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Radon Levels in Harnett County, North Carolina

EPA puts Harnett County in Zone 3, its lowest radon zone, and only 2 radon tests from it are on file with CDC (2022). 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

    0.6%

    22.0 pts below NC

    Harnett
    0.6%
    NC
    22.6%

    181 tests, 2008 to 2017

  • Median result

    0.6pCi/L

    Below action level

    Harnett
    0.6 pCi/L
    EPA
    4.0 pCi/L

    Midpoint of the tests, 2008 to 2017

  • Tests reported

    181

    50th of 75 by tests

    Harnett
    181
    Wake
    9,694

    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 NC

    69 of 75

    Lowest quarter

    Harnett
    0.6%
    Transylvania
    47.8%

    By share, of 75 with 30+ tests

Read a result for Harnett County

Starts at Harnett County's median, 0.6 pCi/L

0.6pCi/L

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

EPA’s reading of 0.6 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. Harnett County's median reported result, 2008 to 2017.

Interpret this reading

The data

Harnett County, At a glance

Harnett County at a glance

Predicted: EPA radon zone

EPA Zone 3: lower predicted potential

is EPA's lowest class, and its forecast for Harnett 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 88% of the county's area

Predicted: EPA Map of Radon Zones

Measured: tests reported to CDC

Radon tests reported for Harnett County, 2022

Share of reported tests at or above 4 pCi/L, by year, Harnett County
Share of reported tests at or above 4 pCi/L, by year, Harnett County
YearShare of reported tests at or above 4 pCi/L
201443.1%
20200.0%
20210.0%
20220.0%

2022: 0.0%. Across these years the share ran from 0.0% to 43.1%. Each column counts radon tests reported to CDC that year, not homes.

What these figures count

Only 2 tests were reported to CDC for Harnett County over 2022, and tests are often run on homes being sold or already suspected of a problem: so few describe neither the county nor 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

Harnett County, Compared

Harnett County radon figures, compared

Calculated by Radon411

Only 1 of 181 radon tests reported for Harnett County over the 2008 to 2017 laboratory totals reached 4 pCi/L (0.6%). The median result, 0.6 pCi/L, sits below 2, well under EPA's 4 pCi/L action level, and the top reported result was 7.1 pCi/L.

The newest figure, in 2022, counts only 2 tests (0.0% at or above 4 pCi/L), too few to compare, so this reading uses the 181-test figure.

Across 99 North Carolina counties pooled together, 22.6% of tests reached that level, so Harnett County runs 22.0 points below its state. Against the national pool of 35.7%, the gap is 35.1 points lower. Its place in the state: 69th of 75 North Carolina counties with 30 or more tests for the same period.

Zone 3 on EPA's map (predicted average under 2 pCi/L) and a 0.6% share point the same way here. Of 6 neighbours with a figure, all 6 reported a larger share at or above 4 pCi/L; the spread is 1.1% (Lee County) to 19.2% (Moore County).

Below the action level, 164 tests (90.6%) came in under 2 pCi/L, against 55.6% statewide, and 16 tests (8.8%) fell between 2 and 4, against 21.8% statewide. USGS geology rates 88% of the county's land low radon potential.

The busiest year on file was 2014, with 123 tests reported; the quietest, 2022, had 2.

Harnett County against North Carolina, the United States and nearby counties, 2008 to 2017, laboratory
AreaTestsAt or above 4 pCi/LMedianDifference from Harnett County
Harnett County1810.6%0.6 pCi/LThis county
North Carolina, pooled99 counties, pooled73,13922.6%Not pooled+22.0 points
United States, pooled2,661 counties, pooled2,013,54435.7%Not pooled+35.1 points
Transylvania Countyhighest in the state3,86247.8%3.7 pCi/L+47.2 points
Nash Countylowest in the state300.0%0.2 pCi/L−0.6 points
Moore County, NCborders it9919.2%1.3 pCi/L+18.6 points
Chatham County, NCborders it58710.9%1.1 pCi/L+10.3 points
Wake County, NCborders it9,6949.6%1.0 pCi/L+9.0 points
Johnston County, NCborders it6688.2%0.7 pCi/L+7.6 points
Cumberland County, NCborders it1601.9%0.7 pCi/L+1.3 points
Lee County, NCborders it931.1%0.9 pCi/L+0.5 points
Sampson County, NCborders it130.0%0.6 pCi/L−0.6 points
Where Harnett County's reported results fell, 2008 to 2017, laboratory, beside North Carolina and the United States
ResultHarnett County testsHarnett County shareNorth Carolina shareU.S. shareAgainst North Carolina
Under 2 pCi/L16490.6%55.6%39.6%+35.0 points
2 to 4 pCi/L168.8%21.8%24.7%−13.0 points
4 pCi/L and above10.6%22.6%35.7%−22.0 points
Harnett County ranked among the 75 North 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
Scotland County64 of 75313.2%1.0 pCi/L
Onslow County65 of 751882.7%0.5 pCi/L
Cumberland County66 of 751601.9%0.7 pCi/L
Lee County67 of 75931.1%0.9 pCi/L
Pitt County68 of 751011.0%0.1 pCi/L
Harnett County69 of 751810.6%0.6 pCi/L
Craven County70 of 751090.0%0.2 pCi/L
Brunswick County70 of 75620.0%0.5 pCi/L
Richmond County70 of 75520.0%0.6 pCi/L
Carteret County70 of 75410.0%0.1 pCi/L
Columbus County70 of 75310.0%0.1 pCi/L
Harnett County radon tests by year, against North Carolina's pooled share
YearTestsAt or above 4 pCi/LMedianHighestNorth Carolina, pooledChange from the row before
202220.0%1.0 pCi/L1.0 pCi/L10.7%Level
2021230.0%0.1 pCi/L2.0 pCi/L14.9%Level
2020240.0%0.1 pCi/L3.2 pCi/L21.1%−43.1 points
201412343.1%2.7 pCi/L9.3 pCi/L21.9%First on file

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

Harnett County, Geology

The ground under Harnett County

Predicted

Most of the ground under Harnett County is one class on USGS's geologic map: 88.1% of its land is low radon potential, with 11.9% moderate. The map puts 63.9% of Harnett County in the area it calls Inner Coastal Plain and 24.3% in Eastern Slate Belt, with one smaller area beside them. USGS gives both a radon index of 8, in the low band (5 to 8).

USGS's geologic areas under Harnett County
AreaThe rock, in USGS's wordsPotentialRadon indexShare of land
Inner Coastal PlainFossiliferous clay and sand, shelly sand, sandy marl, and limestone.Low863.9%
Eastern Slate BeltProterozoic to Cambrian metamudstone and argillite, interbedded with metamorphosed sandstone, conglomerate, and volcanic rock.Low824.3%
Raleigh BeltProterozoic through Cambrian biotite gneiss and mica schist.Moderate1111.9%

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

Harnett County beside the ground around it

Across North Carolina 1.3% of the land is rated high; none of Harnett County's is. Of the 7 counties that border it, 2 have more moderate-potential ground, Wake County the most at 79.4%.

Share of land by USGS radon potential: Harnett County, the 7 counties bordering it and North Carolina
AreaEPA zoneLow potentialModerate potentialHigh potential
Harnett CountyZone 388.1%11.9%None
Lee CountyZone 389.3%10.7%None
Cumberland CountyZone 3100%NoneNone
Wake CountyZone 220.6%79.4%None
Johnston CountyZone 369.1%30.9%None
Chatham CountyZone 398.6%1.4%None
Moore CountyZone 3100%NoneNone
Sampson CountyZone 3100%NoneNone
North Carolina100 counties, pooled by land areaVaries64.8%33.0%1.3%

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

Local help

Harnett County, Local resources

Radon testing and mitigation in Harnett County

What North Carolina's program says
Licensing of radon professionals
The North Carolina Radon Program is presently developing a Radon Proficiency Program as directed by Session Law 2023-91 House Bill 782 .

What it means

Harnett County, Questions

Questions about radon in Harnett County

Are radon levels high in Harnett County?

In 2022, 0.0% of the radon tests reported to CDC for Harnett County, North Carolina were at or above 4 pCi/L, and the median reported pre-mitigation result was 1.0 pCi/L. Of 75 North Carolina counties with 30 or more tests for the same period, 68 reported a higher share; pooled, the state comes to 22.6%.

Which counties border Harnett County?

Harnett County borders 7 counties: Lee County, Cumberland County, Wake County, Johnston County, Chatham County, Moore County and Sampson County.

Products

Harnett County, Products

Testing a home in Harnett County

In Harnett County, 0.6% of 181 tests reported to CDC over the 2008 to 2017 laboratory totals reached 4 pCi/L, against 22.6% pooled across North 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 Harnett County.

Test kits and monitors3

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Best radon monitors for Harnett County homes, compared

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Harnett County, Bordering counties

Counties bordering Harnett County

Calculated by Radon411

Harnett County, Cities and towns

Cities and towns in Harnett County

Harnett County is growing: the Census Bureau puts it at 150,137 residents on July 1, 2025, up 12.3% from 133,716 in 2020. That works out to 252 people per square mile of land. Fuquay-Varina, the largest place on its list (48,536 residents in all), extends beyond Harnett County, so no share of the total is worked out for it. Reported testing is thin here: 181 tests over 2008 to 2017, or 1.2 for every 1,000 residents (2025 estimate), where North Carolina as a whole comes to 6.5.

From Fuquay-Varina to Broadway, CDC publishes no figure by town: each reads Harnett County's.

The cities and towns in Harnett County by residents, July 1, 2025
PlaceResidentsSince 2020Share of residents
Fuquay-Varinaextends beyond Harnett County48,536+40.4%Counted whole
Angierextends beyond Harnett County9,410+64.5%Counted whole
Dunn8,814+4.4%5.9%
Lillington5,040+3.7%3.4%
Erwin4,956+9.9%3.3%
Bensonextends beyond Harnett County4,660+16.3%Counted whole
Coats2,370+10.4%1.6%
Broadwayextends beyond Harnett County1,380+8.4%Counted whole

8 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 Harnett County is counted whole, so it has no share.

Harnett County, Homes

Homes in Harnett County

Of Harnett County's 54,051 homes, 70% are detached houses, against 65% across North Carolina; 19% are mobile homes. Half of its homes were built before 1996, close to North Carolina's 1990: 11% date from before 1960 and 42% from 2000 or later. 69% of occupied homes are lived in by their owner (North Carolina: 66%); in the rest a tenant can run a test, but a fix is the landlord's to make.

Homes in Harnett County, North Carolina, 2019 to 2023
HomesHarnett CountyNorth Carolina
Housing units54,0514,815,195
Detached houses70%65%
In buildings of 5 or more3%14%
Mobile homes19%11%
Built before 196011%14%
Built since 200042%33%
Middle year built19961990
Owner-occupied69%66%

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