Short-term kitFirst Alert
RD1 short-term charcoal radon test kit
- Lab fee included
Method: Charcoal
In home: 2 to 4 days
Locations and reports
Radon Levels in Benton County, Oregon
EPA puts Benton County in Zone 3, its lowest radon zone, and 15.6% of its 32 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
15.6%
3.3 pts below OR
- Benton
- 15.6%
- Oregon
- 18.9%
32 tests, 2023
Median result
0.9pCi/L
Below action level
- Benton
- 0.9 pCi/L
- EPA
- 4.0 pCi/L
Midpoint of the tests, 2023
Tests reported
32
14th of 14 by tests
- Benton
- 32
- Multnomah
- 792
Reported to CDC before any fix, 2023
EPA radon zone
Zone 3
Lower potential
- 1
- 2
- Zone 3
1 highest, 3 lowest
EPA predicts under 2 pCi/L indoors
Rank in Oregon
8 of 14
Middle half
- Benton
- 15.6%
- Hood River
- 39.0%
By share, of 14 with 30+ tests
Read a result for Benton County
Starts at Benton County's median, 0.9 pCi/L
EPA’s own thresholds; the figures are the area’s, never this home’s.
EPA’s reading of 0.9 pCi/L
Below 2 pCi/L
- Under 20 to 1.9 pCi/L
- 2 to 4consider a fix
- 4 and aboveEPA says fix it
This result is below 2 pCi/L, the level at which EPA says a fix should be considered. Benton County's median reported result, 2023.
The data
Benton County, At a glance
Benton County at a glance
Predicted: EPA radon zone
EPA Zone 3: lower predicted potential
USGS geologic potential: Low across 83% of the county's area
Predicted: EPA Map of Radon Zones
Measured: tests reported to CDC
Radon tests reported for Benton County, 2023
| Year | Share of reported tests at or above 4 pCi/L |
|---|---|
| 2014 | 17.1% |
| 2015 | 16.9% |
| 2016 | 11.1% |
| 2017 | 13.6% |
| 2018 | 8.6% |
| 2019 | 13.4% |
| 2020 | 5.0% |
| 2021 | 4.5% |
| 2022 | 12.5% |
| 2023 | 15.6% |
2023: 15.6%. Across these years the share ran from 4.5% to 17.1%. Each column counts radon tests reported to CDC that year, not homes.
What these figures count
These are the 32 tests reported to CDC for Benton 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).
Benton County, Compared
Benton County radon figures, compared
Calculated by Radon411Benton County's 32 reported tests in 2023 had a middle value of 0.9 pCi/L and a maximum of 36.1 pCi/L, and 15.6% reached 4 pCi/L. Oregon as a whole (28 Oregon counties, pooled) comes to 18.9%: 3.3 points higher than here.
Among its state's counties it ranks 8th of 14 Oregon counties with 30 or more tests for the same period. Statewide for the same period, Hood River County reported the highest share (39.0%) and Deschutes County the lowest (1.7%).
Below the action level, 22 tests (68.8%) came in under 2 pCi/L, against 59.5% statewide, and 5 tests (15.6%) fell between 2 and 4, against 21.6% statewide. The busiest year on file was 2020, with 280 tests reported; the quietest, 2023, had 32.
EPA's 1993 zone map puts Benton County in Zone 3, a predicted county average under 2 pCi/L. USGS geology rates 83% of the county's land low radon potential.
Next door, the shares run from 4.9% in Linn County to 15.5% in Lane County, with Lane County, Polk County and Lincoln County below Benton County. Over 10 years of annual figures the share held within 2 points, from 17.1% in 2014 to 15.6% in 2023; its peak was 17.1% in 2014.
Benton CountyOregon, pooled
| Year | Tests | Benton County, at or above 4 pCi/L | Oregon, pooled |
|---|---|---|---|
| 2014 | 70 | 17.1% | 25.1% |
| 2015 | 83 | 16.9% | 27.4% |
| 2016 | 90 | 11.1% | 21.5% |
| 2017 | 59 | 13.6% | 19.2% |
| 2018 | 58 | 8.6% | 19.6% |
| 2019 | 112 | 13.4% | 20.2% |
| 2020 | 280 | 5.0% | 16.8% |
| 2021 | 111 | 4.5% | 16.3% |
| 2022 | 120 | 12.5% | 20.2% |
| 2023 | 32 | 15.6% | 18.9% |
Pooled shares: Radon411's sum of CDC's county counts for one period.
Benton County, Geology
The ground under Benton County
PredictedMost of the ground under Benton County is one class on USGS's geologic map: 82.8% of its land is low radon potential, with 17.2% moderate. The map puts 82.8% of Benton County in the area it calls Coast Range and 17.2% in Wilamette Valley. USGS gives the first a radon index of 7, in the low band (5 to 8), and the second 9, in the moderate band (9 to 11).
| Area | The rock, in USGS's words | Potential | Radon index | Share of land |
|---|---|---|---|---|
| Coast Range | Northern Coast Range is marine sedimentary rocks and Tertiary mafic volcanic rocks. Southern Coast Range is Tertiary estuarine and marine sedimentary rocks, feldspathic and micaceous. | Low | 7 | 82.8% |
| Wilamette Valley | Gravelly to clayey alluvium with moderately elevated uranium content. | Moderate | 9 | 17.2% |
Names, descriptions and indexes: U.S. Geological Survey, Geologic Radon Potential Map (2025). Shares: Radon411, from the map cut to the boundary.
Benton County beside the ground around it
Oregon as a whole has more moderate-potential ground than Benton County: 62.3% of its land, against 17.2% here. Of the 4 counties that border it, 2 have more moderate-potential ground, Polk County the most at 28.1%.
The map rates the ground, not the air in any home.
Local help
Benton County, Local resources
Radon testing and mitigation in Benton County
- Oregon Radon Awareness ProgramOregon Radon Awareness Program, run by Oregon Health Authority, offers free or discounted test kits, and answers questions about testing and mitigation in Oregon.Visit the program’s page(opens in a new tab)
- Free and low-cost kitsThe program says:
Oregon Radon Awareness Program provides a FREE short-term radon test kit to those living in areas of Oregon where little radon testing has been done.
- Compare kits
- Professionals in Oregon38 professionals are listed in Oregon.
What Oregon's program says
- Radon.program@dhsoha.state.or.us
What it means
Benton County, Questions
Questions about radon in Benton County
Are radon levels high in Benton County?
In 2023, 15.6% of the radon tests reported to CDC for Benton County, Oregon were at or above 4 pCi/L, and the median reported pre-mitigation result was 0.9 pCi/L. Of 14 Oregon counties with 30 or more tests for the same period, 7 reported a higher share; pooled, the state comes to 18.9%.
Which counties border Benton County?
Benton County borders 4 counties: Lincoln County, Polk County, Linn County and Lane County.
Products
Benton County, Products
Testing a home in Benton County
In Benton County, 15.6% of 32 tests reported to CDC in 2023 reached 4 pCi/L, against 18.9% pooled across Oregon. Zone 3 is the lowest label, yet homes at or above 4 pCi/L occur in every zone: a short-term kit (2 to 90 days) is the quick first check in Benton County.
Test kits and monitors3
See every kit and monitor
Long-term kit
RL116 long-term radon test kit
- Lab fee extra
Method: Alpha track
In home: 90 days to 12 months
MonitorAEGTEST
HOUND-1011S rechargeable radon detector with a screen
- C-NRPP 2024/25: Not included
- Battery
- Alarm
- Screen
Method: Semiconductor sensor
First reading: Within 12 hours
- See every kit and monitor Test kits and monitors
Test kits and monitors: 1 of 3
Explore
Benton County, Bordering counties
Counties bordering Benton County
Calculated by Radon411- Radon levels in Lane CountyEPA zone 3
15.5%at or above 4 pCi/L
Median 1.0 pCi/L · 58 tests · 0.1 points below Benton County
- Radon levels in Polk CountyEPA zone 3
10.1%at or above 4 pCi/L
Median 1.4 pCi/L · 79 tests · 5.5 points below Benton County
- Radon levels in Lincoln CountyEPA zone 3
8.3%at or above 4 pCi/L
Median 1.1 pCi/L · 36 tests · 7.3 points below Benton County
- Radon levels in Linn CountyEPA zone 3
4.9%at or above 4 pCi/L
Median 0.8 pCi/L · 41 tests · 10.7 points below Benton County
Benton County, Cities and towns
Cities and towns in Benton County
The Census Bureau estimates 97,728 residents in Benton County for July 1, 2025, 4,126 more than in 2020 (+4.4%). That works out to 145 people per square mile of land. Corvallis alone is home to 61,499 of them, 62.9% of the total. Reported testing is thin here: 32 tests over 2023, or 0.3 for every 1,000 residents (2025 estimate), where Oregon as a whole comes to 0.5.
From Corvallis to Monroe, CDC publishes no figure by town: each reads Benton County's.
| Place | Residents | Since 2020 | Share of residents |
|---|---|---|---|
| Corvallis | 61,499 | +5.4% | 62.9% |
| Albanyextends beyond Benton County | 56,894 | +0.6% | Counted whole |
| Philomath | 5,699 | +6.7% | 5.8% |
| Adair Village | 1,010 | +2.4% | 1.0% |
| Monroe | 665 | +2.9% | 0.7% |
5 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). A place that extends beyond Benton County is counted whole, so it has no share.
Benton County, Homes
Homes in Benton County
Of Benton County's 40,565 homes, 58% are detached houses, against 63% across Oregon; 22% are in buildings of five or more homes. Half of its homes were built before 1979, close to Oregon's 1980: 20% date from before 1960 and 24% from 2000 or later. 56% of occupied homes are lived in by their owner (Oregon: 63%); in the rest a tenant can run a test, but a fix is the landlord's to make.
| Homes | Benton County | Oregon |
|---|---|---|
| Housing units | 40,565 | 1,838,631 |
| Detached houses | 58% | 63% |
| In buildings of 5 or more | 22% | 17% |
| Mobile homes | 6% | 8% |
| Built before 1960 | 20% | 23% |
| Built since 2000 | 24% | 24% |
| Middle year built | 1979 | 1980 |
| Owner-occupied | 56% | 63% |
Census Bureau, American Community Survey, 2019 to 2023: estimates from a sample of homes, looser for a small place. Shares by Radon411.