Short-term kit
Air Chek Short-Term radon test kit you hang, lab fee included
- Lab fee included
In home: 72 to 168 hours
Locations and reports
Radon Levels in Kitsap County, Washington
EPA puts Kitsap County in Zone 3, its lowest radon zone, and most reported tests there come back low, though 0.0% of 50 (2020) reached 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
0.0%
19.0 pts below WA
- Kitsap
- 0.0%
- Washington
- 19.0%
50 tests, 2020
Median result
0.4pCi/L
Below action level
- Kitsap
- 0.4 pCi/L
- EPA
- 4.0 pCi/L
Midpoint of the tests, 2020
Tests reported
50
7th of 10 by tests
- Kitsap
- 50
- Spokane
- 721
Reported to CDC before any fix, 2020
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
10 of 10
Lowest quarter
- Kitsap
- 0.0%
- Spokane
- 40.6%
By share, of 10 with 30+ tests
Read a result for Kitsap County
Starts at Kitsap County's median, 0.4 pCi/L
EPA’s own thresholds; the figures are the area’s, never this home’s.
EPA’s reading of 0.4 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. Kitsap County's median reported result, 2020.
The data
Kitsap County, At a glance
Kitsap County at a glance
Predicted: EPA radon zone
EPA Zone 3: lower predicted potential
USGS geologic potential: Low across 85% of the county's area
Predicted: EPA Map of Radon Zones
Measured: tests reported to CDC
Radon tests reported for Kitsap County, 2020
| Year | Share of reported tests at or above 4 pCi/L |
|---|---|
| 2014 | 0.0% |
| 2015 | 2.4% |
| 2016 | 2.6% |
| 2017 | 2.0% |
| 2018 | 0.0% |
| 2019 | 0.0% |
| 2020 | 0.0% |
2020: 0.0%. Across these years the share ran from 0.0% to 2.6%. Each column counts radon tests reported to CDC that year, not homes.
What these figures count
These are the 50 tests reported to CDC for Kitsap County over 2020, 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: 2020. Measured data period: 2005 to 2020 (every CDC figure on file).
Kitsap County, Compared
Kitsap County radon figures, compared
Calculated by Radon411Only 0 of 50 radon tests reported for Kitsap County in 2020 reached 4 pCi/L (0.0%). The median result, 0.4 pCi/L, sits below 2, well under EPA's 4 pCi/L action level, and the top reported result was 2.2 pCi/L.
Across 37 Washington counties pooled together, 19.0% of tests reached that level, so Kitsap County runs 19.0 points below its state. Against the national pool of 25.5%, the gap is 25.5 points lower. Its place in the state: 10th of 10 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. Pierce County, the one bordering county with a figure for the same period, reported 4.3%.
Below the action level, 48 tests (96.0%) came in under 2 pCi/L, against 67.6% statewide, and 2 tests (4.0%) fell between 2 and 4, against 13.3% statewide. Over 6 years of annual figures the share held within 2 points, from 0.0% in 2014 to 0.0% in 2020; its peak was 2.6% in 2016. USGS geology rates 85% of the county's land low radon potential.
The busiest year on file was 2015, with 83 tests reported; the quietest, 2018, had 10.
Kitsap CountyWashington, pooled
0.0% % of tests19.0% % of tests
| Year | Tests | Kitsap County, at or above 4 pCi/L | Washington, pooled |
|---|---|---|---|
| 2014 | 82 | 0.0% | 15.0% |
| 2015 | 83 | 2.4% | 17.4% |
| 2016 | 38 | 2.6% | 16.6% |
| 2017 | 50 | 2.0% | 19.1% |
| 2019 | 58 | 0.0% | 20.9% |
| 2020 | 50 | 0.0% | 19.0% |
Pooled shares: Radon411's sum of CDC's county counts for one period.
Kitsap County, Geology
The ground under Kitsap County
PredictedUSGS's geologic map puts all of Kitsap County's mapped land in one class: low radon potential. 85.1% of it lies in the area the map calls Puget Lowlands, 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 |
|---|---|---|---|---|
| Puget Lowlands | Continental and marine sediments overlain by sandy and silty glacial deposits. | Low | 6 | 85.1% |
Names, descriptions and indexes: U.S. Geological Survey, Geologic Radon Potential Map (2025). Shares: Radon411, from the map cut to the boundary.
Kitsap County beside the ground around it
Across Washington 13.7% of the land is rated high; none of Kitsap County's is. None of the 2 counties that border it has any moderate-potential ground either.
The map rates the ground, not the air in any home.
Local help
Kitsap County, Local resources
Radon testing and mitigation in Kitsap 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
Kitsap County, Questions
Questions about radon in Kitsap County
Are radon levels high in Kitsap County?
In 2020, 0.0% of the radon tests reported to CDC for Kitsap County, Washington were at or above 4 pCi/L, and the median reported pre-mitigation result was 0.4 pCi/L. Of 10 Washington counties with 30 or more tests for the same period, 9 reported a higher share; pooled, the state comes to 19.0%.
Which counties border Kitsap County?
Kitsap County borders 2 counties: Mason County and Pierce County.
Products
Kitsap County, Products
Testing a home in Kitsap County
In Kitsap County, 0.0% of 50 tests reported to CDC in 2020 reached 4 pCi/L, against 19.0% 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 Kitsap 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
MonitorX-Sense
XR0A-iR Wi-Fi battery radon detector with a screen
- C-NRPP 2024/25: Not included
- Battery
- Wi-Fi
- Screen, app
Method: Alpha spectrometry
First reading: Within 24 hours
- See every kit and monitor Test kits and monitors
Test kits and monitors: 1 of 3
Explore
Kitsap County, Bordering counties
Counties bordering Kitsap County
Calculated by Radon411- Radon levels in Pierce CountyEPA zone 3
4.3%at or above 4 pCi/L
Median 0.7 pCi/L · 420 tests · 4.3 points above Kitsap County
- Radon levels in Mason CountyEPA zone 3
0.0%at or above 4 pCi/L
Median 1.7 pCi/L · 3 tests · 0.0 points above Kitsap County
Kitsap County, Cities and towns
Cities and towns in Kitsap County
The Census Bureau estimates 283,374 residents in Kitsap County for July 1, 2025, 7,563 more than in 2020 (+2.7%). That works out to 717 people per square mile of land. No town dominates: Bremerton, the largest, has 45,482 residents, 16.1% of the total. Together its 4 incorporated places hold 36.3% of those residents; the other 63.7% live outside any of them. Reported testing is thin here: 50 tests over 2020, or 0.2 for every 1,000 residents (2025 estimate), where Washington as a whole comes to 0.3.
From Bremerton to Poulsbo, CDC publishes no figure by town: each reads Kitsap County's.
| Place | Residents | Since 2020 | Share of residents |
|---|---|---|---|
| Bremerton | 45,482 | +4.5% | 16.1% |
| Bainbridge Island | 24,691 | −0.6% | 8.7% |
| Port Orchard | 19,839 | +27.1% | 7.0% |
| Poulsbo | 12,749 | +6.6% | 4.5% |
4 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).
Kitsap County, Homes
Homes in Kitsap County
Of Kitsap County's 115,329 homes, 71% are detached houses, against 62% across Washington; 13% are in buildings of five or more homes. Half of its homes were built before 1986, close to Washington's 1984: 17% date from before 1960 and 24% from 2000 or later. 70% 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 | Kitsap County | Washington |
|---|---|---|
| Housing units | 115,329 | 3,262,667 |
| Detached houses | 71% | 62% |
| In buildings of 5 or more | 13% | 22% |
| Mobile homes | 6% | 6% |
| Built before 1960 | 17% | 21% |
| Built since 2000 | 24% | 28% |
| Middle year built | 1986 | 1984 |
| Owner-occupied | 70% | 64% |
Census Bureau, American Community Survey, 2019 to 2023: estimates from a sample of homes, looser for a small place. Shares by Radon411.