Short-term kit
Radon Short Term Test Kit short-term charcoal radon test kit, lab fee included
- Lab fee included
Method: Charcoal
In home: 2 to 7 days
Locations and reports
Radon Levels in Clallam County, Washington
EPA puts Clallam County in Zone 3, its lowest radon zone, and only 12 radon tests from it are on file with CDC (2020). Homes with elevated levels occur in all three zones, so only a test measures yours.
Data checked By Radon411Methodology
Nearest county
4.9%
Kitsap County, 66 miles
- Kitsap
- 4.9%
- Washington
- 25.5%
Share at 4+ pCi/L, 82 tests, 2008 to 2017
Ground above low
None
52.7 pts below Washington
- Clallam
- 0.0%
- Washington
- 52.7%
Share of land USGS rates moderate or high potential
Tests reported
22
Too few for a share
- Clallam
- 22
- Needed
- 30
2019
EPA radon zone
Zone 3
Lower potential
- 1
- 2
- Zone 3
1 highest, 3 lowest
EPA predicts under 2 pCi/L indoors
Read a result for Clallam 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
Clallam County, At a glance
Clallam County at a glance
Predicted: EPA radon zone
EPA Zone 3: lower predicted potential
USGS geologic potential: Low across 99% of the county's area
Predicted: EPA Map of Radon Zones
Measured: tests reported to CDC
Radon tests reported for Clallam County, 2020
| Year | Share of reported tests at or above 4 pCi/L |
|---|---|
| 2014 | 12.5% |
| 2015 | 26.3% |
| 2016 | 28.6% |
| 2017 | 0.0% |
| 2018 | 0.0% |
| 2019 | 9.1% |
| 2020 | 8.3% |
2020: 8.3%. Across these years the share ran from 0.0% to 28.6%. Each column counts radon tests reported to CDC that year, not homes.
What these figures count
Only 12 tests were reported to CDC for Clallam County over 2020, 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: 2020. Measured data period: 2005 to 2020 (every CDC figure on file).
Clallam County, Compared
Clallam County radon figures, compared
Calculated by Radon411CDC's largest figure for Clallam County rests on 22 tests in 2019, 2 of them at or above 4 pCi/L, so each test moves its share by 4.5 points and no rank or comparison is drawn from it. Results reached as high as 7.1 pCi/L, with a middle value of 0.6 pCi/L.
The nearest counties with a figure are Kitsap County (66 miles away) at 4.9%, Thurston County (93 miles away) at 10.1% and Snohomish County (103 miles away) at 2.3%. Pooled across 39 Washington counties, 25.5% of reported tests reached that level; across every county in the country with a figure, 35.7%.
Statewide for the same period, Pend Oreille County reported the highest share (63.2%) and Snohomish County the lowest (2.3%). EPA's 1993 map puts Clallam County in Zone 3, its lowest label: a predicted county average under 2 pCi/L. USGS geology rates 99% of the county's land low radon potential.
Pooled shares: Radon411's sum of CDC's county counts for one period.
Clallam County, Geology
The ground under Clallam County
PredictedUSGS's geologic map puts all of Clallam County's mapped land in one class: low radon potential. 99.5% of it lies in the area the map calls Coastal Mountains, to which USGS gives a radon index of 6, in the low band (5 to 8).
| Area | The rock, in USGS's words | Potential | Radon index | Share of land |
|---|---|---|---|---|
| Coastal Mountains | Cretaceous and Tertiary continental and marine sedimentary rocks and pre-Miocene volcanic rocks. | Low | 6 | 99.5% |
Names, descriptions and indexes: U.S. Geological Survey, Geologic Radon Potential Map (2025). Shares: Radon411, from the map cut to the boundary.
Clallam County beside the ground around it
Across Washington 13.7% of the land is rated high; none of Clallam County's is. None of the one county that borders it has any moderate-potential ground either.
The map rates the ground, not the air in any home.
Local help
Clallam County, Local resources
Radon testing and mitigation in Clallam County
- Radon ProgramRadon Program, run by Washington State Department of Health, offers free or discounted test kits, and answers questions about testing and mitigation in Washington.Visit the program’s page(opens in a new tab)
- Free and low-cost kitsThe program says:
We have a limited supply of free radon test kits.
- Compare kits
- See the Washington directoryNo professionals are listed in Washington yet. The state program can point you to registered testers and mitigators.
What Washington's program says
- Phone
- 360-236-3200
- doh.radon@doh.wa.gov
What it means
Clallam County, Questions
Questions about radon in Clallam County
Are radon levels high in Clallam County?
In 2020, 8.3% of the radon tests reported to CDC for Clallam County, Washington were at or above 4 pCi/L, and the median reported pre-mitigation result was 0.6 pCi/L. Of the 8 nearest counties with a figure, within 141 miles, the share of tests at or above 4 pCi/L runs from 2.3% to 11.3%.
Which counties border Clallam County?
Clallam County borders 1 county: Jefferson County.
Products
Clallam County, Products
Testing a home in Clallam County
No CDC figure names Clallam County; the nearest county with one, Kitsap County (66 miles away), reported 4.9% of its tests at or above 4 pCi/L over the 2008 to 2017 laboratory totals, the only reading nearby until a test of this home. 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 Clallam 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
Monitor
EcoBlu plug-in digital radon monitor with a display
- C-NRPP 2024/25: Not included
- Plug-in
- Alarm
- Screen
Method: Ion chamber
First reading: Within 10 minutes
- See every kit and monitor Test kits and monitors
Test kits and monitors: 1 of 3
Explore
Clallam County, Bordering counties
Counties bordering Clallam County
Calculated by Radon411- Radon levels in Jefferson CountyEPA zone 3
9.1%at or above 4 pCi/L
Median 1.0 pCi/L · 22 tests
Clallam County, Cities and towns
Cities and towns in Clallam County
The Census Bureau estimates 78,202 residents in Clallam County for July 1, 2025, 846 more than in 2020 (+1.1%). That works out to 45 people per square mile of land. Its largest town, Port Angeles, has 20,146 residents, 25.8% of the total. Together its 3 incorporated places hold 40.7% of those residents; the other 59.3% live outside any of them. Reported testing is thin here: 22 tests over 2019, or 0.3 for every 1,000 residents (2025 estimate), where Washington as a whole comes to 0.5.
From Port Angeles to Forks, CDC publishes no figure by town: each reads Clallam County's.
| Place | Residents | Since 2020 | Share of residents |
|---|---|---|---|
| Port Angeles | 20,146 | +0.7% | 25.8% |
| Sequim | 8,215 | +1.8% | 10.5% |
| Forks | 3,488 | +2.6% | 4.5% |
3 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).
Clallam County, Homes
Homes in Clallam County
Of Clallam County's 38,295 homes, 71% are detached houses, against 62% across Washington; 13% are mobile homes. Half of its homes were built before 1982, close to Washington's 1984: 20% date from before 1960 and 23% from 2000 or later. 73% of occupied homes are lived in by their owner (Washington: 64%); in the rest a tenant can run a test, but a fix is the landlord's to make.
| Homes | Clallam County | Washington |
|---|---|---|
| Housing units | 38,295 | 3,262,667 |
| Detached houses | 71% | 62% |
| In buildings of 5 or more | 9% | 22% |
| Mobile homes | 13% | 6% |
| Built before 1960 | 20% | 21% |
| Built since 2000 | 23% | 28% |
| Middle year built | 1982 | 1984 |
| Owner-occupied | 73% | 64% |
Census Bureau, American Community Survey, 2019 to 2023: estimates from a sample of homes, looser for a small place. Shares by Radon411.