Locations and reports
Radon in Columbia, Missouri
EPA puts Boone County, where Columbia is, in Zone 2, its middle radon zone, and high results are common there: 42.9% of the 63 radon tests reported to CDC (2023) came back 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
42.9%
7.2 pts above MO
- Boone
- 42.9%
- Missouri
- 35.7%
Boone, 3rd of 7 in MO, 2023
Median result
3.6pCi/L
Below action level
- Boone
- 3.6 pCi/L
- EPA
- 4.0 pCi/L
Midpoint of Boone's tests, 2023
Nearest county
40.8%
St. Charles, 90 miles
- St. Charles
- 40.8%
- Boone
- 42.9%
103 tests, 2023
EPA radon zone
Zone 2
Moderate potential
- 1
- Zone 2
- 3
1 highest, 3 lowest
Boone, where Columbia is
Tests reported
63
In Boone
- Boone
- 63
- St. Charles
- 103
Reported to CDC before any fix, 2023
Read a result for Columbia
Starts at Boone County's median, 3.6 pCi/L
EPA’s own thresholds; the figures are the area’s, never this home’s.
EPA’s reading of 3.6 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. Boone County's median reported result, 2023.
The data
Columbia, What is published
What is published for Columbia
Every figure for Columbia is a county's
Radon data is published by county, not by city, so for Columbia it is Boone County's: its EPA zone (Zone 2) and the 63 tests reported to CDC for 2023. Only a test tells you about one home.
Columbia covers 66.5 square miles of land, all of it in Boone County. About 130,851 people live there, 1,967 to the square mile.
Columbia, Counties
The county Columbia lies in
MeasuredBoone County's EPA zone and the figures CDC publishes for it, 2023.
Boone CountyZone 2Moderate predicted potential
- 42.9%
- Reported tests at or above 4 pCi/L
- 3.6 pCi/L
- Median reported result
- 63 tests
- Tests reported to CDC
- 10
- Annual years on file
Boone County ranks 3rd of 7 Missouri counties with 30 or more tests for that period, 7.2 points above the 35.7% pooled across Missouri's counties, 9.5 points above the national pool of 33.4%.
The counties nearest Columbia with a CDC figure for 2023, measured from the middle of the city: St. Charles County (90 miles, 40.8% of 103 tests), St. Louis County (104 miles, 22.6% of 443 tests) and Jefferson County (108 miles, 38.9% of 36 tests). Across the 6 nearest, the share at or above 4 pCi/L runs from 22.6% to 44.6%; the farthest of them, Greene County, is 129 miles away at 27.1%.
No business in the directory gives Columbia as its address; the Missouri list covers it. Missouri's other cities with a page of their own: Kansas City, Springfield and Lee's Summit.
The counties around Columbia
By distance from the middle of Columbia; counties with 30 or more tests.
Predicted: EPA Map of Radon Zones, by county. Measured: CDC tracking data, by county, 2023.
Columbia, Geology
The ground under Columbia
PredictedUSGS's geologic map puts all of Columbia's mapped land in one class: moderate radon potential. The map puts 55.2% of Columbia in the area it calls Dissected Till Plains and 44.8% in Salem Plateau. USGS gives both 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 |
|---|---|---|---|---|
| Dissected Till Plains | Till-covered Pennsylvanian sandstone, shale, and limestone. | Moderate | 11 | 55.2% |
| Salem Plateau | Ordovician dolomite, sandstone, limestone, and shale. | Moderate | 11 | 44.8% |
Names, descriptions and indexes: U.S. Geological Survey, Geologic Radon Potential Map (2025). Shares: Radon411, from the map cut to the boundary.
Columbia beside its county and Missouri
All of Columbia, like all of Boone County, is rated moderate. Across Missouri 8.2% of the land is rated high; none of Columbia's is.
The map rates the ground, not the air in any home.
Columbia, Homes
Homes in Columbia
Fewer than six in ten of Columbia's 55,441 homes are detached houses (53%, against 60% across Boone County); the rest are attached, in shared buildings or mobile. Half of its homes were built before 1993, close to Boone County's 1991: 12% date from before 1960 and 39% from 2000 or later. Most occupied homes here are rented: owners live in 49% (Boone County: 58%). A tenant can run a test; a fix is the landlord's to make.
| Homes | Columbia | Boone County | Missouri |
|---|---|---|---|
| Housing units | 55,441 | 80,912 | 2,809,501 |
| Detached houses | 53% | 60% | 70% |
| In buildings of 5 or more | 27% | 19% | 13% |
| Mobile homes | 2% | 4% | 5% |
| Built before 1960 | 12% | 11% | 28% |
| Built since 2000 | 39% | 35% | 21% |
| Middle year built | 1993 | 1991 | 1978 |
| Owner-occupied | 49% | 58% | 68% |
Census Bureau, American Community Survey, 2019 to 2023: estimates from a sample of homes, looser for a small place. Shares by Radon411.
Local help
Columbia, Local resources
Local resources for Columbia
Who to ask in Missouri: its radon program, test kits and professionals.
- Missouri Radon ProgramRun by Missouri Department of Health and Senior Services, phone 573-751-6102.Visit the program’s page(opens in a new tab)
- Free and low-cost kitsThe program says:
Free radon test kits are available for Missouri residents (limit one per household).
- Compare kits
- Professionals in MissouriRadon testers and mitigators in Missouri, each with how its listing was checked.
The program's own words on licensing are on the Missouri page.
What it means
Columbia, Questions
Questions about radon in Columbia
What radon zone is Columbia in?
Columbia has no zone of its own: it shares Boone County's, Zone 2, the map's middle class: a predicted county average of 2 to 4 pCi/L.
What are radon levels in Columbia?
42.9% of the 63 tests reported from Boone County for 2023 were at or above 4 pCi/L, the level at which EPA says to fix a home: high results are ordinary around Columbia. The median reported result was 3.6 pCi/L.
Should I test my home in Columbia?
Yes. About 27 of the 63 tests reported from Boone County were at or above 4 pCi/L. That is above Missouri's pooled 35.7%, and ranks Boone County 3rd of the 7 Missouri counties with 30 or more tests. No map says which homes those are. How to test a home.
What ground is Columbia built on, as far as radon goes?
55.2% of Columbia sits on what USGS's map calls "Dissected Till Plains", rated moderate for radon potential, radon index 11; another 44.8% is "Salem Plateau", in the same class.
Is radon higher in the counties around Columbia?
Some are and some are not. Against Boone County's 42.9%, 2 of the 6 nearest counties with a figure report more and 4 less, from St. Louis County (22.6%, 104 miles off) to Clay County (44.6%, 115 miles off).
The answers use the published figures of Boone County, the county Columbia lies in.
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