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Radon in Northumberland County, Pennsylvania

Northumberland County, Pennsylvania, is in EPA radon Zone 1: predicted average indoor radon screening level greater than 4 pCi/L (highest potential). Radon laboratories reported 658 building tests here for 2008 to 2017: median 5.6 pCi/L, with 59.5% at or above EPA's 4 pCi/L action level (Pennsylvania 41.1%, US 36.5%). Pennsylvania state records have 12,729 test results on file for the county, median 2.9 pCi/L, 40% at or above 4 pCi/L.

Zone 1
EPA radon zone (1993 county map)
5.6
median lab test, pCi/L (2008-2017)
59.5%
of lab tests at or above 4 pCi/L
658
buildings tested by labs, 2008-2017

Radon test results in Northumberland County

Radon test results on file for Northumberland County, PA, with state and national comparison
Test resultsPeriodTestsTypical result4 pCi/L or more
Radon testing laboratories2008-2017658median 5.6 pCi/L59.5%
Pennsylvania state records, every reported test1986 to 2026-0712,729median 2.9 pCi/L40%
Pennsylvania, all counties (labs)2008-2017173,284n/a41.1%
United States (labs)2008-20171,408,802n/a36.5%

Test results describe buildings whose owners chose to test and whose results reached the lab or agency, not a random sample; small counts swing widely. State and US shares are computed from county counts and percents. The laboratory data comes from national radon testing laboratories and supplements EPA's zone map.

Radon levels by ZIP code in Northumberland County

Pennsylvania state results for the ZIP codes with 10 or more tests reported in Northumberland County, 1986 to 2026-07.

ZIP codeTestsMedian4 pCi/L or more
170172275.8 pCi/L61.2%
17730121.9 pCi/L33.3%
17749226.1 pCi/L54.5%
17756278.8 pCi/L59.3%
177722822.0 pCi/L31.9%
177771,0163.2 pCi/L41.1%
178011,8622.4 pCi/L36.6%
178215363.0 pCi/L43.1%
178231016.8 pCi/L67.3%
178241,1414.8 pCi/L55.6%
178302605.2 pCi/L56.5%
17832552.8 pCi/L36.4%
178344803.6 pCi/L45.4%
17836216.3 pCi/L61.9%
17837152.1 pCi/L33.3%
17840171.7 pCi/L5.9%
178472,0213.0 pCi/L38.8%
17850312.0 pCi/L25.8%
178517661.1 pCi/L12.3%
178571,7842.9 pCi/L39%
178603028.3 pCi/L67.2%
17865133.0 pCi/L30.8%
178667362.4 pCi/L32.1%
17867158.2 pCi/L60%
178682263.5 pCi/L42%
17870103.2 pCi/L30%
178725842.1 pCi/L34.1%
17877192.2 pCi/L31.6%
178811292.9 pCi/L38.8%

Radon in nearby counties

CountyEPA zoneLab tests4 pCi/L or more
Montour County, PAZone 116561.6%
Union County, PAZone 132062.9%
Snyder County, PAZone 130664.8%
Columbia County, PAZone 151851%
Schuylkill County, PAZone 12,14455.7%
Dauphin County, PAZone 13,90255%

The six counties with the nearest centers.

What to do about radon in Northumberland County

Test the building. EPA recommends fixing a home at 4 pCi/L or more and considering a fix between 2 and 4 pCi/L, and says there is no known safe level of exposure. The state environmental protection agency runs the state's radon program.

Buying here? The Environmental Records Report lists this county's radon zone and test results with the flood zone, mapped faults, power lines and federal contamination records near the address.

Check one Northumberland County address

Environmental Records Report, $29. PDF and JSON, usually ready in about a minute.

Radon in Northumberland County: questions

What is the radon level in Northumberland County?

The median of the 658 laboratory tests reported for Northumberland County (2008 to 2017) was 5.6 pCi/L, and 59.5% of them were at or above 4 pCi/L. Pennsylvania's 12,729 state results have a median of 2.9 pCi/L. These are results of tested buildings; a single home can be far above or below them.

Is Northumberland County in radon Zone 1?

Yes. EPA's 1993 Map of Radon Zones puts Northumberland County in Zone 1, the counties with a predicted average indoor radon screening level above 4 pCi/L.

How does radon in Northumberland County compare with Pennsylvania?

59.5% of laboratory tests in Northumberland County were at or above 4 pCi/L for 2008 to 2017, against 41.1% across Pennsylvania (173,284 tests) and 36.5% nationally. 49 of Pennsylvania's 67 counties are in Zone 1.

Should I test for radon in Northumberland County?

Yes. EPA recommends testing every home whatever its zone: "This map should not be used to determine if individual homes need to be tested." Fix the home at 4 pCi/L or more and consider a fix between 2 and 4 pCi/L; EPA says there is no known safe level of radon exposure.

More for Northumberland County

Other free hazard lookups

All of these, plus wetlands, FEMA hazard ratings and the federal contamination lists, are in the Environmental Records Report for any US address ($29).

Radon in every Pennsylvania county · Radon map of every state

Data compiled 2026-10-20. County FIPS 42097. County-level screening information, not a radon measurement of any building.