Skip to content
RADON411

Locations and reports

Radon Levels in Greenville County, South Carolina

EPA puts Greenville County in Zone 1, its highest radon zone, and 19.6% of its 12,004 reported radon tests (2008 to 2017, laboratory totals) were 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

    19.6%

    0.2 pts above SC

    Greenville
    19.6%
    SC
    19.4%

    12,004 tests, 2008 to 2017

  • Median result

    1.7pCi/L

    Below action level

    Greenville
    1.7 pCi/L
    EPA
    4.0 pCi/L

    Midpoint of the tests, 2008 to 2017

  • Tests reported

    12,004

    Most tested in SC

    Greenville
    12,004

    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 SC

    4 of 24

    Top quarter

    Greenville
    19.6%
    Oconee
    42.6%

    By share, of 24 with 30+ tests

Read a result for Greenville County

Starts at Greenville County's median, 1.7 pCi/L

1.7pCi/L

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

EPA’s reading of 1.7 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. Greenville County's median reported result, 2008 to 2017.

Interpret this reading

The data

Greenville County, At a glance

Greenville County at a glance

Predicted: EPA radon zone

EPA Zone 1: highest predicted potential

EPA puts all of Greenville 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: Moderate across 100% of the county's area

Predicted: EPA Map of Radon Zones

Measured: tests reported to CDC

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

Reported results by concentration band, Greenville County, 2008 to 2017, laboratory
Under 2 pCi/L: 55%2 to 4 pCi/L: 25%4 pCi/L and above: 20%

Of 12,004 pre-mitigation tests reported to CDC, not homes in this area.

Reported results by concentration band, Greenville County, 2008 to 2017, laboratory: data table
Result bandTests MeasuredShare Measured
Under 2 pCi/L6,58654.9%
2 to 4 pCi/L3,06825.6%
4 pCi/L and above2,35019.6%
What these figures count

These are the 12,004 tests reported to CDC for Greenville 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

Greenville County, Compared

Greenville County radon figures, compared

Calculated by Radon411

Greenville County's 12,004 reported tests over the 2008 to 2017 laboratory totals had a middle value of 1.7 pCi/L and a maximum of 222.7 pCi/L, and 19.6% reached 4 pCi/L. South Carolina as a whole (46 South Carolina counties, pooled) comes to 19.4%: 0.2 points lower than here.

Among its state's counties it ranks 4th of 24 South Carolina counties with 30 or more tests for the same period. Statewide for the same period, Oconee County reported the highest share (42.6%) and Florence County the lowest (0.0%).

Below the action level, 6,586 tests (54.9%) came in under 2 pCi/L, against 57.4% statewide, and 3,068 tests (25.6%) fell between 2 and 4, against 23.1% statewide. CDC's ten-year totals for Greenville County went from 9,513 tests (2005 to 2014) to 12,004 (2008 to 2017), the share going from 21.4% to 19.6%.

EPA's 1993 zone map puts Greenville County in Zone 1, a predicted county average above 4 pCi/L. USGS geology rates 100% of the county's land moderate radon potential.

Next door, the shares run from 11.1% in Anderson County to 47.8% in Transylvania County, NC, with Spartanburg County, Laurens County and Anderson County below Greenville County.

CDC also counts 273 tests taken after mitigation in Greenville County for the same period: tests in homes where a fix was already in.

Greenville County against South Carolina, the United States and nearby counties, 2008 to 2017, laboratory
AreaTestsAt or above 4 pCi/LMedianDifference from Greenville County
Greenville County12,00419.6%1.7 pCi/LThis county
South Carolina, pooled46 counties, pooled26,48119.4%Not pooled−0.2 points
United States, pooled2,661 counties, pooled2,013,54435.7%Not pooled+16.1 points
Oconee Countyhighest in the state2,46942.6%3.3 pCi/L+23.0 points
Florence Countylowest in the state590.0%0.7 pCi/L−19.6 points
Transylvania County, NCborders it3,86247.8%3.7 pCi/L+28.2 points
Henderson County, NCborders it4,09341.8%3.3 pCi/L+22.2 points
Polk County, NCborders it59429.8%2.4 pCi/L+10.2 points
Pickens County, SCborders it1,71723.6%1.8 pCi/L+4.0 points
Abbeville County, SCborders it6622.7%1.8 pCi/L+3.1 points
Spartanburg County, SCborders it3,28019.1%1.7 pCi/L−0.5 points
Laurens County, SCborders it24413.9%1.3 pCi/L−5.7 points
Anderson County, SCborders it1,73311.1%1.1 pCi/L−8.5 points
Where Greenville County's reported results fell, 2008 to 2017, laboratory, beside South Carolina and the United States
ResultGreenville County testsGreenville County shareSouth Carolina shareU.S. shareAgainst South Carolina
Under 2 pCi/L6,58654.9%57.4%39.6%−2.5 points
2 to 4 pCi/L3,06825.6%23.1%24.7%+2.5 points
4 pCi/L and above2,35019.6%19.4%35.7%+0.2 points
Greenville 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
Greenville 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 201712,00419.6%1.7 pCi/L222.7 pCi/L19.4%−0.3 points
2007 to 201611,40219.9%1.8 pCi/L104.6 pCi/L19.3%−0.9 points
2006 to 201510,53920.8%1.8 pCi/L104.6 pCi/L19.8%−0.6 points
2005 to 20149,51321.4%1.8 pCi/L104.6 pCi/L19.8%First on file

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

Greenville County, Geology

The ground under Greenville County

Predicted

USGS's geologic map puts all of Greenville County's mapped land in one class: moderate radon potential. All of it lies in the area the map calls Inner Piedmont Belt, to which USGS gives a radon index of 11, in the moderate band (9 to 11).

USGS's geologic areas under Greenville County
AreaThe rock, in USGS's wordsPotentialRadon indexShare of land
Inner Piedmont BeltProterozoic through Cambrian biotite gneiss and schist, and mica schist.Moderate11100%

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

Greenville County beside the ground around it

Across South Carolina 0.2% of the land is rated high; none of Greenville County's is. Of the 8 counties that border it, 2 have more high-potential ground, Henderson County, NC the most at 52.6%.

Share of land by USGS radon potential: Greenville County, the 8 counties bordering it and South Carolina
AreaEPA zoneLow potentialModerate potentialHigh potential
Greenville CountyZone 1None100%None
Pickens CountyZone 2None100%None
Spartanburg CountyZone 2None100%None
Anderson CountyZone 2None100%None
Laurens CountyZone 242.4%57.6%None
Polk County, NCZone 2None100%None
Transylvania County, NCZone 1None48.0%52.0%
Henderson County, NCZone 1None47.4%52.6%
Abbeville CountyZone 249.6%50.4%None
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

Greenville County, Local resources

Radon testing and mitigation in Greenville County

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

What it means

Greenville County, Questions

Questions about radon in Greenville County

Are radon levels high in Greenville County?

Over the 2008 to 2017 laboratory totals, 19.6% of the radon tests reported to CDC for Greenville County, South Carolina were at or above 4 pCi/L, and the median reported pre-mitigation result was 1.7 pCi/L. Of 24 South Carolina counties with 30 or more tests for the same period, 3 reported a higher share; pooled, the state comes to 19.4%.

Which counties border Greenville County?

Greenville County borders 8 counties: Pickens County, SC, Spartanburg County, SC, Anderson County, SC, Laurens County, SC, Polk County, NC, Transylvania County, NC, Henderson County, NC and Abbeville County, SC.

Products

Greenville County, Products

Testing a home in Greenville County

In Greenville County, 19.6% of 12,004 tests reported to CDC over the 2008 to 2017 laboratory totals reached 4 pCi/L, against 19.4% pooled across South Carolina. In Zone 1 the year-round level in Greenville 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

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

Explore

Greenville County, Bordering counties

Counties bordering Greenville County

Calculated by Radon411

Greenville County, Cities and towns

Cities and towns in Greenville County

Greenville County is growing: the Census Bureau puts it at 583,125 residents on July 1, 2025, up 10.6% from 527,244 in 2020. That works out to 742 people per square mile of land. No town dominates: Greenville, the largest, has 75,310 residents, 12.9% of the total. Testing is reported here more often than across the state: CDC's 12,004 reported tests for 2008 to 2017 come to 20.6 for every 1,000 residents (2025 estimate), against 4.8 for South Carolina.

From Greenville to Travelers Rest, CDC publishes no figure by town: each reads Greenville County's.

The cities and towns in Greenville County by residents, July 1, 2025
PlaceResidentsSince 2020Share of residents
Greenville75,310+5.4%12.9%
Greerextends beyond Greenville County50,007+39.2%Counted whole
Mauldin31,465+26.8%5.4%
Simpsonville28,459+20.4%4.9%
Fountain Innextends beyond Greenville County14,722+40.1%Counted whole
Travelers Rest9,135+16.8%1.6%

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 Greenville County is counted whole, so it has no share.

Greenville County, Homes

Homes in Greenville County

Of Greenville County's 233,254 homes, 68% are detached houses, against 64% across South Carolina; 16% are in buildings of five or more homes. Half of its homes were built before 1992, close to South Carolina's 1991: 13% date from before 1960 and 36% from 2000 or later. 69% of occupied homes are lived in by their owner (South Carolina: 71%); in the rest a tenant can run a test, but a fix is the landlord's to make.

Homes in Greenville County, South Carolina, 2019 to 2023
HomesGreenville CountySouth Carolina
Housing units233,2542,401,638
Detached houses68%64%
In buildings of 5 or more16%13%
Mobile homes8%15%
Built before 196013%13%
Built since 200036%35%
Middle year built19921991
Owner-occupied69%71%

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