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 Clatsop County, Oregon
EPA puts Clatsop County in Zone 2, its middle radon zone, and only 6 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
Share at 4+ pCi/L
40.0%
14.6 pts above OR
- Clatsop
- 40.0%
- Oregon
- 25.4%
55 tests, 2008 to 2017
Median result
3.0pCi/L
Below action level
- Clatsop
- 3.0 pCi/L
- EPA
- 4.0 pCi/L
Midpoint of the tests, 2008 to 2017
Tests reported
55
15th of 23 by tests
- Clatsop
- 55
- Multnomah
- 12,330
Reported to CDC before any fix, 2008 to 2017
EPA radon zone
Zone 2
Moderate potential
- 1
- Zone 2
- 3
1 highest, 3 lowest
EPA predicts 2 to 4 pCi/L indoors
Rank in Oregon
2 of 23
Top quarter
- Clatsop
- 40.0%
- Union
- 42.0%
By share, of 23 with 30+ tests
Read a result for Clatsop County
Starts at Clatsop County's median, 3.0 pCi/L
EPA’s own thresholds; the figures are the area’s, never this home’s.
EPA’s reading of 3.0 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. Clatsop County's median reported result, 2008 to 2017.
The data
Clatsop County, At a glance
Clatsop County at a glance
Predicted: EPA radon zone
EPA Zone 2: moderate predicted potential
Clatsop County is a
USGS geologic potential: Moderate across 63% of the county's area
Predicted: EPA Map of Radon Zones
Measured: tests reported to CDC
Radon tests reported for Clatsop County, 2023
| Year | Share of reported tests at or above 4 pCi/L |
|---|---|
| 2014 | 42.9% |
| 2015 | 30.8% |
| 2016 | 25.9% |
| 2017 | 23.5% |
| 2018 | 25.0% |
| 2019 | 28.6% |
| 2020 | 33.3% |
| 2021 | 30.3% |
| 2022 | 30.8% |
| 2023 | 50.0% |
2023: 50.0%. Across these years the share ran from 23.5% to 50.0%. Each column counts radon tests reported to CDC that year, not homes.
What these figures count
Only 6 tests were reported to CDC for Clatsop 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).
Clatsop County, Compared
Clatsop County radon figures, compared
Calculated by Radon411In Clatsop County, about 4 in 10 reported tests over the 2008 to 2017 laboratory totals (22 of 55) were at or above EPA's action level. Against the national pool of 35.7%, the gap is 4.3 points higher. Across 34 Oregon counties pooled together, 25.4% of tests reached that level, so Clatsop County runs 14.6 points above its state.
The newest figure, in 2023, counts only 6 tests (50.0% at or above 4 pCi/L), too few to compare, so this reading uses the 55-test figure.
Of 2 neighbours with a figure, none reported a larger share at or above 4 pCi/L; the spread is 10.1% (Washington County) to 36.8% (Columbia County). By share, Clatsop County is 2nd of 23 Oregon counties with 30 or more tests for the same period.
Half the tests came in under 3.0 pCi/L and half over it; the single highest reached 42.9 pCi/L. Below the action level, 20 tests (36.4%) came in under 2 pCi/L, against 51.9% statewide, and 13 tests (23.6%) fell between 2 and 4, against 22.7% statewide.
Zone 2 on EPA's map (predicted average between 2 and 4 pCi/L) and a 40.0% share point the same way here. USGS geology rates 63% of the county's land moderate radon potential.
The busiest year on file was 2022, with 39 tests reported; the quietest, 2023, had 6.
Pooled shares: Radon411's sum of CDC's county counts for one period.
Clatsop County, Geology
The ground under Clatsop County
PredictedUSGS's geologic map splits Clatsop County: 63.3% of its land is moderate radon potential and 31.1% low. The map puts 63.3% of Clatsop County in the area it calls Columbia River Gorge and 31.1% in Coast Range. USGS gives the first a radon index of 9, in the moderate band (9 to 11), and the second 7, in the low band (5 to 8).
| Area | The rock, in USGS's words | Potential | Radon index | Share of land |
|---|---|---|---|---|
| Columbia River Gorge | River and lacustrine delta deposits and volcanic debris flows. | Moderate | 9 | 63.3% |
| 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 | 31.1% |
Names, descriptions and indexes: U.S. Geological Survey, Geologic Radon Potential Map (2025). Shares: Radon411, from the map cut to the boundary.
Clatsop County beside the ground around it
On moderate-potential ground Clatsop County is close to Oregon as a whole: 63.3% of its land against 62.3%. Of the 4 counties that border it, 1 has more moderate-potential ground, Columbia County the most at 91.6%.
The map rates the ground, not the air in any home.
Local help
Clatsop County, Local resources
Radon testing and mitigation in Clatsop 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
Clatsop County, Questions
Questions about radon in Clatsop County
Are radon levels high in Clatsop County?
In 2023, 50.0% of the radon tests reported to CDC for Clatsop County, Oregon were at or above 4 pCi/L, and the median reported pre-mitigation result was 3.9 pCi/L. Of 23 Oregon counties with 30 or more tests for the same period, 1 reported a higher share; pooled, the state comes to 25.4%.
Which counties border Clatsop County?
Clatsop County borders 4 counties: Wahkiakum County, WA, Columbia County, OR, Washington County, OR and Tillamook County, OR.
Products
Clatsop County, Products
Testing a home in Clatsop County
In Clatsop County, 40.0% of 55 tests reported to CDC over the 2008 to 2017 laboratory totals reached 4 pCi/L, against 25.4% pooled across Oregon. In Zone 2 a short-term kit (2 to 90 days) is the quick first check in Clatsop 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
Monitor
EcoQube Flex battery digital radon monitor with an e-ink screen
- C-NRPP 2024/25: Not included
- Battery
- Bluetooth
- Alarm
- Screen, app
Method: Ion chamber
First reading: Within 15 minutes
- See every kit and monitor Test kits and monitors
Test kits and monitors: 1 of 3
Explore
Clatsop County, Bordering counties
Counties bordering Clatsop County
Calculated by Radon411- Radon levels in Columbia County, OREPA zone 2
36.8%at or above 4 pCi/L
Median 1.9 pCi/L · 212 tests · 3.2 points below Clatsop County
- Radon levels in Tillamook County, OREPA zone 3
30.8%at or above 4 pCi/L
Median 1.0 pCi/L · 13 tests · 9.2 points below Clatsop County
- Radon levels in Washington County, OREPA zone 2
10.1%at or above 4 pCi/L
Median 1.0 pCi/L · 3,338 tests · 29.9 points below Clatsop County
- Radon levels in Wahkiakum County, WAEPA zone 3
0.0%at or above 4 pCi/L
Median 2.9 pCi/L · 1 test · 40.0 points below Clatsop County
Clatsop County, Cities and towns
Cities and towns in Clatsop County
About 40,926 people live in Clatsop County by the Census Bureau's estimate for July 1, 2025, 230 fewer than in 2020 (−0.6%). That works out to 49 people per square mile of land. Its largest town, Astoria, has 9,838 residents, 24.0% of the total. Together its 5 incorporated places hold 65.0% of those residents; the other 35.0% live outside any of them. Reported testing is thin here: 55 tests over 2008 to 2017, or 1.3 for every 1,000 residents (2025 estimate), where Oregon as a whole comes to 5.6.
From Astoria to Cannon Beach, CDC publishes no figure by town: each reads Clatsop County's.
| Place | Residents | Since 2020 | Share of residents |
|---|---|---|---|
| Astoria | 9,838 | −3.4% | 24.0% |
| Seaside | 7,092 | −1.1% | 17.3% |
| Warrenton | 6,312 | +0.4% | 15.4% |
| Gearhart | 1,861 | +3.2% | 4.5% |
| Cannon Beach | 1,512 | −0.1% | 3.7% |
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).
Clatsop County, Homes
Homes in Clatsop County
Of Clatsop County's 23,251 homes, 68% are detached houses, against 63% across Oregon; 10% are in buildings of five or more homes. Half of its homes were built before 1975, close to Oregon's 1980: 37% date from before 1960 and 18% from 2000 or later. 62% 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 | Clatsop County | Oregon |
|---|---|---|
| Housing units | 23,251 | 1,838,631 |
| Detached houses | 68% | 63% |
| In buildings of 5 or more | 10% | 17% |
| Mobile homes | 6% | 8% |
| Built before 1960 | 37% | 23% |
| Built since 2000 | 18% | 24% |
| Middle year built | 1975 | 1980 |
| Owner-occupied | 62% | 63% |
Census Bureau, American Community Survey, 2019 to 2023: estimates from a sample of homes, looser for a small place. Shares by Radon411.