Missouri Radon Map, Levels & Testing Guide
Browse the 115 listed county pages surfaced for Missouri. Open a listed county to compare its EPA zone, source caveats, testing meaning, and when mitigation pricing becomes worth checking.
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Official Evidence in Missouri
115 of 115 listed counties have official evidence
Open a county page to see the official source context: measurement fields, local burden, state percentile, and the next step for no reading, 2.0-3.9, or 4.0+ pCi/L.
100%
covered
Measured
115
State source
115
CDC source
0
Needs source detail
0
Measured Risk Leaders in Missouri
County rankings from actual reported radon tests
These lists rank the visible Missouri county pages by measured radon signals, not by the EPA zone label alone. Use them to spot where the state hub has a real data story before opening individual county pages.
115
measured counties
State-level evidence read
This hub has measured high-burden counties, so the first click should be evidence-led.
The state hub is now doing a decision job: it separates first-click counties, retest counties, and lower-signal counties from 115 visible county measurement rows. 47 counties cross the high measured-burden band, so those pages should answer testing and 4.0+ action questions most directly.
First-click counties
Open Atchison County first when you need the strongest local answer. It is tagged Test-now from 67.1% 4.0+ - 6.9 pCi/L primary - 89 tests. 75 visible measured counties are elevated or high enough to review before lower-signal counties.
Buyer/seller lane
Buyer/seller lane: start with the elevated or high counties, require a fresh lowest-level test, and turn any 4.0+ property result into quote or credit math. The hub has 115 state-source county rows to support that routing.
Retest lane
Retest lane: 2.0-3.9 pCi/L deserves more caution in the elevated/high county set than in lower-signal counties. The hub should send those users to county pages before product or cost paths.
Best county pages to open first
Start with these local evidence pages
Ranked by measured burden, 4.0+ share, test volume, and whether the EPA zone understates the measurement signal.
Atchison County
MO DHSS
67.1% 4.0+ - 6.9 pCi/L primary - 89 tests
Atchison County is a first-click page: 67.1% of reported tests at or above 4.0 and 6.9 pCi/L primary result. Route no-reading users to a test now and 4.0+ users to quote or credit planning.
Andrew County
MO DHSS
57.5% 4.0+ - 7.5 pCi/L primary - 144 tests
Andrew County is a first-click page: 57.5% of reported tests at or above 4.0 and 7.5 pCi/L primary result. Route no-reading users to a test now and 4.0+ users to quote or credit planning.
Oregon County
MO DHSS
70.0% 4.0+ - 4.9 pCi/L primary - 21 tests
Oregon County is a first-click page: 70.0% of reported tests at or above 4.0 and 4.9 pCi/L primary result. Route no-reading users to a test now and 4.0+ users to quote or credit planning.
Holt County
MO DHSS
64.0% 4.0+ - 6.2 pCi/L primary - 27 tests
Holt County is a first-click page: 64.0% of reported tests at or above 4.0 and 6.2 pCi/L primary result. Route no-reading users to a test now and 4.0+ users to quote or credit planning.
Highest 4.0+ share
Primary result 4.9 pCi/L - high-end 9.3 pCi/L
MO DHSS
Primary result 6.9 pCi/L - high-end 26.0 pCi/L
MO DHSS
Primary result 6.2 pCi/L - high-end 15.3 pCi/L
MO DHSS
Primary result 7.5 pCi/L - high-end 90.6 pCi/L
MO DHSS
Primary result 5.9 pCi/L - high-end 39.4 pCi/L
MO DHSS
Highest high-end reading
4.0+ share 26.7% - primary result 3.8 pCi/L
MO DHSS
4.0+ share 43.3% - primary result 6.0 pCi/L
MO DHSS
4.0+ share 29.3% - primary result 3.8 pCi/L
MO DHSS
4.0+ share 28.0% - primary result 3.7 pCi/L
MO DHSS
4.0+ share 41.1% - primary result 5.7 pCi/L
MO DHSS
Most reported tests
4.0+ share 28.0% - primary result 3.7 pCi/L
MO DHSS
4.0+ share 45.2% - primary result 5.6 pCi/L
MO DHSS
4.0+ share 29.3% - primary result 3.8 pCi/L
MO DHSS
4.0+ share 37.5% - primary result 4.3 pCi/L
MO DHSS
4.0+ share 43.3% - primary result 6.0 pCi/L
MO DHSS
Measured pattern
Among 115 visible counties with measurement tables, 47 land in the high measured-burden band and 75 land in high or elevated measured-burden bands. That lets this hub rank counties by observed test distribution instead of repeating the EPA map.
Map vs measurements
64 elevated measured counties are not EPA Zone 1. Those are the pages where the actual test distribution matters more than a map-only answer.
Source strategy
All measured rows shown here use state-specific official sources, so this hub can make source-backed county comparisons without leaning on a national fallback.
Already Tested
View Missouri Cost Estimates
If you already have a radon result, skip the directory and move straight to local price guidance.
Understand the Number
2.0 vs 4.0 vs 8.0 pCi/L
Use the parent levels guide if you need the plain-English meaning of a radon result before browsing counties.
Need a Number First
Read the Testing Guide
Use the fastest valid radon test setup before you compare quotes or ask whether mitigation is worth it.
Browse Counties
Jump to the Directory
Open your county to see its EPA zone, testing meaning, and the point where mitigation becomes worth pricing.
Official State Resource
Missouri radon program and rules
Use the state program link to verify local radon guidance, disclosure language, and contractor credential expectations before you act on an estimate.
Disclosure rule tracked
Missouri requires sellers to complete a Seller's Disclosure Statement, which includes known environmental hazards.
State licensing required
Missouri requires radon professionals to be licensed by the Missouri Department of Health and Senior Services.
Already tested? Get your itemized mitigation cost estimate.
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