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Radon Levels in Lancaster County, South Carolina

EPA puts Lancaster County in Zone 3, its lowest radon zone, and most reported tests there come back low, though 13.6% of 374 (2008 to 2017, laboratory totals) 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

    13.6%

    5.8 pts below SC

    Lancaster
    13.6%
    SC
    19.4%

    374 tests, 2008 to 2017

  • Median result

    1.6pCi/L

    Below action level

    Lancaster
    1.6 pCi/L
    EPA
    4.0 pCi/L

    Midpoint of the tests, 2008 to 2017

  • Tests reported

    374

    9th of 24 by tests

    Lancaster
    374
    Greenville
    12,004

    Reported to CDC before any fix, 2008 to 2017

  • 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 SC

    9 of 24

    Middle half

    Lancaster
    13.6%
    Oconee
    42.6%

    By share, of 24 with 30+ tests

Read a result for Lancaster County

Starts at Lancaster County's median, 1.6 pCi/L

1.6pCi/L

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

EPA’s reading of 1.6 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. Lancaster County's median reported result, 2008 to 2017.

Interpret this reading

The data

Lancaster County, At a glance

Lancaster County at a glance

Predicted: EPA radon zone

EPA Zone 3: lower predicted potential

is EPA's lowest class, and its forecast for Lancaster County 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 84% of the county's area

Predicted: EPA Map of Radon Zones

Measured: tests reported to CDC

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

Reported results by concentration band, Lancaster County, 2008 to 2017, laboratory
Under 2 pCi/L: 56%2 to 4 pCi/L: 30%4 pCi/L and above: 14%

Of 374 pre-mitigation tests reported to CDC, not homes in this area.

Reported results by concentration band, Lancaster County, 2008 to 2017, laboratory: data table
Result bandTests MeasuredShare Measured
Under 2 pCi/L21056.1%
2 to 4 pCi/L11330.2%
4 pCi/L and above5113.6%
What these figures count

These are the 374 tests reported to CDC for Lancaster 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

Lancaster County, Compared

Lancaster County radon figures, compared

Calculated by Radon411

Lancaster County reports fewer high tests than South Carolina overall. 13.6% of its 374 tests over the 2008 to 2017 laboratory totals were at or above 4 pCi/L. That is 5.8 points below the 19.4% pooled from 46 South Carolina counties.

Ordered from highest share down, it comes 9th of 24 South Carolina counties with 30 or more tests for the same period. Nationally, every county with a figure for the same period pools to 35.7%; Lancaster County sits 22.1 points below it.

Next door, the shares run from 5.0% in Kershaw County to 13.6% in York County, with Union County, NC, Mecklenburg County, NC and Kershaw County below Lancaster County. Zone 3 on EPA's map (predicted average under 2 pCi/L) and a 13.6% share point the same way here.

Half the tests came in under 1.6 pCi/L and half over it; the single highest reached 13.1 pCi/L. The rest split 56.1% under 2 pCi/L and 30.2% from 2 to 4 (South Carolina: 57.4% and 23.1%).

CDC's ten-year totals for Lancaster County went from 260 tests (2005 to 2014) to 374 (2008 to 2017), the share going from 16.5% to 13.6%.

Lancaster County against South Carolina, the United States and nearby counties, 2008 to 2017, laboratory
AreaTestsAt or above 4 pCi/LMedianDifference from Lancaster County
Lancaster County37413.6%1.6 pCi/LThis county
South Carolina, pooled46 counties, pooled26,48119.4%Not pooled+5.8 points
United States, pooled2,661 counties, pooled2,013,54435.7%Not pooled+22.1 points
Oconee Countyhighest in the state2,46942.6%3.3 pCi/L+29.0 points
Florence Countylowest in the state590.0%0.7 pCi/L−13.6 points
Chester County, SCborders it1822.2%1.1 pCi/L+8.6 points
York County, SCborders it1,41213.6%1.2 pCi/LLevel
Union County, NCborders it83611.2%1.1 pCi/L−2.4 points
Mecklenburg County, NCborders it3,7538.5%0.9 pCi/L−5.1 points
Fairfield County, SCborders it277.4%0.9 pCi/L−6.2 points
Kershaw County, SCborders it605.0%0.7 pCi/L−8.6 points
Chesterfield County, SCborders it100.0%0.6 pCi/L−13.6 points
Where Lancaster County's reported results fell, 2008 to 2017, laboratory, beside South Carolina and the United States
ResultLancaster County testsLancaster County shareSouth Carolina shareU.S. shareAgainst South Carolina
Under 2 pCi/L21056.1%57.4%39.6%−1.3 points
2 to 4 pCi/L11330.2%23.1%24.7%+7.1 points
4 pCi/L and above5113.6%19.4%35.7%−5.8 points
Lancaster 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
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
Lexington County12 of 2459112.5%0.9 pCi/L
Sumter County13 of 244211.9%1.3 pCi/L
Anderson County14 of 241,73311.1%1.1 pCi/L
Lancaster 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 201737413.6%1.6 pCi/L13.1 pCi/L19.4%−1.9 points
2007 to 201632915.5%1.8 pCi/L13.1 pCi/L19.3%−1.6 points
2006 to 201529217.1%2.0 pCi/L13.1 pCi/L19.8%+0.6 points
2005 to 201426016.5%2.0 pCi/L13.1 pCi/L19.8%First on file

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

Lancaster County, Geology

The ground under Lancaster County

Predicted

Most of the ground under Lancaster County is one class on USGS's geologic map: 83.7% of its land is low radon potential, with 16.3% moderate. The map puts 61.7% of Lancaster County in the area it calls Carolina Slate Belt and 16.3% in Carolina and Charlotte Belt Granites, with 2 smaller areas beside them. USGS gives the first a radon index of 8, in the low band (5 to 8), and the second 11, in the moderate band (9 to 11).

USGS's geologic areas under Lancaster County
AreaThe rock, in USGS's wordsPotentialRadon indexShare of land
Carolina Slate Beltamphibolite, granitic gneiss, quartzite, muscovite schist, meta-argillite, metavolcanic rocks.Low861.7%
Carolina and Charlotte Belt GranitesGranite and granite gneissModerate1116.3%
Charlotte BeltBiotite gneiss and schist, metavolcanic rocks, mica gneiss.Low810.9%
Upper and Middle Coastal PlainTertiary coastal plain sandy and silty sediments and marsh deposits.Low810.7%

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

Lancaster County beside the ground around it

Across South Carolina 0.2% of the land is rated high; none of Lancaster County's is. Of the 7 counties that border it, 2 have more moderate-potential ground, York County the most at 21.0%.

Share of land by USGS radon potential: Lancaster County, the 7 counties bordering it and South Carolina
AreaEPA zoneLow potentialModerate potentialHigh potential
Lancaster CountyZone 383.7%16.3%None
Union County, NCZone 3100%NoneNone
Chester CountyZone 384.0%16.0%None
York CountyZone 279.0%21.0%None
Mecklenburg County, NCZone 3100%NoneNone
Kershaw CountyZone 388.7%11.3%None
Fairfield CountyZone 379.2%20.8%None
Chesterfield CountyZone 393.0%7.0%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

Lancaster County, Local resources

Radon testing and mitigation in Lancaster County

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

What it means

Lancaster County, Questions

Questions about radon in Lancaster County

Are radon levels high in Lancaster County?

Over the 2008 to 2017 laboratory totals, 13.6% of the radon tests reported to CDC for Lancaster County, South Carolina were at or above 4 pCi/L, and the median reported pre-mitigation result was 1.6 pCi/L. Of 24 South Carolina counties with 30 or more tests for the same period, 8 reported a higher share; pooled, the state comes to 19.4%.

Which counties border Lancaster County?

Lancaster County borders 7 counties: Union County, NC, Chester County, SC, York County, SC, Mecklenburg County, NC, Kershaw County, SC, Fairfield County, SC and Chesterfield County, SC.

Products

Lancaster County, Products

Testing a home in Lancaster County

In Lancaster County, 13.6% of 374 tests reported to CDC over the 2008 to 2017 laboratory totals reached 4 pCi/L, against 19.4% pooled across South Carolina. 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 Lancaster County.

Test kits and monitors3

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Best radon monitors for Lancaster County homes, compared

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Lancaster County, Bordering counties

Counties bordering Lancaster County

Calculated by Radon411

Lancaster County, Cities and towns

Cities and towns in Lancaster County

Lancaster County is growing: the Census Bureau puts it at 114,296 residents on July 1, 2025, up 18.3% from 96,589 in 2020. That works out to 208 people per square mile of land. No town dominates: Lancaster, the largest, has 9,623 residents, 8.4% of the total. Together its 4 incorporated places hold 11.9% of those residents; the other 88.1% live outside any of them. CDC's 374 reported tests for 2008 to 2017 work out to 3.3 per 1,000 residents (2025 estimate), close to South Carolina's 4.8.

From Lancaster to Heath Springs, CDC publishes no figure by town: each reads Lancaster County's.

The cities and towns in Lancaster County by residents, July 1, 2025
PlaceResidentsSince 2020Share of residents
Lancaster9,623+13.2%8.4%
Kershaw2,038+17.9%1.8%
Van Wyck1,065+21.2%0.9%
Heath Springs860+16.7%0.8%

4 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).

Lancaster County, Homes

Homes in Lancaster County

Lancaster County is a place of houses on their own lots: 76% of its 42,696 homes are detached single-family houses, against 64% across South Carolina. Half of its homes were built before 1998, close to South Carolina's 1991: 13% date from before 1960 and 48% from 2000 or later. Owners live in 83% of the occupied homes (South Carolina: 71%), so for most households a test and a fix are their own to order.

Homes in Lancaster County, South Carolina, 2019 to 2023
HomesLancaster CountySouth Carolina
Housing units42,6962,401,638
Detached houses76%64%
In buildings of 5 or more5%13%
Mobile homes13%15%
Built before 196013%13%
Built since 200048%35%
Middle year built19981991
Owner-occupied83%71%

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