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Radon Levels in Webster Parish, Louisiana

EPA puts Webster Parish in Zone 3, its lowest radon zone, and most reported tests there come back low, though 0.0% of 138 (2022) 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%

    0.4 pts below LA

    Webster Parish
    0.0%
    Louisiana
    0.4%

    138 tests, 2022

  • Median result

    0.2pCi/L

    Below action level

    Webster Parish
    0.2 pCi/L
    EPA
    4.0 pCi/L

    Midpoint of the tests, 2022

  • Tests reported

    138

    7th of 9 by tests

    Webster Parish
    138
    Caddo Parish
    486

    Reported to CDC before any fix, 2022

  • 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

    2 of 9

    Top quarter

    Webster Parish
    0.0%
    Caddo Parish
    1.9%

    By share, of 9 with 30+ tests

Read a result for Webster Parish

Starts at Webster 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. Webster Parish's median reported result, 2022.

Interpret this reading

The data

Webster Parish, At a glance

Webster Parish at a glance

Predicted: EPA radon zone

EPA Zone 3: lower predicted potential

is EPA's lowest class, and its forecast for Webster 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 Webster Parish, 2022

Share of reported tests at or above 4 pCi/L, by year, Webster Parish
Share of reported tests at or above 4 pCi/L, by year, Webster Parish
YearShare of reported tests at or above 4 pCi/L
20190.0%
20220.0%

2022: 0.0%. Across these years the share ran from 0.0% to 0.0%. Each column counts radon tests reported to CDC that year, not homes.

What these figures count

These are the 138 tests reported to CDC for Webster Parish over 2022, 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: 2022. Measured data period: 2005 to 2022 (every CDC figure on file).

How to read these figures

Webster Parish, Compared

Webster Parish radon figures, compared

Calculated by Radon411

Only 0 of 138 radon tests reported for Webster Parish in 2022 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 0.7 pCi/L.

Across 12 Louisiana counties pooled together, 0.4% of tests reached that level, so Webster Parish runs 0.4 points below its state. Against the national pool of 23.9%, the gap is 23.9 points lower. Its place in the state: 2nd of 9 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, 138 tests (100.0%) came in under 2 pCi/L, against 98.1% statewide, and 0 tests (0.0%) fell between 2 and 4, against 1.5% statewide. USGS geology rates 100% of the county's land low radon potential.

The busiest year on file was 2022, with 138 tests reported; the quietest, 2019, had 6.

Webster Parish against Louisiana, the United States and nearby counties, 2022
AreaTestsAt or above 4 pCi/LMedianDifference from Webster Parish
Webster Parish1380.0%0.2 pCi/LThis county
Louisiana, pooled12 counties, pooled2,0220.4%Not pooled+0.4 points
United States, pooled853 counties, pooled333,14023.9%Not pooled+23.9 points
Caddo Parishhighest in the state4861.9%0.4 pCi/L+1.9 points
West Baton Rouge Parishlowest in the state420.0%0.6 pCi/LLevel
Where Webster Parish's reported results fell, 2022, beside Louisiana and the United States
ResultWebster Parish testsWebster Parish shareLouisiana shareU.S. shareAgainst Louisiana
Under 2 pCi/L138100.0%98.1%54.5%+1.9 points
2 to 4 pCi/L00.0%1.5%21.7%−1.5 points
4 pCi/L and above00.0%0.4%23.9%−0.4 points
Webster Parish ranked among the 9 Louisiana counties with 30 or more tests, by share at or above 4 pCi/L, 2022
CountyRankTestsAt or above 4 pCi/LMedian
Caddo Parish1 of 94861.9%0.4 pCi/L
East Baton Rouge Parish2 of 94470.0%0.2 pCi/L
Rapides Parish2 of 92040.0%0.4 pCi/L
Lafayette Parish2 of 92010.0%0.2 pCi/L
Orleans Parish2 of 91980.0%0.3 pCi/L
Union Parish2 of 91920.0%0.2 pCi/L
Webster Parish2 of 91380.0%0.2 pCi/L
Assumption Parish2 of 91020.0%0.2 pCi/L
West Baton Rouge Parish2 of 9420.0%0.6 pCi/L
Webster Parish radon tests by year, against Louisiana's pooled share
YearTestsAt or above 4 pCi/LMedianHighestLouisiana, pooledChange from the row before
20221380.0%0.2 pCi/L0.7 pCi/L0.4%Level
201960.0%0.3 pCi/L0.3 pCi/L2.0%First on file

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

Webster Parish, Geology

The ground under Webster Parish

Predicted

USGS's geologic map puts all of Webster 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 Webster 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.

Webster Parish beside the ground around it

Neither Webster Parish nor Louisiana as a whole has any land USGS rates above low potential. None of the 5 counties that border it has any moderate-potential ground either.

Share of land by USGS radon potential: Webster Parish, the 5 counties bordering it and Louisiana
AreaEPA zoneLow potentialModerate potentialHigh potential
Webster ParishZone 3100%NoneNone
Bossier ParishZone 3100%NoneNone
Claiborne ParishZone 3100%NoneNone
Bienville ParishZone 3100%NoneNone
Columbia County, ARZone 3100%NoneNone
Lafayette County, ARZone 3100%NoneNone
Louisiana64 parishes, pooled by land areaVaries98.4%NoneNone

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

Local help

Webster Parish, Local resources

Radon testing and mitigation in Webster Parish

What it means

Webster Parish, Questions

Questions about radon in Webster Parish

Are radon levels high in Webster Parish?

In 2022, 0.0% of the radon tests reported to CDC for Webster Parish, Louisiana were at or above 4 pCi/L, and the median reported pre-mitigation result was 0.2 pCi/L. Of 9 Louisiana counties with 30 or more tests for the same period, 1 reported a higher share; pooled, the state comes to 0.4%.

Which counties border Webster Parish?

Webster Parish borders 5 counties: Bossier Parish, LA, Claiborne Parish, LA, Bienville Parish, LA, Columbia County, AR and Lafayette County, AR.

Products

Webster Parish, Products

Testing a home in Webster Parish

In Webster Parish, 0.0% of 138 tests reported to CDC in 2022 reached 4 pCi/L, against 0.4% 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 Webster Parish.

Test kits and monitors3

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Best radon monitors for Webster Parish homes, compared

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Webster Parish, Bordering counties

Counties bordering Webster Parish

Calculated by Radon411

Webster Parish, Cities and towns

Cities and towns in Webster Parish

Webster Parish has been losing residents: from 36,884 in 2020 to 34,948 on July 1, 2025, a fall of 5.2% by the Census Bureau's estimates. That works out to 59 people per square mile of land. Its largest town, Minden, has 11,103 residents, 31.8% of the total. Together its 11 incorporated places hold 57.8% of those residents; the other 42.2% live outside any of them. Testing is reported here more often than across the state: CDC's 138 reported tests for 2022 come to 3.9 for every 1,000 residents (2025 estimate), against 0.4 for Louisiana.

From Minden to Shongaloo, CDC publishes no figure by town: each reads Webster Parish's.

The cities and towns in Webster Parish by residents, July 1, 2025
PlaceResidentsSince 2020Share of residents
Minden11,103−6.4%31.8%
Springhill4,437−7.2%12.7%
Sibley1,068−5.0%3.1%
Cotton Valley743−5.7%2.1%
Cullen676−6.1%1.9%
Sarepta671−5.6%1.9%
Doyline646−4.0%1.8%
Dixie Inn276−6.4%0.8%
Dubberly238−4.4%0.7%
Heflin204−3.8%0.6%
Shongaloo140−5.4%0.4%

11 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).

Webster Parish, Homes

Homes in Webster Parish

Of Webster Parish's 18,341 homes, 68% are detached houses, against 65% across Louisiana; 22% are mobile homes. The homes are older than Louisiana's as a whole: half were built before 1974 (1982 for Louisiana), and 19% date from before 1960. 68% 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 Webster Parish, Louisiana, 2019 to 2023
HomesWebster ParishLouisiana
Housing units18,3412,094,002
Detached houses68%65%
In buildings of 5 or more4%11%
Mobile homes22%13%
Built before 196019%19%
Built since 200014%27%
Middle year built19741982
Owner-occupied68%67%

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