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 Franklin County, Washington
EPA puts Franklin County in Zone 2, its middle radon zone, and only 4 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
Highest bordering
22.4%
Whitman County
- Whitman
- 22.4%
- Walla Walla
- 16.4%
3 of 6 neighbours have 30+ tests, 2008 to 2017
Nearest county
16.4%
Walla Walla County, 29 miles
- Walla Walla
- 16.4%
- Washington
- 25.5%
Share at 4+ pCi/L, 122 tests, 2008 to 2017
Ground above low
100.0%
47.3 pts above Washington
- Franklin
- 100.0%
- Washington
- 52.7%
Share of land USGS rates moderate or high potential
Tests reported
19
Too few for a share
- Franklin
- 19
- Needed
- 30
2008 to 2017, laboratory
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 Franklin 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
Franklin County, At a glance
Franklin County at a glance
Predicted: EPA radon zone
EPA Zone 2: moderate predicted potential
Franklin 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 Franklin County, 2020
| Year | Share of reported tests at or above 4 pCi/L |
|---|---|
| 2014 | 12.5% |
| 2015 | 0.0% |
| 2016 | 12.5% |
| 2017 | 0.0% |
| 2018 | 0.0% |
| 2019 | 0.0% |
| 2020 | 25.0% |
2020: 25.0%. 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 4 tests were reported to CDC for Franklin 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).
Franklin County, Compared
Franklin County radon figures, compared
Calculated by Radon411CDC's largest figure for Franklin County rests on 19 tests over the 2008 to 2017 laboratory totals, 2 of them at or above 4 pCi/L, so each test moves its share by 5.3 points and no rank or comparison is drawn from it. Results reached as high as 4.4 pCi/L, with a middle value of 1.8 pCi/L.
Of the counties bordering it, 3 have a figure over the 2008 to 2017 laboratory totals: Whitman County reported the largest share at or above 4 pCi/L, 22.4%, and Walla Walla County the smallest, 16.4%, with Benton County at 19.5% between. Farther out, Yakima County (88 miles away) at 7.5%, Spokane County (103 miles away) at 41.4% and Chelan County (123 miles away) at 14.6% have figures too. 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 Franklin 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.
Franklin County, Geology
The ground under Franklin County
PredictedUSGS's geologic map puts all of Franklin County's mapped land in one class: moderate radon potential. All of it lies in the area the map calls Columbia Basin, to which USGS gives a radon index of 10, in the moderate band (9 to 11).
| Area | The rock, in USGS's words | Potential | Radon index | Share of land |
|---|---|---|---|---|
| Columbia Basin | Basaltic rocks low in uranium content. Uranium content of soils is moderately elevated. | Moderate | 10 | 100% |
Names, descriptions and indexes: U.S. Geological Survey, Geologic Radon Potential Map (2025). Shares: Radon411, from the map cut to the boundary.
Franklin County beside the ground around it
Across Washington 13.7% of the land is rated high; none of Franklin County's is. Of the 6 counties that border it, 2 have more high-potential ground, Whitman County the most at 0.9%.
The map rates the ground, not the air in any home.
Local help
Franklin County, Local resources
Radon testing and mitigation in Franklin 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
Franklin County, Questions
Questions about radon in Franklin County
Are radon levels high in Franklin County?
In 2020, 25.0% of the radon tests reported to CDC for Franklin County, Washington were at or above 4 pCi/L, and the median reported pre-mitigation result was 1.9 pCi/L. Of the counties bordering it, 3 have a figure over the 2008 to 2017 laboratory totals: Whitman County reported the largest share at or above 4 pCi/L, 22.4%, and Walla Walla County the smallest, 16.4%, with Benton County at 19.5% between.
Which counties border Franklin County?
Franklin County borders 6 counties: Walla Walla County, Benton County, Adams County, Columbia County, Grant County and Whitman County.
Products
Franklin County, Products
Testing a home in Franklin County
No CDC figure names Franklin County; the nearest county with one, Walla Walla County (29 miles away), reported 16.4% 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. In Zone 2 a short-term kit (2 to 90 days) is the quick first check in Franklin County; a long-term test tells the year-round average.
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
Hello Radon C battery radon monitor with an e-ink screen
- C-NRPP 2024/25: Not included
- Battery
- Screen
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
Franklin County, Bordering counties
Counties bordering Franklin County
Calculated by Radon411- Radon levels in Columbia CountyEPA zone 2
100.0%at or above 4 pCi/L
Median 6.6 pCi/L · 4 tests
- Radon levels in Grant CountyEPA zone 2
23.5%at or above 4 pCi/L
Median 2.7 pCi/L · 17 tests
- Radon levels in Whitman CountyEPA zone 2
22.4%at or above 4 pCi/L
Median 1.5 pCi/L · 58 tests
- Radon levels in Benton CountyEPA zone 2
19.5%at or above 4 pCi/L
Median 2.0 pCi/L · 113 tests
- Radon levels in Walla Walla CountyEPA zone 2
16.4%at or above 4 pCi/L
Median 1.4 pCi/L · 122 tests
- Radon levels in Adams CountyEPA zone 2
14.3%at or above 4 pCi/L
Median 1.5 pCi/L · 7 tests
Franklin County, Cities and towns
Cities and towns in Franklin County
Franklin County is growing: the Census Bureau puts it at 102,612 residents on July 1, 2025, up 5.6% from 97,137 in 2020. That works out to 83 people per square mile of land. Pasco alone is home to 82,848 of them, 80.7% of the total. Together its 4 incorporated places hold 86.2% of those residents; the other 13.8% live outside any of them. Reported testing is thin here: 19 tests over 2008 to 2017, or 0.2 for every 1,000 residents (2025 estimate), where Washington as a whole comes to 1.0.
From Pasco to Kahlotus, CDC publishes no figure by town: each reads Franklin County's.
| Place | Residents | Since 2020 | Share of residents |
|---|---|---|---|
| Pasco | 82,848 | +6.7% | 80.7% |
| Connell | 5,080 | −6.8% | 5.0% |
| Mesa | 391 | +1.0% | 0.4% |
| Kahlotus | 141 | −2.1% | 0.1% |
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).
Franklin County, Homes
Homes in Franklin County
Of Franklin County's 30,488 homes, 73% are detached houses, against 62% across Washington; 11% are in buildings of five or more homes. Much of Franklin County is recent building: 46% of its homes have gone up since 2000 and the middle year built is 1997, against 1984 for Washington. 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 | Franklin County | Washington |
|---|---|---|
| Housing units | 30,488 | 3,262,667 |
| Detached houses | 73% | 62% |
| In buildings of 5 or more | 11% | 22% |
| Mobile homes | 8% | 6% |
| Built before 1960 | 16% | 21% |
| Built since 2000 | 46% | 28% |
| Middle year built | 1997 | 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.