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Radon Levels in Seward County, Nebraska

EPA puts Seward County in Zone 1, its highest radon zone, and high results are common there: 77.3% of the 88 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

    77.3%

    39.1 pts above NE

    Seward
    77.3%
    Nebraska
    38.2%

    88 tests, 2023

  • Median result

    7.8pCi/L

    Action level reached

    Seward
    7.8 pCi/L
    EPA
    4.0 pCi/L

    Midpoint of the tests, 2023

  • Tests reported

    88

    16th of 33 by tests

    Seward
    88
    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

    3 of 33

    Top quarter

    Seward
    77.3%
    Gage
    79.8%

    By share, of 33 with 30+ tests

Read a result for Seward County

Starts at Seward County's median, 7.8 pCi/L

7.8pCi/L

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

EPA’s reading of 7.8 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. Seward County's median reported result, 2023.

Interpret this readingWhat a fix costs

The data

Seward County, At a glance

Seward County at a glance

Predicted: EPA radon zone

EPA Zone 1: highest predicted potential

EPA puts all of Seward 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 Seward County, 2023

Share of reported tests at or above 4 pCi/L, by year, Seward County
Share of reported tests at or above 4 pCi/L, by year, Seward County
YearShare of reported tests at or above 4 pCi/L
201454.7%
201561.5%
201660.0%
201767.4%
201866.1%
201962.2%
202066.0%
202160.8%
202275.6%
202377.3%

2023: 77.3%. Across these years the share ran from 54.7% to 77.3%. Each column counts radon tests reported to CDC that year, not homes.

What these figures count

These are the 88 tests reported to CDC for Seward 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

Seward County, Compared

Seward County radon figures, compared

Calculated by Radon411

More than half: 77.3% of the 88 radon tests reported to CDC for Seward County in 2023 read at least 4 pCi/L. That places it 3rd of 33 Nebraska counties with 30 or more tests for the same period. That is 39.1 points above the 38.2% pooled from 86 Nebraska counties.

The median result, 7.8 pCi/L, sits above EPA's 4 pCi/L action level, and the top reported result was 48.0 pCi/L. The rest split 6.8% under 2 pCi/L and 15.9% from 2 to 4 (Nebraska: 39.2% and 22.6%). Zone 1 on EPA's map (predicted average above 4 pCi/L) and a 77.3% share point the same way here.

No bordering county with a figure for the same period reported a higher share; the closest is Saunders County at 73.2%, the lowest Lancaster County at 26.7%. 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 2017, with 774 tests reported; the quietest, 2022, had 78.

Over 10 years of annual figures the share rose 22.6 points, from 54.7% in 2014 to 77.3% in 2023; its peak was 77.3% in 2023. Nationally, every county with a figure for the same period pools to 33.4%; Seward County sits 43.9 points above it. CDC also counts 62 tests taken after mitigation in Seward 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, Seward County against Nebraska2014 to 2023, years with 30 or more tests: Seward County 54.7% to 77.3%, the state's pooled share 38.2% in 2023.
Seward CountyNebraska, pooled
Share of reported tests at or above 4 pCi/L by year, Seward County against Nebraska: data table
YearTestsSeward County, at or above 4 pCi/LNebraska, pooled
201476254.7%50.5%
201565461.5%53.3%
201667560.0%47.4%
201777467.4%47.7%
201866366.1%44.5%
201951662.2%44.3%
202042366.0%42.2%
202130660.8%34.9%
20227875.6%34.0%
20238877.3%38.2%
Seward County against Nebraska, the United States and nearby counties, 2023
AreaTestsAt or above 4 pCi/LMedianDifference from Seward County
Seward County8877.3%7.8 pCi/LThis county
Nebraska, pooled86 counties, pooled11,16338.2%Not pooled−39.1 points
United States, pooled642 counties, pooled128,74033.4%Not pooled−43.9 points
Gage Countyhighest in the state8479.8%9.4 pCi/L+2.5 points
Dakota Countylowest in the state1303.1%0.4 pCi/L−74.2 points
Fillmore County, NEborders it9100.0%13.5 pCi/L+22.7 points
Polk County, NEborders it1894.4%7.0 pCi/L+17.1 points
Saunders County, NEborders it9773.2%6.2 pCi/L−4.1 points
York County, NEborders it6264.5%5.7 pCi/L−12.8 points
Butler County, NEborders it2356.5%7.0 pCi/L−20.8 points
Saline County, NEborders it2951.7%4.2 pCi/L−25.6 points
Lancaster County, NEborders it4,05826.7%1.6 pCi/L−50.6 points
Where Seward County's reported results fell, 2023, beside Nebraska and the United States
ResultSeward County testsSeward County shareNebraska shareU.S. shareAgainst Nebraska
Under 2 pCi/L66.8%39.2%41.4%−32.4 points
2 to 4 pCi/L1415.9%22.6%25.2%−6.7 points
4 pCi/L and above6877.3%38.2%33.4%+39.1 points
Seward 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
Seward County radon tests by year, against Nebraska's pooled share
YearTestsAt or above 4 pCi/LMedianHighestNebraska, pooledChange from the row before
20238877.3%7.8 pCi/L48.0 pCi/L38.2%+1.7 points
20227875.6%6.3 pCi/L18.4 pCi/L34.0%+14.8 points
202130660.8%5.9 pCi/L31.7 pCi/L34.9%−5.2 points
202042366.0%5.3 pCi/L87.0 pCi/L42.2%+3.8 points
201951662.2%5.0 pCi/L38.4 pCi/L44.3%−3.9 points
201866366.1%5.7 pCi/L48.3 pCi/L44.5%−1.3 points
201777467.4%6.2 pCi/L33.5 pCi/L47.7%+7.4 points
201667560.0%5.2 pCi/L56.7 pCi/L47.4%−1.5 points
201565461.5%5.0 pCi/L35.4 pCi/L53.3%+6.8 points
201476254.7%4.5 pCi/L29.4 pCi/L50.5%First on file

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

Seward County, Geology

The ground under Seward County

Predicted

USGS's geologic map puts all of Seward 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 Seward 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.

Seward County beside the ground around it

Seward County has more high-potential ground than Nebraska as a whole: 100% of its land against 40.9%. Of the 7 counties that border it, none has as large a share of high-potential ground; Fillmore County comes nearest at 100%.

Share of land by USGS radon potential: Seward County, the 7 counties bordering it and Nebraska
AreaEPA zoneLow potentialModerate potentialHigh potential
Seward CountyZone 1NoneNone100%
Saline CountyZone 1NoneNone100%
Butler CountyZone 1None0.1%99.9%
Lancaster CountyZone 1NoneNone100%
York CountyZone 1NoneNone100%
Polk CountyZone 1None26.1%73.9%
Fillmore CountyZone 1NoneNone100%
Saunders CountyZone 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

Seward County, Local resources

Radon testing and mitigation in Seward County

Listed radon businesses with an address in Seward County:

Listed radon professionals by town: Pleasant Dale

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

Seward County, Questions

Questions about radon in Seward County

Are radon levels high in Seward County?

In 2023, 77.3% of the radon tests reported to CDC for Seward County, Nebraska were at or above 4 pCi/L, and the median reported pre-mitigation result was 7.8 pCi/L. Of 33 Nebraska counties with 30 or more tests for the same period, 2 reported a higher share; pooled, the state comes to 38.2%.

Which counties border Seward County?

Seward County borders 7 counties: Saline County, Butler County, Lancaster County, York County, Polk County, Fillmore County and Saunders County.

Products

Seward County, Products

Testing a home in Seward County

In Seward County, 77.3% of 88 tests reported to CDC in 2023 reached 4 pCi/L, against 38.2% pooled across Nebraska. In Zone 1 the year-round level in Seward 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

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

Explore

Seward County, Bordering counties

Counties bordering Seward County

Calculated by Radon411

Seward County, Cities and towns

Cities and towns in Seward County

The Census Bureau estimates 18,032 residents in Seward County for July 1, 2025, 408 more than in 2020 (+2.3%). That works out to 32 people per square mile of land. Its largest town, Seward, has 7,892 residents, 43.8% of the total. Together its 10 incorporated places hold 69.2% of those residents; the other 30.8% live outside any of them. CDC's 88 reported tests for 2023 work out to 4.9 per 1,000 residents (2025 estimate), close to Nebraska's 5.5.

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

The cities and towns in Seward County by residents, July 1, 2025
PlaceResidentsSince 2020Share of residents
Seward7,892+2.5%43.8%
Milford2,286+6.1%12.7%
Utica831−0.7%4.6%
Beaver Crossing368−1.1%2.0%
Staplehurst229−3.4%1.3%
Pleasant Dale214−4.0%1.2%
Garland210Level1.2%
Goehner177−3.8%1.0%
Bee168−1.8%0.9%
Cordova100+4.2%0.6%

10 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).

Seward County, Homes

Homes in Seward County

Seward County is a place of houses on their own lots: 81% of its 7,138 homes are detached single-family houses, against 72% across Nebraska. Half of its homes were built before 1970, close to Nebraska's 1975: 39% date from before 1960 and 17% from 2000 or later. 72% of occupied homes are lived in by their owner (Nebraska: 67%); in the rest a tenant can run a test, but a fix is the landlord's to make.

Homes in Seward County, Nebraska, 2019 to 2023
HomesSeward CountyNebraska
Housing units7,138855,631
Detached houses81%72%
In buildings of 5 or more8%17%
Mobile homes2%3%
Built before 196039%32%
Built since 200017%22%
Middle year built19701975
Owner-occupied72%67%

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