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Radon Levels in Winn Parish, Louisiana

EPA puts Winn Parish in Zone 3, its lowest radon zone, and most reported tests there come back low, though 0.0% of 156 (2020) reached 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

    0.0%

    0.8 pts below LA

    Winn Parish
    0.0%
    Louisiana
    0.8%

    156 tests, 2020

  • Median result

    0.2pCi/L

    Below action level

    Winn Parish
    0.2 pCi/L
    EPA
    4.0 pCi/L

    Midpoint of the tests, 2020

  • Tests reported

    156

    5th of 13 by tests

    Winn Parish
    156
    Jefferson Parish
    339

    Reported to CDC before any fix, 2020

  • EPA radon zone

    Zone 3

    Lower potential

    1. 1
    2. 2
    3. Zone 3

    1 highest, 3 lowest

    EPA predicts under 2 pCi/L indoors

  • Rank in Louisiana

    3 of 13

    Top quarter

    Winn Parish
    0.0%
    Lafayette Parish
    19.0%

    By share, of 13 with 30+ tests

Read a result for Winn Parish

Starts at Winn Parish's median, 0.2 pCi/L

0.2pCi/L

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

EPA’s reading of 0.2 pCi/L

Below 2 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 below 2 pCi/L, the level at which EPA says a fix should be considered. Winn Parish's median reported result, 2020.

Interpret this reading

The data

Winn Parish, At a glance

Winn Parish at a glance

Predicted: EPA radon zone

EPA Zone 3: lower predicted potential

is EPA's lowest class, and its forecast for Winn Parish as a whole is an average indoor of less than 2 pCi/L (less than 75 Bq/m³). A low zone clears no address in it: homes above EPA's turn up in all three zones.

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

Predicted: EPA Map of Radon Zones

Measured: tests reported to CDC

Radon tests reported for Winn Parish, 2020

Reported results by concentration band, Winn Parish, 2020
Under 2 pCi/L: 94%2 to 4 pCi/L: 6%4 pCi/L and above: 0%

Of 156 pre-mitigation tests reported to CDC, not homes in this area.

Reported results by concentration band, Winn Parish, 2020: data table
Result bandTests MeasuredShare Measured
Under 2 pCi/L14794.2%
2 to 4 pCi/L95.8%
4 pCi/L and above00.0%
What these figures count

These are the 156 tests reported to CDC for Winn Parish over 2020, many from homes being sold or already suspected of a problem: they describe the parish's reported tests, not this house.

Measured: CDC tracking data. Figure above: 2020. Measured data period: 2005 to 2020 (every CDC figure on file).

How to read these figures

Winn Parish, Compared

Winn Parish radon figures, compared

Calculated by Radon411

Only 0 of 156 radon tests reported for Winn Parish in 2020 reached 4 pCi/L (0.0%). The median result, 0.2 pCi/L, sits below 2, well under EPA's 4 pCi/L action level, and the top reported result was 3.8 pCi/L.

Across 18 Louisiana counties pooled together, 0.8% of tests reached that level, so Winn Parish runs 0.8 points below its state. Against the national pool of 25.5%, the gap is 25.5 points lower. Its place in the state: 3rd of 13 Louisiana counties with 30 or more tests for the same period.

Zone 3 on EPA's map (predicted average under 2 pCi/L) and a 0.0% share point the same way here.

Below the action level, 147 tests (94.2%) came in under 2 pCi/L, against 94.9% statewide, and 9 tests (5.8%) fell between 2 and 4, against 4.2% statewide. USGS geology rates 100% of the county's land low radon potential.

CDC's ten-year totals for Winn Parish went from 1 tests (2005 to 2014) to 1 (2008 to 2017), the share going from 0.0% to 0.0%.

Winn Parish against Louisiana, the United States and nearby counties, 2020
AreaTestsAt or above 4 pCi/LMedianDifference from Winn Parish
Winn Parish1560.0%0.2 pCi/LThis county
Louisiana, pooled18 counties, pooled1,7760.8%Not pooled+0.8 points
United States, pooled915 counties, pooled405,35525.5%Not pooled+25.5 points
Lafayette Parishhighest in the state6319.0%2.2 pCi/L+19.0 points
Ouachita Parishlowest in the state300.0%0.8 pCi/LLevel
Where Winn Parish's reported results fell, 2020, beside Louisiana and the United States
ResultWinn Parish testsWinn Parish shareLouisiana shareU.S. shareAgainst Louisiana
Under 2 pCi/L14794.2%94.9%51.6%−0.7 points
2 to 4 pCi/L95.8%4.2%22.9%+1.6 points
4 pCi/L and above00.0%0.8%25.5%−0.8 points
Winn Parish ranked among the 13 Louisiana counties with 30 or more tests, by share at or above 4 pCi/L, 2020
CountyRankTestsAt or above 4 pCi/LMedian
Lafayette Parish1 of 136319.0%2.2 pCi/L
Caddo Parish2 of 132251.3%0.9 pCi/L
Jefferson Parish3 of 133390.0%0.2 pCi/L
Calcasieu Parish3 of 133330.0%0.2 pCi/L
East Baton Rouge Parish3 of 131920.0%0.6 pCi/L
Winn Parish3 of 131560.0%0.2 pCi/L
Livingston Parish3 of 13960.0%0.7 pCi/L
West Baton Rouge Parish3 of 13750.0%0.8 pCi/L
Vernon Parish3 of 13720.0%0.5 pCi/L
St. Tammany Parish3 of 13630.0%0.5 pCi/L
Terrebonne Parish3 of 13600.0%0.3 pCi/L
Winn Parish ten-year laboratory totals, against Louisiana's pooled share
PeriodTestsAt or above 4 pCi/LMedianHighestLouisiana, pooledChange from the row before
2008 to 201710.0%1.1 pCi/L1.1 pCi/L2.2%Level
2007 to 201610.0%1.1 pCi/L1.1 pCi/L2.6%Level
2006 to 201510.0%1.1 pCi/L1.1 pCi/L2.8%Level
2005 to 201410.0%1.1 pCi/L1.1 pCi/L2.6%First on file

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

Winn Parish, Geology

The ground under Winn Parish

Predicted

USGS's geologic map puts all of Winn Parish's mapped land in one class: low radon potential. All of it lies in the area the map calls Old Uplands, to which USGS gives a radon index of 7, in the low band (5 to 8).

USGS's geologic areas under Winn Parish
AreaThe rock, in USGS's wordsPotentialRadon indexShare of land
Old UplandsClays, silts, sands, and ironstone.Low7100%

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

Winn Parish beside the ground around it

Neither Winn Parish nor Louisiana as a whole has any land USGS rates above low potential. None of the 6 parishes that border it has any moderate-potential ground either.

Share of land by USGS radon potential: Winn Parish, the 6 parishes bordering it and Louisiana
AreaEPA zoneLow potentialModerate potentialHigh potential
Winn ParishZone 3100%NoneNone
Grant ParishZone 3100%NoneNone
Jackson ParishZone 3100%NoneNone
Caldwell ParishZone 3100%NoneNone
LaSalle ParishZone 3100%NoneNone
Natchitoches ParishZone 3100%NoneNone
Bienville ParishZone 3100%NoneNone
Louisiana64 parishes, pooled by land areaVaries98.4%NoneNone

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

Local help

Winn Parish, Local resources

Radon testing and mitigation in Winn Parish

What it means

Winn Parish, Questions

Questions about radon in Winn Parish

Are radon levels high in Winn Parish?

In 2020, 0.0% of the radon tests reported to CDC for Winn Parish, Louisiana were at or above 4 pCi/L, and the median reported pre-mitigation result was 0.2 pCi/L. Of 13 Louisiana counties with 30 or more tests for the same period, 2 reported a higher share; pooled, the state comes to 0.8%.

Which counties border Winn Parish?

Winn Parish borders 6 parishes: Grant Parish, Jackson Parish, Caldwell Parish, LaSalle Parish, Natchitoches Parish and Bienville Parish.

Products

Winn Parish, Products

Testing a home in Winn Parish

In Winn Parish, 0.0% of 156 tests reported to CDC in 2020 reached 4 pCi/L, against 0.8% pooled across Louisiana. Zone 3 is the lowest label, yet homes at or above 4 pCi/L occur in every zone: a short-term kit (2 to 90 days) is the quick first check in Winn Parish.

Test kits and monitors3

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Best radon monitors for Winn Parish homes, compared

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Winn Parish, Bordering parishes

Parishes bordering Winn Parish

Calculated by Radon411

Winn Parish, Cities and towns

Cities and towns in Winn Parish

Winn Parish is growing: the Census Bureau puts it at 14,961 residents on July 1, 2025, up 9.0% from 13,720 in 2020. That works out to 16 people per square mile of land. Its largest town, Winnfield, has 4,480 residents, 29.9% of the total. Testing is reported here more often than across the state: CDC's 156 reported tests for 2020 come to 10.4 for every 1,000 residents (2025 estimate), against 0.4 for Louisiana.

From Winnfield to Sikes, CDC publishes no figure by town: each reads Winn Parish's.

The cities and towns in Winn Parish by residents, July 1, 2025
PlaceResidentsSince 2020Share of residents
Winnfield4,480+8.4%29.9%
Dodson337+13.9%2.3%
Tullosextends beyond Winn Parish310+0.3%Counted whole
Calvin267+9.9%1.8%
Atlanta171+9.6%1.1%
Sikes125+11.6%0.8%

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). A place that extends beyond Winn Parish is counted whole, so it has no share.

Winn Parish, Homes

Homes in Winn Parish

Of Winn Parish's 6,372 homes, 66% are detached houses, against 65% across Louisiana; 25% are mobile homes. Half of its homes were built before 1978, close to Louisiana's 1982: 20% date from before 1960 and 13% from 2000 or later. 71% of occupied homes are lived in by their owner (Louisiana: 67%); in the rest a tenant can run a test, but a fix is the landlord's to make.

Homes in Winn Parish, Louisiana, 2019 to 2023
HomesWinn ParishLouisiana
Housing units6,3722,094,002
Detached houses66%65%
In buildings of 5 or more2%11%
Mobile homes25%13%
Built before 196020%19%
Built since 200013%27%
Middle year built19781982
Owner-occupied71%67%

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