Short-term kit
RA400 short-term liquid scintillation radon test kit, lab fee included
- Lab fee included
Method: Liquid scintillation
In home: 48 to 96 hours
Locations and reports
Radon Levels in Skagit County, Washington
EPA puts Skagit County in Zone 3, its lowest radon zone, and only 21 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
Share at 4+ pCi/L
0.0%
19.1 pts below WA
- Skagit
- 0.0%
- Washington
- 19.1%
42 tests, 2017
Median result
0.2pCi/L
Below action level
- Skagit
- 0.2 pCi/L
- EPA
- 4.0 pCi/L
Midpoint of the tests, 2017
Tests reported
42
13th of 14 by tests
- Skagit
- 42
- Clark
- 1,229
Reported to CDC before any fix, 2017
EPA radon zone
Zone 3
Lower potential
- 1
- 2
- Zone 3
1 highest, 3 lowest
EPA predicts under 2 pCi/L indoors
Rank in Washington
14 of 14
Lowest quarter
- Skagit
- 0.0%
- Pend Oreille
- 59.4%
By share, of 14 with 30+ tests
Read a result for Skagit County
Starts at Skagit County's median, 0.2 pCi/L
EPA’s own thresholds; the figures are the area’s, never this home’s.
EPA’s reading of 0.2 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. Skagit County's median reported result, 2017.
The data
Skagit County, At a glance
Skagit County at a glance
Predicted: EPA radon zone
EPA Zone 3: lower predicted potential
USGS geologic potential: Low across 98% of the county's area
Predicted: EPA Map of Radon Zones
Measured: tests reported to CDC
Radon tests reported for Skagit County, 2020
| Year | Share of reported tests at or above 4 pCi/L |
|---|---|
| 2014 | 0.0% |
| 2015 | 6.7% |
| 2016 | 0.0% |
| 2017 | 0.0% |
| 2018 | 25.0% |
| 2019 | 15.4% |
| 2020 | 4.8% |
2020: 4.8%. Across these years the share ran from 0.0% to 25.0%. Each column counts radon tests reported to CDC that year, not homes.
What these figures count
Only 21 tests were reported to CDC for Skagit 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).
Skagit County, Compared
Skagit County radon figures, compared
Calculated by Radon411Only 0 of 42 radon tests reported for Skagit County in 2017 reached 4 pCi/L (0.0%). The median result, 0.2 pCi/L, sits below 2, well under EPA's 4 pCi/L action level, and the top reported result was 1.5 pCi/L.
The newest figure, in 2020, counts only 21 tests (4.8% at or above 4 pCi/L), too few to compare, so this reading uses the 42-test figure.
Across 36 Washington counties pooled together, 19.1% of tests reached that level, so Skagit County runs 19.1 points below its state. Against the national pool of 31.7%, the gap is 31.7 points lower. Its place in the state: 14th of 14 Washington counties with 30 or more tests for the same period.
Zone 3 on EPA's map (predicted average under 2 pCi/L) and a 0.0% share point the same way here. Of 2 neighbours with a figure, all 2 reported a larger share at or above 4 pCi/L; the spread is 1.1% (Snohomish County) to 7.2% (Whatcom County).
Below the action level, 42 tests (100.0%) came in under 2 pCi/L, against 66.3% statewide, and 0 tests (0.0%) fell between 2 and 4, against 14.6% statewide. USGS geology rates 98% of the county's land low radon potential.
The busiest year on file was 2017, with 42 tests reported; the quietest, 2018, had 4.
Pooled shares: Radon411's sum of CDC's county counts for one period.
Skagit County, Geology
The ground under Skagit County
PredictedUSGS's geologic map puts all of Skagit County's mapped land in one class: low radon potential. The map puts 82.8% of Skagit County in the area it calls Cascade Mountains and 15.7% in Puget Lowlands. USGS gives both 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 |
|---|---|---|---|---|
| Cascade Mountains | Northern Cascade Mountains are Mesozoic metamorphic rocks intruded by Mesozoic and Tertiary granitic rocks. Southern Cascade Mountains are composed primarily of Tertiary and Holocene volcanic rocks. | Low | 6 | 82.8% |
| Puget Lowlands | Continental and marine sediments overlain by sandy and silty glacial deposits. | Low | 6 | 15.7% |
Names, descriptions and indexes: U.S. Geological Survey, Geologic Radon Potential Map (2025). Shares: Radon411, from the map cut to the boundary.
Skagit County beside the ground around it
Across Washington 13.7% of the land is rated high; none of Skagit County's is. Of the 4 counties that border it, 1 has more high-potential ground, Okanogan County the most at 38.7%.
The map rates the ground, not the air in any home.
Local help
Skagit County, Local resources
Radon testing and mitigation in Skagit 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
Skagit County, Questions
Questions about radon in Skagit County
Are radon levels high in Skagit County?
In 2020, 4.8% of the radon tests reported to CDC for Skagit County, Washington were at or above 4 pCi/L, and the median reported pre-mitigation result was 0.5 pCi/L. Of 14 Washington counties with 30 or more tests for the same period, 13 reported a higher share; pooled, the state comes to 19.1%.
Which counties border Skagit County?
Skagit County borders 4 counties: Whatcom County, Snohomish County, Chelan County and Okanogan County.
Products
Skagit County, Products
Testing a home in Skagit County
In Skagit County, 0.0% of 42 tests reported to CDC in 2017 reached 4 pCi/L, against 19.1% pooled across Washington. 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 Skagit County.
Test kits and monitors3
See every kit and monitor
Long-term kit
RL416 long-term radon test kit, lab fee included
- Lab fee included
Method: Alpha track
In home: 90 days to 12 months
Monitor
Wave Radon battery smart radon monitor
- C-NRPP 2024/25: Not included
- Battery
- Bluetooth
- App only
Method: Alpha spectrometry
- See every kit and monitor Test kits and monitors
Test kits and monitors: 1 of 3
Explore
Skagit County, Bordering counties
Counties bordering Skagit County
Calculated by Radon411- Radon levels in Chelan CountyEPA zone 3
20.7%at or above 4 pCi/L
Median 1.6 pCi/L · 29 tests · 20.7 points above Skagit County
- Radon levels in Okanogan CountyEPA zone 1
12.5%at or above 4 pCi/L
Median 2.6 pCi/L · 16 tests · 12.5 points above Skagit County
- Radon levels in Whatcom CountyEPA zone 3
7.2%at or above 4 pCi/L
Median 0.1 pCi/L · 69 tests · 7.2 points above Skagit County
- Radon levels in Snohomish CountyEPA zone 3
1.1%at or above 4 pCi/L
Median 0.2 pCi/L · 185 tests · 1.1 points above Skagit County
Skagit County, Cities and towns
Cities and towns in Skagit County
The Census Bureau estimates 132,975 residents in Skagit County for July 1, 2025, 3,090 more than in 2020 (+2.4%). That works out to 77 people per square mile of land. Its largest town, Mount Vernon, has 35,193 residents, 26.5% of the total. Together its 8 incorporated places hold 60.5% of those residents; the other 39.5% live outside any of them. Reported testing is thin here: 42 tests over 2017, or 0.3 for every 1,000 residents (2025 estimate), where Washington as a whole comes to 0.5.
From Mount Vernon to Hamilton, CDC publishes no figure by town: each reads Skagit County's.
| Place | Residents | Since 2020 | Share of residents |
|---|---|---|---|
| Mount Vernon | 35,193 | −0.3% | 26.5% |
| Anacortes | 18,080 | +2.3% | 13.6% |
| Sedro-Woolley | 13,308 | +6.6% | 10.0% |
| Burlington | 11,356 | +22.9% | 8.5% |
| La Conner | 991 | +2.0% | 0.7% |
| Concrete | 822 | +3.0% | 0.6% |
| Lyman | 431 | +0.9% | 0.3% |
| Hamilton | 289 | −2.7% | 0.2% |
8 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).
Skagit County, Homes
Homes in Skagit County
Of Skagit County's 56,472 homes, 74% are detached houses, against 62% across Washington; 10% are in buildings of five or more homes. Half of its homes were built before 1985, close to Washington's 1984: 22% date from before 1960 and 27% from 2000 or later. 71% 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 | Skagit County | Washington |
|---|---|---|
| Housing units | 56,472 | 3,262,667 |
| Detached houses | 74% | 62% |
| In buildings of 5 or more | 10% | 22% |
| Mobile homes | 7% | 6% |
| Built before 1960 | 22% | 21% |
| Built since 2000 | 27% | 28% |
| Middle year built | 1985 | 1984 |
| Owner-occupied | 71% | 64% |
Census Bureau, American Community Survey, 2019 to 2023: estimates from a sample of homes, looser for a small place. Shares by Radon411.