Idaho Radon Map, Levels & Testing Guide
Browse the 44 listed county pages surfaced for Idaho. Open a listed county to compare its EPA zone, source caveats, testing meaning, and when mitigation pricing becomes worth checking.
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Moderate
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Official Evidence in Idaho
44 of 44 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
44
State source
0
CDC source
44
Needs source detail
0
Measured Risk Leaders in Idaho
County rankings from actual reported radon tests
These lists rank the visible Idaho 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.
44
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 44 visible county measurement rows. 28 counties cross the high measured-burden band, so those pages should answer testing and 4.0+ action questions most directly.
First-click counties
Open Butte County first when you need the strongest local answer. It is tagged Test-now from 75.9% 4.0+ - 21.8 pCi/L primary - 19 tests. 38 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 44 CDC-backed 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.
Butte County
CDC Tracking
75.9% 4.0+ - 21.8 pCi/L primary - 19 tests
Butte County is a first-click page: 75.9% of reported tests at or above 4.0 and 21.8 pCi/L primary result. Route no-reading users to a test now and 4.0+ users to quote or credit planning.
Clark County
CDC Tracking
75.0% 4.0+ - 13.9 pCi/L primary - 1 tests
Clark County is a first-click page: 75.0% of reported tests at or above 4.0 and 13.9 pCi/L primary result. Route no-reading users to a test now and 4.0+ users to quote or credit planning.
Kootenai County
CDC Tracking
61.0% 4.0+ - 13.4 pCi/L primary - 2,103 tests
Kootenai County is a first-click page: 61.0% of reported tests at or above 4.0 and 13.4 pCi/L primary result. Route no-reading users to a test now and 4.0+ users to quote or credit planning.
Madison County
CDC Tracking
63.7% 4.0+ - 11.0 pCi/L primary - 200 tests
Madison County is a first-click page: 63.7% of reported tests at or above 4.0 and 11.0 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 9.1 pCi/L - high-end 29.0 pCi/L
CDC Tracking
Primary result 21.8 pCi/L - high-end 89.8 pCi/L
CDC Tracking
Primary result 13.9 pCi/L - high-end 26.4 pCi/L
CDC Tracking
Primary result 7.5 pCi/L - high-end 16.3 pCi/L
CDC Tracking
Primary result 9.0 pCi/L - high-end 33.0 pCi/L
CDC Tracking
Highest high-end reading
4.0+ share 61.0% - primary result 13.4 pCi/L
CDC Tracking
4.0+ share 53.3% - primary result 12.2 pCi/L
CDC Tracking
4.0+ share 51.6% - primary result 9.3 pCi/L
CDC Tracking
4.0+ share 63.0% - primary result 10.6 pCi/L
CDC Tracking
4.0+ share 52.0% - primary result 6.2 pCi/L
CDC Tracking
Most reported tests
4.0+ share 25.2% - primary result 3.2 pCi/L
CDC Tracking
4.0+ share 61.0% - primary result 13.4 pCi/L
CDC Tracking
4.0+ share 40.1% - primary result 4.3 pCi/L
CDC Tracking
4.0+ share 41.9% - primary result 6.0 pCi/L
CDC Tracking
4.0+ share 10.7% - primary result 2.2 pCi/L
CDC Tracking
Measured pattern
Among 44 visible counties with measurement tables, 28 land in the high measured-burden band and 38 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
19 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
The measured rows shown here use CDC Tracking. This is still official evidence, but the hub should keep source caveats visible until a stable state table is available.
Already Tested
View Idaho 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
Idaho 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
Idaho requires sellers to complete a Property Condition Disclosure Form, which covers known environmental hazards including radon.
Credential note
Idaho does not require state licensing for radon professionals.
Already tested? Get your itemized mitigation cost estimate.
View Idaho Mitigation Cost Estimates ->