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Radon in Lewis County, New York

Lewis County, New York, is in EPA radon Zone 2: predicted average indoor radon screening level from 2 to 4 pCi/L (moderate potential). Radon laboratories reported 62 building tests here for 2008 to 2017: median 1.4 pCi/L, with 20.2% at or above EPA's 4 pCi/L action level (New York 24.2%, US 36.5%). New York state health records show 31.2% of 125 basement kit tests at or above 4 pCi/L.

Zone 2
EPA radon zone (1993 county map)
1.4
median lab test, pCi/L (2008-2017)
20.2%
of lab tests at or above 4 pCi/L
62
buildings tested by labs, 2008-2017

Radon test results in Lewis County

Radon test results on file for Lewis County, NY, with state and national comparison
Test resultsPeriodTestsTypical result4 pCi/L or more
Radon testing laboratories2008-201762median 1.4 pCi/L20.2%
New York radon program20221median 1.0 pCi/L0%
State health records, basement kit tests1987 on125average 6.8 pCi/L31.2%
State health records, first-floor kit tests1987 on57average 2.5 pCi/L22.8%
New York, all counties (labs)2008-201765,893n/a24.2%
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 by town in Lewis County

New York state basement kit results by town since 1987, towns with the most tests first.

Town, village or cityBasement testsAverage4 pCi/L or more
Lowville293.5 pCi/L37.9%
Leyden203.4 pCi/L25%
Diana141.9 pCi/L7.1%
Croghan104.6 pCi/L30%
Greig85.2 pCi/L25%
Lyonsdale86.3 pCi/L25%
Denmark740.4 pCi/L57.1%
Turin719.2 pCi/L42.9%
W. Turin57.3 pCi/L60%
Watson53.0 pCi/L40%
Martinsburg44.6 pCi/L50%
Harrisburg35.6 pCi/L33.3%
Lewis31.1 pCi/L0%
New Bremen21.6 pCi/L0%

Radon in nearby counties

CountyEPA zoneLab tests4 pCi/L or more
Herkimer County, NYZone 325541.5%
Jefferson County, NYZone 260916%
Oneida County, NYZone 21,45834.6%
Oswego County, NYZone 245215.2%
Hamilton County, NYZone 3927.3%
St. Lawrence County, NYZone 212113.2%

The six counties with the nearest centers.

What to do about radon in Lewis 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 health department 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 Lewis County address

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

Radon in Lewis County: questions

What is the radon level in Lewis County?

The median of the 62 laboratory tests reported for Lewis County (2008 to 2017) was 1.4 pCi/L, and 20.2% of them were at or above 4 pCi/L. New York state basement kits average 6.8 pCi/L. These are results of tested buildings; a single home can be far above or below them.

Is Lewis County in radon Zone 1?

No. EPA's 1993 map puts Lewis County in Zone 2 (predicted average indoor radon screening level from 2 to 4 pCi/L (moderate potential)). EPA says homes in every zone can have high radon and should be tested.

How does radon in Lewis County compare with New York?

20.2% of laboratory tests in Lewis County were at or above 4 pCi/L for 2008 to 2017, against 24.2% across New York (65,893 tests) and 36.5% nationally. 34 of New York's 62 counties are in Zone 1.

Should I test for radon in Lewis 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 Lewis 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 New York county · Radon map of every state

Data compiled 2026-10-20. County FIPS 36049. County-level screening information, not a radon measurement of any building.