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Radon Levels in Washington County, Nebraska

EPA puts Washington County in Zone 1, its highest radon zone, and high results are common there: 76.1% of the 71 radon tests reported to CDC (2023) came back at or above 4 pCi/L. Homes with elevated levels occur in all three zones, so only a test measures yours.

Data checked By Radon411Methodology

How to test this homeFind a certified tester

  • Share at 4+ pCi/L

    76.1%

    37.9 pts above NE

    Washington
    76.1%
    Nebraska
    38.2%

    71 tests, 2023

  • Median result

    6.5pCi/L

    Action level reached

    Washington
    6.5 pCi/L
    EPA
    4.0 pCi/L

    Midpoint of the tests, 2023

  • Tests reported

    71

    18th of 33 by tests

    Washington
    71
    Lancaster
    4,058

    Reported to CDC before any fix, 2023

  • EPA radon zone

    Zone 1

    Highest potential

    1. Zone 1
    2. 2
    3. 3

    1 highest, 3 lowest

    EPA predicts over 4 pCi/L indoors

  • Rank in Nebraska

    4 of 33

    Top quarter

    Washington
    76.1%
    Gage
    79.8%

    By share, of 33 with 30+ tests

Read a result for Washington County

Starts at Washington County's median, 6.5 pCi/L

6.5pCi/L

EPA’s own thresholds; the figures are the area’s, never this home’s.

EPA’s reading of 6.5 pCi/L

At or above 4 pCi/L

  1. Under 20 to 1.9 pCi/L
  2. 2 to 4consider a fix
  3. 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. Washington County's median reported result, 2023.

Interpret this readingWhat a fix costs

The data

Washington County, At a glance

Washington County at a glance

Predicted: EPA radon zone

EPA Zone 1: highest predicted potential

EPA puts all of Washington County in and predicts an average indoor of greater than 4 pCi/L (greater than 150 Bq/m³) across the county. That is one forecast for the whole county, not a reading of any address in it; homes above EPA's turn up in all three zones.

USGS geologic potential: High across 100% of the county's area

Predicted: EPA Map of Radon Zones

Measured: tests reported to CDC

Radon tests reported for Washington County, 2023

Share of reported tests at or above 4 pCi/L, by year, Washington County
Share of reported tests at or above 4 pCi/L, by year, Washington County
YearShare of reported tests at or above 4 pCi/L
201450.5%
201572.1%
201661.3%
201762.1%
201863.0%
201965.2%
202063.3%
202156.9%
202269.6%
202376.1%

2023: 76.1%. Across these years the share ran from 50.5% to 76.1%. Each column counts radon tests reported to CDC that year, not homes.

What these figures count

These are the 71 tests reported to CDC for Washington County over 2023, 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: 2023. Measured data period: 2005 to 2023 (every CDC figure on file).

How to read these figures

Washington County, Compared

Washington County radon figures, compared

Calculated by Radon411

More than half: 76.1% of the 71 radon tests reported to CDC for Washington County in 2023 read at least 4 pCi/L. That places it 4th of 33 Nebraska counties with 30 or more tests for the same period. That is 37.9 points above the 38.2% pooled from 86 Nebraska counties.

The median result, 6.5 pCi/L, sits above EPA's 4 pCi/L action level, and the top reported result was 31.2 pCi/L. The rest split 7.0% under 2 pCi/L and 16.9% from 2 to 4 (Nebraska: 39.2% and 22.6%). Zone 1 on EPA's map (predicted average above 4 pCi/L) and a 76.1% share point the same way here.

No bordering county with a figure for the same period reported a higher share; the closest is Dodge County at 62.1%, the lowest Douglas County at 38.7%. Statewide for the same period, Gage County reported the highest share (79.8%) and Dakota County the lowest (3.1%).

The busiest year on file was 2016, with 1,203 tests reported; the quietest, 2023, had 71.

Over 10 years of annual figures the share rose 25.6 points, from 50.5% in 2014 to 76.1% in 2023; its peak was 76.1% in 2023. Nationally, every county with a figure for the same period pools to 33.4%; Washington County sits 42.7 points above it. CDC also counts 46 tests taken after mitigation in Washington County for the same period: tests in homes where a fix was already in.

Share of reported tests at or above 4 pCi/L by year, Washington County against Nebraska2014 to 2023, years with 30 or more tests: Washington County 50.5% to 76.1%, the state's pooled share 38.2% in 2023.
Washington CountyNebraska, pooled
Share of reported tests at or above 4 pCi/L by year, Washington County against Nebraska: data table
YearTestsWashington County, at or above 4 pCi/LNebraska, pooled
201458850.5%50.5%
201586172.1%53.3%
20161,20361.3%47.4%
201783162.1%47.7%
201863363.0%44.5%
201955265.2%44.3%
202044163.3%42.2%
202130656.9%34.9%
20227969.6%34.0%
20237176.1%38.2%
Washington County against Nebraska, the United States and nearby counties, 2023
AreaTestsAt or above 4 pCi/LMedianDifference from Washington County
Washington County7176.1%6.5 pCi/LThis county
Nebraska, pooled86 counties, pooled11,16338.2%Not pooled−37.9 points
United States, pooled642 counties, pooled128,74033.4%Not pooled−42.7 points
Gage Countyhighest in the state8479.8%9.4 pCi/L+3.7 points
Dakota Countylowest in the state1303.1%0.4 pCi/L−73.0 points
Burt County, NEborders it2491.7%9.0 pCi/L+15.6 points
Dodge County, NEborders it11662.1%5.0 pCi/L−14.0 points
Douglas County, NEborders it2,75438.7%2.9 pCi/L−37.4 points
Where Washington County's reported results fell, 2023, beside Nebraska and the United States
ResultWashington County testsWashington County shareNebraska shareU.S. shareAgainst Nebraska
Under 2 pCi/L57.0%39.2%41.4%−32.2 points
2 to 4 pCi/L1216.9%22.6%25.2%−5.7 points
4 pCi/L and above5476.1%38.2%33.4%+37.9 points
Washington County ranked among the 33 Nebraska counties with 30 or more tests, by share at or above 4 pCi/L, 2023
CountyRankTestsAt or above 4 pCi/LMedian
Gage County1 of 338479.8%9.4 pCi/L
Cedar County2 of 335078.0%6.8 pCi/L
Seward County3 of 338877.3%7.8 pCi/L
Washington County4 of 337176.1%6.5 pCi/L
Wayne County5 of 334374.4%6.9 pCi/L
Saunders County6 of 339773.2%6.2 pCi/L
Cuming County7 of 333770.3%6.8 pCi/L
Stanton County8 of 333268.8%7.8 pCi/L
Cass County9 of 3311168.5%5.5 pCi/L
Madison County10 of 3321366.7%5.8 pCi/L
Adams County11 of 3315566.5%4.8 pCi/L
Washington County radon tests by year, against Nebraska's pooled share
YearTestsAt or above 4 pCi/LMedianHighestNebraska, pooledChange from the row before
20237176.1%6.5 pCi/L31.2 pCi/L38.2%+6.5 points
20227969.6%5.3 pCi/L19.8 pCi/L34.0%+12.7 points
202130656.9%4.7 pCi/L29.1 pCi/L34.9%−6.4 points
202044163.3%5.2 pCi/L21.4 pCi/L42.2%−1.9 points
201955265.2%5.8 pCi/L43.1 pCi/L44.3%+2.2 points
201863363.0%5.3 pCi/L68.0 pCi/L44.5%+0.9 points
201783162.1%4.9 pCi/L39.4 pCi/L47.7%+0.8 points
20161,20361.3%5.1 pCi/L34.4 pCi/L47.4%−10.8 points
201586172.1%6.5 pCi/L41.3 pCi/L53.3%+21.6 points
201458850.5%4.0 pCi/L34.8 pCi/L50.5%First on file

Pooled shares: Radon411's sum of CDC's county counts for one period.

Washington County, Geology

The ground under Washington County

Predicted

USGS's geologic map puts all of Washington County's mapped land in one class: high radon potential. All of it lies in the area the map calls Pre-Wisconsin glacial deposits, to which USGS gives a radon index of 13, in the high band (12 to 17).

USGS's geologic areas under Washington County
AreaThe rock, in USGS's wordsPotentialRadon indexShare of land
Pre-Wisconsin glacial depositsLoess-mantled glacial drift.High13100%

Names, descriptions and indexes: U.S. Geological Survey, Geologic Radon Potential Map (2025). Shares: Radon411, from the map cut to the boundary.

Washington County beside the ground around it

Washington County has more high-potential ground than Nebraska as a whole: 100% of its land against 40.9%. Of the 5 counties that border it, none has as large a share of high-potential ground; Dodge County comes nearest at 100%.

Share of land by USGS radon potential: Washington County, the 5 counties bordering it and Nebraska
AreaEPA zoneLow potentialModerate potentialHigh potential
Washington CountyZone 1NoneNone100%
Douglas CountyZone 1NoneNone100%
Burt CountyZone 1NoneNone100%
Dodge CountyZone 1NoneNone100%
Harrison County, IAZone 1NoneNone100%
Pottawattamie County, IAZone 1NoneNone100%
Nebraska93 counties, pooled by land areaVaries28.2%30.9%40.9%

The map rates the ground, not the air in any home.

Local help

Washington County, Local resources

Radon testing and mitigation in Washington County

Listed radon businesses with an address in Washington County:

Listed radon professionals by town: Blair

What Nebraska's program says
Phone
(402) 471-1005
Licensing of radon professionals
If radon testing is done in schools, offices, or other places of work, it must be done by a licensed radon measurement business.

What it means

Washington County, Questions

Questions about radon in Washington County

Are radon levels high in Washington County?

In 2023, 76.1% of the radon tests reported to CDC for Washington County, Nebraska were at or above 4 pCi/L, and the median reported pre-mitigation result was 6.5 pCi/L. Of 33 Nebraska counties with 30 or more tests for the same period, 3 reported a higher share; pooled, the state comes to 38.2%.

Which counties border Washington County?

Washington County borders 5 counties: Douglas County, NE, Burt County, NE, Dodge County, NE, Harrison County, IA and Pottawattamie County, IA.

Products

Washington County, Products

Testing a home in Washington County

In Washington County, 76.1% of 71 tests reported to CDC in 2023 reached 4 pCi/L, against 38.2% pooled across Nebraska. In Zone 1 the year-round level in Washington County is the one to know: a long-term test (more than 90 days) or a monitor, with a short-term kit for a first answer.

Test kits and monitors3

See every kit and monitor

Washington County is in EPA Zone 1, the highest predicted radon potential. Best radon monitors for Zone 1 counties like Washington County

Explore

Washington County, Bordering counties

Counties bordering Washington County

Calculated by Radon411

Washington County, Cities and towns

Cities and towns in Washington County

The Census Bureau estimates 21,302 residents in Washington County for July 1, 2025, 370 more than in 2020 (+1.8%). That works out to 55 people per square mile of land. Its largest town, Blair, has 7,997 residents, 37.5% of the total. Together its 6 incorporated places hold 52.4% of those residents; the other 47.6% live outside any of them. Reported testing is thin here: 71 tests over 2023, or 3.3 for every 1,000 residents (2025 estimate), where Nebraska as a whole comes to 5.5.

From Blair to Washington, CDC publishes no figure by town: each reads Washington County's.

The cities and towns in Washington County by residents, July 1, 2025
PlaceResidentsSince 2020Share of residents
Blair7,997+2.2%37.5%
Arlington1,329+1.6%6.2%
Fort Calhoun1,108+1.6%5.2%
Kennard370−2.4%1.7%
Herman217−3.1%1.0%
Washington131+1.6%0.6%

6 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).

Washington County, Homes

Homes in Washington County

Washington County is a place of houses on their own lots: 84% of its 8,665 homes are detached single-family houses, against 72% across Nebraska. Half of its homes were built before 1978, close to Nebraska's 1975: 31% date from before 1960 and 20% from 2000 or later. Owners live in 82% of the occupied homes (Nebraska: 67%), so for most households a test and a fix are their own to order.

Homes in Washington County, Nebraska, 2019 to 2023
HomesWashington CountyNebraska
Housing units8,665855,631
Detached houses84%72%
In buildings of 5 or more8%17%
Mobile homes3%3%
Built before 196031%32%
Built since 200020%22%
Middle year built19781975
Owner-occupied82%67%

Census Bureau, American Community Survey, 2019 to 2023: estimates from a sample of homes, looser for a small place. Shares by Radon411.