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Radon Levels in Sac County, Iowa

EPA puts Sac County in Zone 1, its highest radon zone, and high results are common there: 76.6% of the 491 radon tests reported to CDC (2008 to 2017, laboratory totals) 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

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  • Share at 4+ pCi/L

    76.6%

    18.1 pts above IA

    Sac
    76.6%
    Iowa
    58.5%

    491 tests, 2008 to 2017

  • Median result

    7.0pCi/L

    Action level reached

    Sac
    7.0 pCi/L
    EPA
    4.0 pCi/L

    Midpoint of the tests, 2008 to 2017

  • Tests reported

    491

    50th of 99 by tests

    Sac
    491
    Polk
    10,945

    Reported to CDC before any fix, 2008 to 2017

  • 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 Iowa

    10 of 99

    Top quarter

    Sac
    76.6%
    Sioux
    84.2%

    By share, of 99 with 30+ tests

Read a result for Sac County

Starts at Sac County's median, 7.0 pCi/L

7.0pCi/L

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

EPA’s reading of 7.0 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. Sac County's median reported result, 2008 to 2017.

Interpret this readingWhat a fix costs

The data

Sac County, At a glance

Sac County at a glance

Predicted: EPA radon zone

EPA Zone 1: highest predicted potential

EPA puts all of Sac 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 Sac County, 2008 to 2017, laboratory

Reported results by concentration band, Sac County, 2008 to 2017, laboratory
Under 2 pCi/L: 11%2 to 4 pCi/L: 12%4 pCi/L and above: 77%

Of 491 pre-mitigation tests reported to CDC, not homes in this area.

Reported results by concentration band, Sac County, 2008 to 2017, laboratory: data table
Result bandTests MeasuredShare Measured
Under 2 pCi/L5411.0%
2 to 4 pCi/L6112.4%
4 pCi/L and above37676.6%
What these figures count

These are the 491 tests reported to CDC for Sac County over 2008 to 2017 (laboratory totals), 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: 2008 to 2017, laboratory. Measured data period: 2005 to 2017 (every CDC figure on file).

How to read these figures

Sac County, Compared

Sac County radon figures, compared

Calculated by Radon411

More than half: 76.6% of the 491 radon tests reported to CDC for Sac County over the 2008 to 2017 laboratory totals read at least 4 pCi/L. That places it 10th of 99 Iowa counties with 30 or more tests for the same period. That is 18.1 points above the 58.5% pooled from 99 Iowa counties.

The median result, 7.0 pCi/L, sits above EPA's 4 pCi/L action level, and the top reported result was 113.3 pCi/L. The rest split 11.0% under 2 pCi/L and 12.4% from 2 to 4 (Iowa: 21.8% and 19.7%). Zone 1 on EPA's map (predicted average above 4 pCi/L) and a 76.6% share point the same way here.

1 of its 7 bordering counties with figures ran higher, led by Carroll County at 77.6%; Pocahontas County reported 68.8%. Statewide for the same period, Sioux County reported the highest share (84.2%) and Decatur County the lowest (25.9%).

CDC's ten-year totals for Sac County went from 263 tests (2005 to 2014) to 491 (2008 to 2017), the share going from 81.4% to 76.6%.

Nationally, every county with a figure for the same period pools to 35.7%; Sac County sits 40.9 points above it. CDC also counts 15 tests taken after mitigation in Sac County for the same period: tests in homes where a fix was already in.

Sac County against Iowa, the United States and nearby counties, 2008 to 2017, laboratory
AreaTestsAt or above 4 pCi/LMedianDifference from Sac County
Sac County49176.6%7.0 pCi/LThis county
Iowa, pooled99 counties, pooled95,24558.5%Not pooled−18.1 points
United States, pooled2,661 counties, pooled2,013,54435.7%Not pooled−40.9 points
Sioux Countyhighest in the state1,98284.2%10.7 pCi/L+7.6 points
Decatur Countylowest in the state8525.9%2.5 pCi/L−50.7 points
Carroll County, IAborders it59477.6%7.8 pCi/L+1.0 points
Crawford County, IAborders it37374.8%7.0 pCi/L−1.8 points
Cherokee County, IAborders it79574.5%7.6 pCi/L−2.1 points
Buena Vista County, IAborders it68872.1%6.9 pCi/L−4.5 points
Ida County, IAborders it39971.7%7.4 pCi/L−4.9 points
Calhoun County, IAborders it50769.8%6.1 pCi/L−6.8 points
Pocahontas County, IAborders it41768.8%6.4 pCi/L−7.8 points
Where Sac County's reported results fell, 2008 to 2017, laboratory, beside Iowa and the United States
ResultSac County testsSac County shareIowa shareU.S. shareAgainst Iowa
Under 2 pCi/L5411.0%21.8%39.6%−10.8 points
2 to 4 pCi/L6112.4%19.7%24.7%−7.3 points
4 pCi/L and above37676.6%58.5%35.7%+18.1 points
Sac County ranked among the 99 Iowa counties with 30 or more tests, by share at or above 4 pCi/L, 2008 to 2017, laboratory
CountyRankTestsAt or above 4 pCi/LMedian
Shelby County5 of 9985778.4%9.0 pCi/L
Audubon County6 of 9918978.3%9.5 pCi/L
Lyon County7 of 9923777.6%8.3 pCi/L
Carroll County8 of 9959477.6%7.8 pCi/L
Cass County9 of 9932777.4%8.1 pCi/L
Sac County10 of 9949176.6%7.0 pCi/L
Crawford County11 of 9937374.8%7.0 pCi/L
Monona County12 of 9960374.6%7.0 pCi/L
Cherokee County13 of 9979574.5%7.6 pCi/L
Franklin County14 of 9931373.5%6.2 pCi/L
Jasper County15 of 9974673.3%8.2 pCi/L
Sac County ten-year laboratory totals, against Iowa's pooled share
PeriodTestsAt or above 4 pCi/LMedianHighestIowa, pooledChange from the row before
2008 to 201749176.6%7.0 pCi/L113.3 pCi/L58.5%−1.6 points
2007 to 201641778.2%7.0 pCi/L113.3 pCi/L58.6%−1.0 points
2006 to 201534279.2%7.2 pCi/L113.3 pCi/L59.4%−2.2 points
2005 to 201426381.4%7.8 pCi/L55.1 pCi/L59.6%First on file

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

Sac County, Geology

The ground under Sac County

Predicted

USGS's geologic map puts all of Sac County's mapped land in one class: high radon potential. The map puts 66.1% of Sac County in the area it calls Des Moines Lobe and 33.9% in Loess-Covered Drift Plains. USGS gives the first a radon index of 12 and the second 13, both in the high band (12 to 17).

USGS's geologic areas under Sac County
AreaThe rock, in USGS's wordsPotentialRadon indexShare of land
Des Moines LobeCalcareous loamy till derived from shale, limestone, dolomite, sandstone.High1266.1%
Loess-Covered Drift PlainsPre-Illinoian and Illinoian glacial deposits, and loess.High1333.9%

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

Sac County beside the ground around it

On high-potential ground Sac County is close to Iowa as a whole: 100% of its land against 98.8%. Of the 7 counties that border it, none has as large a share of high-potential ground; Calhoun County comes nearest at 100%.

Share of land by USGS radon potential: Sac County, the 7 counties bordering it and Iowa
AreaEPA zoneLow potentialModerate potentialHigh potential
Sac CountyZone 1NoneNone100%
Ida CountyZone 1NoneNone100%
Calhoun CountyZone 1NoneNone100%
Carroll CountyZone 1NoneNone100%
Crawford CountyZone 1NoneNone100%
Buena Vista CountyZone 1NoneNone100%
Pocahontas CountyZone 1NoneNone100%
Cherokee CountyZone 1NoneNone100%
Iowa99 counties, pooled by land areaVariesNone1.2%98.8%

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

Local help

Sac County, Local resources

Radon testing and mitigation in Sac County

What Iowa's program says
Phone
(515) 281-4928
Licensing of radon professionals
Iowa’s radon program approves applications for persons who wish to become certified to perform radon testing or credentialed to perform mitigation and laboratories that provide radon testing devices and analytical services.
Disclosure when a home is sold or rented
However, per Iowa Code chapters 543B.9 and 543B.18 and Iowa Administrative Code 193E Chapter 14 administered by the Iowa Real Estate Commission, a seller must disclose any known tests for the presence of radon and if yes, provide the date of last report and the result(s).

What it means

Sac County, Questions

Questions about radon in Sac County

Are radon levels high in Sac County?

Over the 2008 to 2017 laboratory totals, 76.6% of the radon tests reported to CDC for Sac County, Iowa were at or above 4 pCi/L, and the median reported pre-mitigation result was 7.0 pCi/L. Of 99 Iowa counties with 30 or more tests for the same period, 9 reported a higher share; pooled, the state comes to 58.5%.

Which counties border Sac County?

Sac County borders 7 counties: Ida County, Calhoun County, Carroll County, Crawford County, Buena Vista County, Pocahontas County and Cherokee County.

Products

Sac County, Products

Testing a home in Sac County

In Sac County, 76.6% of 491 tests reported to CDC over the 2008 to 2017 laboratory totals reached 4 pCi/L, against 58.5% pooled across Iowa. In Zone 1 the year-round level in Sac 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

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

Explore

Sac County, Bordering counties

Counties bordering Sac County

Calculated by Radon411

Sac County, Cities and towns

Cities and towns in Sac County

About 9,525 people live in Sac County by the Census Bureau's estimate for July 1, 2025, 266 fewer than in 2020 (−2.7%). That works out to 17 people per square mile of land. Its largest town, Sac City, has 1,993 residents, 20.9% of the total. Testing is reported here more often than across the state: CDC's 491 reported tests for 2008 to 2017 come to 51.5 for every 1,000 residents (2025 estimate), against 29.4 for Iowa.

From Sac City to Nemaha, CDC publishes no figure by town: each reads Sac County's.

The cities and towns in Sac County by residents, July 1, 2025
PlaceResidentsSince 2020Share of residents
Sac City1,993−3.1%20.9%
Lake View1,122+0.3%11.8%
Odebolt967−2.6%10.2%
Wall Lake736−2.4%7.7%
Schaller701−3.6%7.4%
Early567−3.6%6.0%
Lyttonextends beyond Sac County270−3.9%Counted whole
Auburn252−3.4%2.6%
Nemaha65−3.0%0.7%

9 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). A place that extends beyond Sac County is counted whole, so it has no share.

Sac County, Homes

Homes in Sac County

Sac County is a place of houses on their own lots: 86% of its 5,122 homes are detached single-family houses, against 72% across Iowa. The homes are older than Iowa's as a whole: half were built before 1955 (1971 for Iowa), and 55% date from before 1960. Owners live in 78% of the occupied homes (Iowa: 72%), so for most households a test and a fix are their own to order.

Homes in Sac County, Iowa, 2019 to 2023
HomesSac CountyIowa
Housing units5,1221,427,175
Detached houses86%72%
In buildings of 5 or more4%14%
Mobile homes3%3%
Built before 196055%39%
Built since 20009%21%
Middle year built19551971
Owner-occupied78%72%

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