Short-term kit
RA100 short-term liquid scintillation radon test kit
- Lab fee extra
Method: Liquid scintillation
In home: 48 to 96 hours
Locations and reports
Radon Levels in Malheur County, Oregon
EPA puts Malheur County in Zone 2, its middle radon zone, and only 25 radon tests from it are on file with CDC (2023). Homes with elevated levels occur in all three zones, so only a test measures yours.
Data checked By Radon411Methodology
Nearest county
39.1%
Union County, 147 miles
- Union
- 39.1%
- Oregon
- 21.5%
Share at 4+ pCi/L, 64 tests, 2016
Ground above low
99.8%
37.5 pts above Oregon
- Malheur
- 99.8%
- Oregon
- 62.3%
Share of land USGS rates moderate or high potential
Tests reported
27
Too few for a share
- Malheur
- 27
- Needed
- 30
2020
EPA radon zone
Zone 2
Moderate potential
- 1
- Zone 2
- 3
1 highest, 3 lowest
EPA predicts 2 to 4 pCi/L indoors
Read a result for Malheur County
Starts at EPA's action level
EPA’s own thresholds; the figures are the area’s, never this home’s.
EPA’s reading of 4.0 pCi/L
At or above 4 pCi/L
- Under 20 to 1.9 pCi/L
- 2 to 4consider a fix
- 4 and aboveEPA says fix it
This result is at or above 4 pCi/L. EPA recommends fixing a home when the radon level is 4 pCi/L or higher.
The data
Malheur County, At a glance
Malheur County at a glance
Predicted: EPA radon zone
EPA Zone 2: moderate predicted potential
Malheur County is a
USGS geologic potential: Moderate across 100% of the county's area
Predicted: EPA Map of Radon Zones
Measured: tests reported to CDC
Radon tests reported for Malheur County, 2023
| Year | Share of reported tests at or above 4 pCi/L |
|---|---|
| 2014 | 0.0% |
| 2015 | 0.0% |
| 2016 | 0.0% |
| 2017 | 22.2% |
| 2018 | 22.2% |
| 2019 | 50.0% |
| 2020 | 3.7% |
| 2021 | 15.4% |
| 2022 | 57.1% |
| 2023 | 0.0% |
2023: 0.0%. Across these years the share ran from 0.0% to 57.1%. Each column counts radon tests reported to CDC that year, not homes.
What these figures count
Only 25 tests were reported to CDC for Malheur County over 2023, and tests are often run on homes being sold or already suspected of a problem: so few describe neither the county nor this house.
Measured: CDC tracking data. Figure above: 2023. Measured data period: 2005 to 2023 (every CDC figure on file).
Malheur County, Compared
Malheur County radon figures, compared
Calculated by Radon411CDC's largest figure for Malheur County rests on 27 tests in 2020, 1 of them at or above 4 pCi/L, so each test moves its share by 3.7 points and no rank or comparison is drawn from it. Results reached as high as 19.7 pCi/L, with a middle value of 0.9 pCi/L.
The nearest counties with a figure are Union County (147 miles away) at 39.1%, Deschutes County (188 miles away) at 6.7% and Wasco County (222 miles away) at 10.0%. Pooled across 35 Oregon counties, 21.5% of reported tests reached that level; across every county in the country with a figure, 31.2%.
Statewide for the same period, Union County reported the highest share (39.1%) and Deschutes County the lowest (6.7%). EPA's 1993 map puts Malheur County in Zone 2, its middle label: a predicted county average between 2 and 4 pCi/L. USGS geology rates 100% of the county's land moderate radon potential.
Pooled shares: Radon411's sum of CDC's county counts for one period.
Malheur County, Geology
The ground under Malheur County
PredictedMost of the ground under Malheur County is one class on USGS's geologic map: 99.6% of its land is moderate radon potential, with 0.2% high and 0.2% low. The map puts 69.0% of Malheur County in the area it calls Owyhee Upland and 11.9% in Blue Mountains, with 2 smaller areas beside them. USGS gives both a radon index of 9, in the moderate band (9 to 11).
| Area | The rock, in USGS's words | Potential | Radon index | Share of land |
|---|---|---|---|---|
| Owyhee Upland | Tertiary and Quaternary basalt, andesite, and rhyolite. | Moderate | 9 | 69.0% |
| Blue Mountains | Tertiary basalt and andesite, tuffaceous sedimentary rocks, and tuff. | Moderate | 9 | 11.9% |
| Northern Basin and Range | Basalt, andesite, rhyolite, tuffaceous sedimentary rocks. Low soil uranium content in the western part, uranium-bearing volcanic rocks and uranium deposits in the eastern part of the province. | Moderate | 9 | 10.2% |
| Eastern Snake river plain and Malheur-Boise-King Section | Basalt flows. | Moderate | 10 | 8.5% |
Names, descriptions and indexes: U.S. Geological Survey, Geologic Radon Potential Map (2025). Shares: Radon411, from the map cut to the boundary.
Malheur County beside the ground around it
On high-potential ground Malheur County is close to Oregon as a whole: 0.2% of its land against none. Of the 8 counties that border it, 1 has more high-potential ground, Humboldt County, NV the most at 25.2%.
The map rates the ground, not the air in any home.
Local help
Malheur County, Local resources
Radon testing and mitigation in Malheur 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
Malheur County, Questions
Questions about radon in Malheur County
Are radon levels high in Malheur County?
In 2023, 0.0% of the radon tests reported to CDC for Malheur County, Oregon were at or above 4 pCi/L, and the median reported pre-mitigation result was 1.1 pCi/L. Of the 8 nearest counties with a figure, within 274 miles, the share of tests at or above 4 pCi/L runs from 6.7% to 39.1%.
Which counties border Malheur County?
Malheur County borders 8 counties: Canyon County, ID, Payette County, ID, Harney County, OR, Owyhee County, ID, Washington County, ID, Baker County, OR, Grant County, OR and Humboldt County, NV.
Products
Malheur County, Products
Testing a home in Malheur County
No CDC figure names Malheur County; the nearest county with one, Union County (147 miles away), reported 39.1% of its tests at or above 4 pCi/L in 2016, the only reading nearby until a test of this home. In Zone 2 a short-term kit (2 to 90 days) is the quick first check in Malheur County; a long-term test tells the year-round average.
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
MonitorForensics Detectors
FD-65-RADON rechargeable radon detector with a color screen
- C-NRPP 2024/25: Not included
- Battery
- Alarm
- Screen
Method: Semiconductor sensor
First reading: Within 6 hours
- See every kit and monitor Test kits and monitors
Test kits and monitors: 1 of 3
Explore
Malheur County, Bordering counties
Counties bordering Malheur County
Calculated by Radon411- Radon levels in Baker County, OREPA zone 2
33.3%at or above 4 pCi/L
Median 2.0 pCi/L · 3 tests
- Radon levels in Harney County, OREPA zone 2
0.0%at or above 4 pCi/L
Median 1.4 pCi/L · 4 tests
- Radon levels in Grant County, OREPA zone 2
0.0%at or above 4 pCi/L
Median 0.2 pCi/L · 1 test
- Radon levels in Canyon County, IDEPA zone 2
No CDC figure for 2016; its page reads it against its own neighbours.
- Radon levels in Payette County, IDEPA zone 2
No CDC figure for 2016; its page reads it against its own neighbours.
- Radon levels in Owyhee County, IDEPA zone 2
No CDC figure for 2016; its page reads it against its own neighbours.
- Radon levels in Washington County, IDEPA zone 3
No CDC figure for 2016; its page reads it against its own neighbours.
- Radon levels in Humboldt County, NVEPA zone 2
No CDC figure for 2016; its page reads it against its own neighbours.
Malheur County, Cities and towns
Cities and towns in Malheur County
The Census Bureau estimates 32,261 residents in Malheur County for July 1, 2025, 611 more than in 2020 (+1.9%). Spread over its land, that is 3.3 people to the square mile. Its largest town, Ontario, has 11,957 residents, 37.1% of the total. Together its 5 incorporated places hold 54.5% of those residents; the other 45.5% live outside any of them. CDC's 27 reported tests for 2020 work out to 0.8 per 1,000 residents (2025 estimate), close to Oregon's 1.3.
From Ontario to Jordan Valley, CDC publishes no figure by town: each reads Malheur County's.
| Place | Residents | Since 2020 | Share of residents |
|---|---|---|---|
| Ontario | 11,957 | +1.6% | 37.1% |
| Nyssa | 3,257 | +1.4% | 10.1% |
| Vale | 2,055 | +7.9% | 6.4% |
| Adrian | 161 | +2.5% | 0.5% |
| Jordan Valley | 142 | +2.9% | 0.4% |
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).
Malheur County, Homes
Homes in Malheur County
Of Malheur County's 11,678 homes, 65% are detached houses, against 63% across Oregon; 17% are mobile homes. Half of its homes were built before 1974, close to Oregon's 1980: 30% date from before 1960 and 12% from 2000 or later. 63% 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 | Malheur County | Oregon |
|---|---|---|
| Housing units | 11,678 | 1,838,631 |
| Detached houses | 65% | 63% |
| In buildings of 5 or more | 8% | 17% |
| Mobile homes | 17% | 8% |
| Built before 1960 | 30% | 23% |
| Built since 2000 | 12% | 24% |
| Middle year built | 1974 | 1980 |
| Owner-occupied | 63% | 63% |
Census Bureau, American Community Survey, 2019 to 2023: estimates from a sample of homes, looser for a small place. Shares by Radon411.