Long-term kit
RL116 long-term radon test kit
- Lab fee extra
Method: Alpha track
In home: 90 days to 12 months
Locations and reports
Radon Levels in Bonner County, Idaho
EPA puts Bonner County in Zone 1, its highest radon zone, and 33.0% of its 321 reported radon tests (2008 to 2017, laboratory totals) 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
33.0%
8.5 pts below ID
- Bonner
- 33.0%
- Idaho
- 41.5%
321 tests, 2008 to 2017
Median result
2.3pCi/L
Below action level
- Bonner
- 2.3 pCi/L
- EPA
- 4.0 pCi/L
Midpoint of the tests, 2008 to 2017
Tests reported
321
10th of 37 by tests
- Bonner
- 321
- Ada
- 3,030
Reported to CDC before any fix, 2008 to 2017
EPA radon zone
Zone 1
Highest potential
- Zone 1
- 2
- 3
1 highest, 3 lowest
EPA predicts over 4 pCi/L indoors
Rank in Idaho
20 of 37
Middle half
- Bonner
- 33.0%
- Bear Lake
- 78.1%
By share, of 37 with 30+ tests
Read a result for Bonner County
Starts at Bonner 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. Bonner County's median reported result, 2008 to 2017.
The data
Bonner County, At a glance
Bonner County at a glance
Predicted: EPA radon zone
EPA Zone 1: highest predicted potential
EPA puts all of Bonner 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 Bonner County, 2008 to 2017, laboratory
Under 2 pCi/L: 46%2 to 4 pCi/L: 21%4 pCi/L and above: 33%
Of 321 pre-mitigation tests reported to CDC, not homes in this area.
| Result band | Tests Measured | Share Measured |
|---|---|---|
| Under 2 pCi/L | 147 | 45.8% |
| 2 to 4 pCi/L | 68 | 21.2% |
| 4 pCi/L and above | 106 | 33.0% |
What these figures count
These are the 321 tests reported to CDC for Bonner County over 2008 to 2017 (laboratory totals), 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: 2008 to 2017, laboratory. Measured data period: 2005 to 2017 (every CDC figure on file).
Bonner County, Compared
Bonner County radon figures, compared
Calculated by Radon411In Bonner County, about 3 in 10 reported tests over the 2008 to 2017 laboratory totals (106 of 321) were at or above EPA's action level. Against the national pool of 35.7%, the gap is 2.7 points lower. Across 44 Idaho counties pooled together, 41.5% of tests reached that level, so Bonner County runs 8.5 points below its state.
Of 7 neighbours with a figure, 6 reported a larger share at or above 4 pCi/L and 1 a smaller one; the spread is 20.0% (Boundary County) to 63.2% (Pend Oreille County, WA). By share, Bonner County is 20th of 37 Idaho counties with 30 or more tests for the same period.
Half the tests came in under 2.3 pCi/L and half over it; the single highest reached 78.5 pCi/L. Below the action level, 147 tests (45.8%) came in under 2 pCi/L, against 31.5% statewide, and 68 tests (21.2%) fell between 2 and 4, against 26.9% statewide.
Zone 1 on EPA's map (predicted average above 4 pCi/L) and a 33.0% share point the same way here. USGS geology rates 100% of the county's land high radon potential. CDC also counts 29 tests taken after mitigation in Bonner County for the same period: tests in homes where a fix was already in.
CDC's ten-year totals for Bonner County went from 181 tests (2005 to 2014) to 321 (2008 to 2017), the share going from 30.9% to 33.0%.
Pooled shares: Radon411's sum of CDC's county counts for one period.
Bonner County, Geology
The ground under Bonner County
PredictedUSGS's geologic map puts all of Bonner County's mapped land in one class: high radon potential. All of it lies in the area the map calls Northern Rocky Mountain Province, 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 |
|---|---|---|---|---|
| Northern Rocky Mountain Province | Diorite and granite of the Idaho batholith. | 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.
Bonner County beside the ground around it
Bonner County has more high-potential ground than Idaho as a whole: 100% of its land against 50.7%. Of the 7 counties that border it, none has as large a share of high-potential ground; Sanders County, MT comes nearest at 100%.
The map rates the ground, not the air in any home.
Local help
Bonner County, Local resources
Radon testing and mitigation in Bonner County
- DHW Environmental Health ProgramDHW Environmental Health Program, run by Idaho Department of Health and Welfare, offers free or discounted test kits, and answers questions about testing and mitigation in Idaho.Visit the program’s page(opens in a new tab)
- Free and low-cost kitsThe program says:
Order a free radon test kit.
- Compare kits
- See the Idaho directoryNo professionals are listed in Idaho yet. The state program can point you to registered testers and mitigators.
What Idaho's program says
- Phone
- 800-445-8647
- radon@dhw.idaho.gov
What it means
Bonner County, Questions
Questions about radon in Bonner County
Are radon levels high in Bonner County?
Over the 2008 to 2017 laboratory totals, 33.0% of the radon tests reported to CDC for Bonner County, Idaho were at or above 4 pCi/L, and the median reported pre-mitigation result was 2.3 pCi/L. Of 37 Idaho counties with 30 or more tests for the same period, 19 reported a higher share; pooled, the state comes to 41.5%.
Which counties border Bonner County?
Bonner County borders 7 counties: Boundary County, ID, Pend Oreille County, WA, Kootenai County, ID, Lincoln County, MT, Shoshone County, ID, Spokane County, WA and Sanders County, MT.
Products
Bonner County, Products
Testing a home in Bonner County
In Bonner County, 33.0% of 321 tests reported to CDC over the 2008 to 2017 laboratory totals reached 4 pCi/L, against 41.5% pooled across Idaho. In Zone 1 the year-round level in Bonner 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
Monitor
RM-63Pro rechargeable radon monitor with a touchscreen
- C-NRPP 2024/25: Not included
- Battery
- Alarm
- Screen
Method: Semiconductor sensor
Short-term kitKidde
442020 short-term charcoal radon test kit
- Lab fee included
Method: Charcoal
In home: 3 days
- See every kit and monitor Test kits and monitors
Test kits and monitors: 1 of 3
Bonner County is in EPA Zone 1, the highest predicted radon potential. Best radon monitors for Zone 1 counties like Bonner County
Explore
Bonner County, Bordering counties
Counties bordering Bonner County
Calculated by Radon411- Radon levels in Pend Oreille County, WAEPA zone 1
63.2%at or above 4 pCi/L
Median 4.8 pCi/L · 38 tests · 30.2 points above Bonner County
- Radon levels in Shoshone County, IDEPA zone 1
63.0%at or above 4 pCi/L
Median 5.7 pCi/L · 81 tests · 30.0 points above Bonner County
- Radon levels in Kootenai County, IDEPA zone 1
61.0%at or above 4 pCi/L
Median 6.0 pCi/L · 2,955 tests · 28.0 points above Bonner County
- Radon levels in Lincoln County, MTEPA zone 1
51.4%at or above 4 pCi/L
Median 4.0 pCi/L · 74 tests · 18.4 points above Bonner County
- Radon levels in Sanders County, MTEPA zone 1
50.0%at or above 4 pCi/L
Median 4.0 pCi/L · 38 tests · 17.0 points above Bonner County
- Radon levels in Spokane County, WAEPA zone 1
41.4%at or above 4 pCi/L
Median 2.9 pCi/L · 3,125 tests · 8.4 points above Bonner County
- Radon levels in Boundary County, IDEPA zone 1
20.0%at or above 4 pCi/L
Median 2.1 pCi/L · 45 tests · 13.0 points below Bonner County
Bonner County, Cities and towns
Cities and towns in Bonner County
Bonner County is growing: the Census Bureau puts it at 54,420 residents on July 1, 2025, up 14.8% from 47,411 in 2020. That works out to 31 people per square mile of land. No town dominates: Sandpoint, the largest, has 10,645 residents, 19.6% of the total. Together its 9 incorporated places hold 33.0% of those residents; the other 67.0% live outside any of them. CDC's 321 reported tests for 2008 to 2017 work out to 5.9 per 1,000 residents (2025 estimate), close to Idaho's 6.4.
From Sandpoint to Hope, CDC publishes no figure by town: each reads Bonner County's.
| Place | Residents | Since 2020 | Share of residents |
|---|---|---|---|
| Sandpoint | 10,645 | +22.0% | 19.6% |
| Ponderay | 2,024 | +55.3% | 3.7% |
| Priest River | 1,851 | +10.8% | 3.4% |
| Dover | 1,164 | +49.8% | 2.1% |
| Kootenai | 1,091 | +13.9% | 2.0% |
| Clark Fork | 579 | +11.3% | 1.1% |
| Oldtown | 262 | +18.0% | 0.5% |
| East Hope | 252 | +9.6% | 0.5% |
| Hope | 108 | +9.1% | 0.2% |
9 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).
Bonner County, Homes
Homes in Bonner County
Of Bonner County's 26,623 homes, 74% are detached houses, against 74% across Idaho; 12% are mobile homes. Half of its homes were built before 1990, close to Idaho's 1990: 17% date from before 1960 and 33% from 2000 or later. Owners live in 78% of the occupied homes (Idaho: 72%), so for most households a test and a fix are their own to order.
| Homes | Bonner County | Idaho |
|---|---|---|
| Housing units | 26,623 | 776,683 |
| Detached houses | 74% | 74% |
| In buildings of 5 or more | 6% | 9% |
| Mobile homes | 12% | 7% |
| Built before 1960 | 17% | 18% |
| Built since 2000 | 33% | 35% |
| Middle year built | 1990 | 1990 |
| Owner-occupied | 78% | 72% |
Census Bureau, American Community Survey, 2019 to 2023: estimates from a sample of homes, looser for a small place. Shares by Radon411.