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Radon Levels in Lee County, Iowa

EPA puts Lee County in Zone 1, its highest radon zone, and high results are common there: 43.6% of the 351 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

How to test this homeFind a certified tester

  • Share at 4+ pCi/L

    43.6%

    14.9 pts below IA

    Lee
    43.6%
    Iowa
    58.5%

    351 tests, 2008 to 2017

  • Median result

    3.2pCi/L

    Below action level

    Lee
    3.2 pCi/L
    EPA
    4.0 pCi/L

    Midpoint of the tests, 2008 to 2017

  • Tests reported

    351

    65th of 99 by tests

    Lee
    351
    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

    88 of 99

    Lowest quarter

    Lee
    43.6%
    Sioux
    84.2%

    By share, of 99 with 30+ tests

Read a result for Lee County

Starts at Lee County's median, 3.2 pCi/L

3.2pCi/L

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

EPA’s reading of 3.2 pCi/L

Between 2 and 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 between 2 and 4 pCi/L. EPA recommends considering a fix when the level is between 2 and 4 pCi/L. Lee County's median reported result, 2008 to 2017.

Interpret this readingWhat a fix costs

The data

Lee County, At a glance

Lee County at a glance

Predicted: EPA radon zone

EPA Zone 1: highest predicted potential

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

Reported results by concentration band, Lee County, 2008 to 2017, laboratory
Under 2 pCi/L: 30%2 to 4 pCi/L: 26%4 pCi/L and above: 44%

Of 351 pre-mitigation tests reported to CDC, not homes in this area.

Reported results by concentration band, Lee County, 2008 to 2017, laboratory: data table
Result bandTests MeasuredShare Measured
Under 2 pCi/L10630.2%
2 to 4 pCi/L9226.2%
4 pCi/L and above15343.6%
What these figures count

These are the 351 tests reported to CDC for Lee 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

Lee County, Compared

Lee County radon figures, compared

Calculated by Radon411

In Lee County, about 4 in 10 reported tests over the 2008 to 2017 laboratory totals (153 of 351) were at or above EPA's action level. Against the national pool of 35.7%, the gap is 7.9 points higher. Across 99 Iowa counties pooled together, 58.5% of tests reached that level, so Lee County runs 14.9 points below its state.

Of 5 neighbours with a figure, 3 reported a larger share at or above 4 pCi/L and 2 a smaller one; the spread is 32.1% (Van Buren County) to 68.4% (Henderson County, IL). By share, Lee County is 88th of 99 Iowa counties with 30 or more tests for the same period.

Half the tests came in under 3.2 pCi/L and half over it; the single highest reached 51.7 pCi/L. Below the action level, 106 tests (30.2%) came in under 2 pCi/L, against 21.8% statewide, and 92 tests (26.2%) fell between 2 and 4, against 19.7% statewide.

Zone 1 on EPA's map (predicted average above 4 pCi/L) and a 43.6% share point the same way here. USGS geology rates 100% of the county's land high radon potential.

CDC's ten-year totals for Lee County went from 322 tests (2005 to 2014) to 351 (2008 to 2017), the share going from 43.8% to 43.6%.

Lee County against Iowa, the United States and nearby counties, 2008 to 2017, laboratory
AreaTestsAt or above 4 pCi/LMedianDifference from Lee County
Lee County35143.6%3.2 pCi/LThis county
Iowa, pooled99 counties, pooled95,24558.5%Not pooled+14.9 points
United States, pooled2,661 counties, pooled2,013,54435.7%Not pooled−7.9 points
Sioux Countyhighest in the state1,98284.2%10.7 pCi/L+40.6 points
Decatur Countylowest in the state8525.9%2.5 pCi/L−17.7 points
Henderson County, ILborders it3868.4%5.7 pCi/L+24.8 points
Des Moines County, IAborders it43651.1%4.2 pCi/L+7.5 points
Henry County, IAborders it16846.4%3.4 pCi/L+2.8 points
Hancock County, ILborders it17743.5%3.5 pCi/L−0.1 points
Van Buren County, IAborders it5632.1%2.3 pCi/L−11.5 points
Clark County, MOborders it1729.4%2.2 pCi/L−14.2 points
Where Lee County's reported results fell, 2008 to 2017, laboratory, beside Iowa and the United States
ResultLee County testsLee County shareIowa shareU.S. shareAgainst Iowa
Under 2 pCi/L10630.2%21.8%39.6%+8.4 points
2 to 4 pCi/L9226.2%19.7%24.7%+6.5 points
4 pCi/L and above15343.6%58.5%35.7%−14.9 points
Lee 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
Muscatine County83 of 9995446.5%3.7 pCi/L
Henry County84 of 9916846.4%3.4 pCi/L
Clarke County85 of 9912045.8%3.5 pCi/L
Appanoose County86 of 9911745.3%3.7 pCi/L
Scott County87 of 993,52044.3%3.3 pCi/L
Lee County88 of 9935143.6%3.2 pCi/L
Davis County89 of 998542.4%3.1 pCi/L
Johnson County90 of 997,32141.6%3.2 pCi/L
Linn County91 of 999,39539.7%3.0 pCi/L
Lucas County92 of 998439.3%3.3 pCi/L
Wapello County93 of 9928735.9%2.7 pCi/L
Lee County ten-year laboratory totals, against Iowa's pooled share
PeriodTestsAt or above 4 pCi/LMedianHighestIowa, pooledChange from the row before
2008 to 201735143.6%3.2 pCi/L51.7 pCi/L58.5%−1.2 points
2007 to 201636244.8%3.4 pCi/L51.7 pCi/L58.6%−0.7 points
2006 to 201535845.5%3.4 pCi/L51.7 pCi/L59.4%+1.7 points
2005 to 201432243.8%3.3 pCi/L51.7 pCi/L59.6%First on file

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

Lee County, Geology

The ground under Lee County

Predicted

Most of the ground under Lee County is one class on USGS's geologic map: 99.9% of its land is high radon potential, with 0.1% moderate. 99.4% of it lies in the area the map calls Loess-Covered Drift Plains, to which USGS gives a radon index of 13, in the high band (12 to 17).

USGS's geologic areas under Lee County
AreaThe rock, in USGS's wordsPotentialRadon indexShare of land
Loess-Covered Drift PlainsPre-Illinoian and Illinoian glacial deposits, and loess.High1399.4%
Galesburg PlainIllinoian glacial deposits and loess over Paleozoic sedimentary rocks.High130.5%

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

Lee County beside the ground around it

On high-potential ground Lee County is close to Iowa as a whole: 99.9% of its land against 98.8%. Of the 6 counties that border it, 4 have more high-potential ground, Des Moines County the most at 100%.

Share of land by USGS radon potential: Lee County, the 6 counties bordering it and Iowa
AreaEPA zoneLow potentialModerate potentialHigh potential
Lee CountyZone 1None0.1%99.9%
Clark County, MOZone 2None93.4%6.6%
Van Buren CountyZone 1None8.8%91.2%
Hancock County, ILZone 1NoneNone100%
Des Moines CountyZone 1NoneNone100%
Henry CountyZone 1NoneNone100%
Henderson County, ILZone 1NoneNone100%
Iowa99 counties, pooled by land areaVariesNone1.2%98.8%

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

Local help

Lee County, Local resources

Radon testing and mitigation in Lee County

Listed radon businesses with an address in Lee County:

Listed radon professionals by town: Keokuk

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

Lee County, Questions

Questions about radon in Lee County

Are radon levels high in Lee County?

Over the 2008 to 2017 laboratory totals, 43.6% of the radon tests reported to CDC for Lee County, Iowa were at or above 4 pCi/L, and the median reported pre-mitigation result was 3.2 pCi/L. Of 99 Iowa counties with 30 or more tests for the same period, 87 reported a higher share; pooled, the state comes to 58.5%.

Which counties border Lee County?

Lee County borders 6 counties: Clark County, MO, Van Buren County, IA, Hancock County, IL, Des Moines County, IA, Henry County, IA and Henderson County, IL.

Products

Lee County, Products

Testing a home in Lee County

In Lee County, 43.6% of 351 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 Lee 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

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

Explore

Lee County, Bordering counties

Counties bordering Lee County

Calculated by Radon411

Lee County, Cities and towns

Cities and towns in Lee County

About 32,306 people live in Lee County by the Census Bureau's estimate for July 1, 2025, 1,221 fewer than in 2020 (−3.6%). That works out to 62 people per square mile of land. Its largest town, Fort Madison, has 9,935 residents, 30.8% of the total. Together its 8 incorporated places hold 68.9% of those residents; the other 31.1% live outside any of them. Reported testing is thin here: 351 tests over 2008 to 2017, or 10.9 for every 1,000 residents (2025 estimate), where Iowa as a whole comes to 29.4.

From Fort Madison to St. Paul, CDC publishes no figure by town: each reads Lee County's.

The cities and towns in Lee County by residents, July 1, 2025
PlaceResidentsSince 2020Share of residents
Fort Madison9,935−3.6%30.8%
Keokuk9,510−3.8%29.4%
West Point901−2.8%2.8%
Donnellson808−9.2%2.5%
Montrose745+0.4%2.3%
Franklin133+1.5%0.4%
Houghton126−3.1%0.4%
St. Paul104−3.7%0.3%

8 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).

Lee County, Homes

Homes in Lee County

Lee County is a place of houses on their own lots: 79% of its 15,808 homes are detached single-family houses, against 72% across Iowa. The homes are older than Iowa's as a whole: half were built before 1959 (1971 for Iowa), and 52% date from before 1960. Owners live in 75% of the occupied homes (Iowa: 72%), so for most households a test and a fix are their own to order.

Homes in Lee County, Iowa, 2019 to 2023
HomesLee CountyIowa
Housing units15,8081,427,175
Detached houses79%72%
In buildings of 5 or more8%14%
Mobile homes4%3%
Built before 196052%39%
Built since 20009%21%
Middle year built19591971
Owner-occupied75%72%

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