round level in Broomfield 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 monitorMonitorSafetySiren
Pro4 plug-in radon detector with a display and alarm
- C-NRPP 2024/25: Not included
- Plug-in
- Alarm
- Screen
First reading: Within 48 hours
Short-term kit
Radon Short Term Test Kit short-term charcoal radon test kit, lab fee included
- Lab fee included
Method: Charcoal
In home: 2 to 7 days
- See every kit and monitor Test kits and monitors
Test kits and monitors: 1 of 3
Broomfield County is in EPA Zone 1, the highest predicted radon potential. Best radon monitors for Zone 1 counties like Broomfield County
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Broomfield County, Bordering counties
Counties bordering Broomfield County
Calculated by Radon411- Radon levels in Weld CountyEPA zone 1
46.0%at or above 4 pCi/L
Median 3.5 pCi/L · 663 tests · 9.1 points above Broomfield County
- Radon levels in Jefferson CountyEPA zone 1
41.8%at or above 4 pCi/L
Median 3.2 pCi/L · 3,068 tests · 4.9 points above Broomfield County
- Radon levels in Adams CountyEPA zone 1
36.6%at or above 4 pCi/L
Median 2.3 pCi/L · 1,191 tests · 0.3 points below Broomfield County
- Radon levels in Boulder CountyEPA zone 1
34.2%at or above 4 pCi/L
Median 2.5 pCi/L · 1,963 tests · 2.7 points below Broomfield County
Broomfield County, Cities and towns
Cities and towns in Broomfield County
Broomfield County is growing: the Census Bureau puts it at 79,174 residents on July 1, 2025, up 6.3% from 74,482 in 2020. Packed into its land, that is 2,402 people per square mile. Broomfield, its one incorporated place, has 79,174 residents, 100.0% of the total. Testing is reported here more often than across the state: CDC's 758 reported tests for 2023 come to 9.6 for every 1,000 residents (2025 estimate), against 3.6 for Colorado.
Broomfield is the one incorporated place here; CDC publishes no figure by town, so it reads Broomfield County's.
| Place | Residents | Since 2020 | Share of residents |
|---|---|---|---|
| Broomfield | 79,174 | +6.3% | 100.0% |
One incorporated place, 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).
Broomfield County, Homes
Homes in Broomfield County
Of Broomfield County's 32,261 homes, 59% are detached houses, against 62% across Colorado; 30% are in buildings of five or more homes. Much of Broomfield County is recent building: 53% of its homes have gone up since 2000 and the middle year built is 2001, against 1987 for Colorado. 63% 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 | Broomfield County | Colorado |
|---|---|---|
| Housing units | 32,261 | 2,545,124 |
| Detached houses | 59% | 62% |
| In buildings of 5 or more | 30% | 22% |
| Mobile homes | 2% | 4% |
| Built before 1960 | 4% | 16% |
| Built since 2000 | 53% | 31% |
| Middle year built | 2001 | 1987 |
| Owner-occupied | 63% | 66% |
Census Bureau, American Community Survey, 2019 to 2023: estimates from a sample of homes, looser for a small place. Shares by Radon411.