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Radon Levels in Oconee County, South Carolina

EPA puts Oconee County in Zone 2, its middle radon zone, and high results are common there: 42.6% of the 2,469 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

    42.6%

    23.2 pts above SC

    Oconee
    42.6%
    SC
    19.4%

    2,469 tests, 2008 to 2017

  • Median result

    3.3pCi/L

    Below action level

    Oconee
    3.3 pCi/L
    EPA
    4.0 pCi/L

    Midpoint of the tests, 2008 to 2017

  • Tests reported

    2,469

    3rd of 24 by tests

    Oconee
    2,469
    Greenville
    12,004

    Reported to CDC before any fix, 2008 to 2017

  • EPA radon zone

    Zone 2

    Moderate potential

    1. 1
    2. Zone 2
    3. 3

    1 highest, 3 lowest

    EPA predicts 2 to 4 pCi/L indoors

  • Rank in SC

    1 of 24

    Top quarter

    Oconee
    42.6%
    Oconee
    42.6%

    By share, of 24 with 30+ tests

Read a result for Oconee County

Starts at Oconee County's median, 3.3 pCi/L

3.3pCi/L

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

EPA’s reading of 3.3 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. Oconee County's median reported result, 2008 to 2017.

Interpret this readingWhat a fix costs

The data

Oconee County, At a glance

Oconee County at a glance

Predicted: EPA radon zone

EPA Zone 2: moderate predicted potential

Oconee County is a county: EPA's forecast for it as a whole is an average indoor of 2 to 4 pCi/L (75 to 150 Bq/m³). It describes no single address, and homes above EPA's are found in every zone, this one included.

USGS geologic potential: Moderate across 89% of the county's area

Predicted: EPA Map of Radon Zones

Measured: tests reported to CDC

Radon tests reported for Oconee County, 2008 to 2017, laboratory

Reported results by concentration band, Oconee County, 2008 to 2017, laboratory
Under 2 pCi/L: 30%2 to 4 pCi/L: 27%4 pCi/L and above: 43%

Of 2,469 pre-mitigation tests reported to CDC, not homes in this area.

Reported results by concentration band, Oconee County, 2008 to 2017, laboratory: data table
Result bandTests MeasuredShare Measured
Under 2 pCi/L74430.1%
2 to 4 pCi/L67227.2%
4 pCi/L and above1,05342.6%
What these figures count

These are the 2,469 tests reported to CDC for Oconee 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

Oconee County, Compared

Oconee County radon figures, compared

Calculated by Radon411

In Oconee County, about 4 in 10 reported tests over the 2008 to 2017 laboratory totals (1,053 of 2,469) were at or above EPA's action level. Against the national pool of 35.7%, the gap is 6.9 points higher. Across 46 South Carolina counties pooled together, 19.4% of tests reached that level, so Oconee County runs 23.2 points above its state.

Of 9 neighbours with a figure, 1 reported a larger share at or above 4 pCi/L and 8 a smaller one; the spread is 11.1% (Anderson County) to 47.8% (Transylvania County, NC). By share, Oconee County is 1st of 24 South Carolina counties with 30 or more tests for the same period.

Half the tests came in under 3.3 pCi/L and half over it; the single highest reached 69.7 pCi/L. Below the action level, 744 tests (30.1%) came in under 2 pCi/L, against 57.4% statewide, and 672 tests (27.2%) fell between 2 and 4, against 23.1% statewide.

Zone 2 on EPA's map (predicted average between 2 and 4 pCi/L) and a 42.6% share point the same way here. USGS geology rates 89% of the county's land moderate radon potential. CDC also counts 90 tests taken after mitigation in Oconee County for the same period: tests in homes where a fix was already in.

CDC's ten-year totals for Oconee County went from 2,020 tests (2005 to 2014) to 2,469 (2008 to 2017), the share going from 44.8% to 42.6%.

Oconee County against South Carolina, the United States and nearby counties, 2008 to 2017, laboratory
AreaTestsAt or above 4 pCi/LMedianDifference from Oconee County
Oconee County2,46942.6%3.3 pCi/LThis county
South Carolina, pooled46 counties, pooled26,48119.4%Not pooled−23.2 points
United States, pooled2,661 counties, pooled2,013,54435.7%Not pooled−6.9 points
Abbeville Countyhighest in the state6622.7%1.8 pCi/L−19.9 points
Florence Countylowest in the state590.0%0.7 pCi/L−42.6 points
Transylvania County, NCborders it3,86247.8%3.7 pCi/L+5.2 points
Hart County, GAborders it10740.2%3.4 pCi/L−2.4 points
Habersham County, GAborders it12837.5%3.1 pCi/L−5.1 points
Franklin County, GAborders it2737.0%2.7 pCi/L−5.6 points
Jackson County, NCborders it1,02627.7%2.2 pCi/L−14.9 points
Rabun County, GAborders it6926.1%2.0 pCi/L−16.5 points
Stephens County, GAborders it7925.3%2.2 pCi/L−17.3 points
Pickens County, SCborders it1,71723.6%1.8 pCi/L−19.0 points
Macon County, NCborders it1,35417.1%1.4 pCi/L−25.5 points
Anderson County, SCborders it1,73311.1%1.1 pCi/L−31.5 points
Where Oconee County's reported results fell, 2008 to 2017, laboratory, beside South Carolina and the United States
ResultOconee County testsOconee County shareSouth Carolina shareU.S. shareAgainst South Carolina
Under 2 pCi/L74430.1%57.4%39.6%−27.3 points
2 to 4 pCi/L67227.2%23.1%24.7%+4.1 points
4 pCi/L and above1,05342.6%19.4%35.7%+23.2 points
Oconee County ranked among the 24 South Carolina counties with 30 or more tests, by share at or above 4 pCi/L, 2008 to 2017, laboratory
CountyRankTestsAt or above 4 pCi/LMedian
Oconee County1 of 242,46942.6%3.3 pCi/L
Pickens County2 of 241,71723.6%1.8 pCi/L
Abbeville County3 of 246622.7%1.8 pCi/L
Greenville County4 of 2412,00419.6%1.7 pCi/L
Spartanburg County5 of 243,28019.1%1.7 pCi/L
Newberry County6 of 247516.0%1.1 pCi/L
Laurens County7 of 2424413.9%1.3 pCi/L
Cherokee County8 of 2415313.7%1.6 pCi/L
Lancaster County9 of 2437413.6%1.6 pCi/L
York County10 of 241,41213.6%1.2 pCi/L
Aiken County11 of 2424113.3%1.3 pCi/L
Oconee County ten-year laboratory totals, against South Carolina's pooled share
PeriodTestsAt or above 4 pCi/LMedianHighestSouth Carolina, pooledChange from the row before
2008 to 20172,46942.6%3.3 pCi/L69.7 pCi/L19.4%−0.5 points
2007 to 20162,34043.1%3.3 pCi/L69.7 pCi/L19.3%−1.6 points
2006 to 20152,17644.7%3.4 pCi/L69.7 pCi/L19.8%−0.1 points
2005 to 20142,02044.8%3.5 pCi/L69.7 pCi/L19.8%First on file

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

Oconee County, Geology

The ground under Oconee County

Predicted

Most of the ground under Oconee County is one class on USGS's geologic map: 89.0% of its land is moderate radon potential, with 11.0% high. The map puts 80.4% of Oconee County in the area it calls Inner Piedmont Belt and 11.0% in Brevard Fault Zone, with 2 smaller areas beside them. USGS gives the first a radon index of 11, in the moderate band (9 to 11), and the second 12, in the high band (12 to 17).

USGS's geologic areas under Oconee County
AreaThe rock, in USGS's wordsPotentialRadon indexShare of land
Inner Piedmont BeltProterozoic through Cambrian biotite gneiss and schist, and mica schist.Moderate1180.4%
Brevard Fault ZoneSchist, marble and phyllonite.High1211.0%
Blue RidgeUranium-bearing granites, biotite and granitic gneiss.Moderate108.1%
Georgiabama Thrust Stack (South)Schist, amphibolite and granite.Moderate90.6%

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

Oconee County beside the ground around it

Oconee County has more high-potential ground than South Carolina as a whole: 11.0% of its land against 0.2%. Of the 10 counties that border it, 1 has more high-potential ground, Transylvania County, NC the most at 52.0%.

Share of land by USGS radon potential: Oconee County, the 10 counties bordering it and South Carolina
AreaEPA zoneLow potentialModerate potentialHigh potential
Oconee CountyZone 2None89.0%11.0%
Stephens County, GAZone 2None100%None
Rabun County, GAZone 2None100%None
Pickens CountyZone 2None100%None
Habersham County, GAZone 2None100%None
Franklin County, GAZone 2None100%None
Hart County, GAZone 2None100%None
Anderson CountyZone 2None100%None
Jackson County, NCZone 2None100%None
Macon County, NCZone 2None100%None
Transylvania County, NCZone 1None48.0%52.0%
South Carolina46 counties, pooled by land areaVaries80.8%18.2%0.2%

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

Local help

Oconee County, Local resources

Radon testing and mitigation in Oconee County

What South Carolina's program says
Phone
1-800-768-0362
Email
radon@des.sc.gov

What it means

Oconee County, Questions

Questions about radon in Oconee County

Are radon levels high in Oconee County?

Over the 2008 to 2017 laboratory totals, 42.6% of the radon tests reported to CDC for Oconee County, South Carolina were at or above 4 pCi/L, and the median reported pre-mitigation result was 3.3 pCi/L. Of 24 South Carolina counties with 30 or more tests for the same period, none reported a higher share; pooled, the state comes to 19.4%.

Which counties border Oconee County?

Oconee County borders 10 counties: Stephens County, GA, Rabun County, GA, Pickens County, SC, Habersham County, GA, Franklin County, GA, Hart County, GA, Anderson County, SC, Jackson County, NC, Macon County, NC and Transylvania County, NC.

Products

Oconee County, Products

Testing a home in Oconee County

In Oconee County, 42.6% of 2,469 tests reported to CDC over the 2008 to 2017 laboratory totals reached 4 pCi/L, against 19.4% pooled across South Carolina. In Zone 2 a short-term kit (2 to 90 days) is the quick first check in Oconee County; a long-term test tells the year-round average.

Test kits and monitors3

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Best radon monitors for Oconee County homes, compared

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Oconee County, Bordering counties

Counties bordering Oconee County

Calculated by Radon411

Oconee County, Cities and towns

Cities and towns in Oconee County

Oconee County is growing: the Census Bureau puts it at 83,775 residents on July 1, 2025, up 6.3% from 78,794 in 2020. That works out to 134 people per square mile of land. No town dominates: Seneca, the largest, has 9,424 residents, 11.2% of the total. Together its 5 incorporated places hold 20.0% of those residents; the other 80.0% live outside any of them. Testing is reported here more often than across the state: CDC's 2,469 reported tests for 2008 to 2017 come to 29.5 for every 1,000 residents (2025 estimate), against 4.8 for South Carolina.

From Seneca to Salem, CDC publishes no figure by town: each reads Oconee County's.

The cities and towns in Oconee County by residents, July 1, 2025
PlaceResidentsSince 2020Share of residents
Seneca9,424+6.5%11.2%
Walhalla4,320+5.8%5.2%
Westminster2,504+5.4%3.0%
West Union395+6.5%0.5%
Salem129+8.4%0.2%

5 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).

Oconee County, Homes

Homes in Oconee County

Of Oconee County's 41,514 homes, 68% are detached houses, against 64% across South Carolina; 21% are mobile homes. Half of its homes were built before 1990, close to South Carolina's 1991: 12% date from before 1960 and 31% from 2000 or later. Owners live in 75% of the occupied homes (South Carolina: 71%), so for most households a test and a fix are their own to order.

Homes in Oconee County, South Carolina, 2019 to 2023
HomesOconee CountySouth Carolina
Housing units41,5142,401,638
Detached houses68%64%
In buildings of 5 or more5%13%
Mobile homes21%15%
Built before 196012%13%
Built since 200031%35%
Middle year built19901991
Owner-occupied75%71%

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