Lewis County, NY Radon Zone Data

Lewis County, NY radon potential

EPA places Lewis County in Zone 2 - Moderate Potential — a predicted county-wide average indoor radon level between 2 and 4 pCi/L, based on the geology, soil and aerial radioactivity data behind EPA's national map. Nationally that's the 49th percentile for radon potential — Lewis County outranks 49% of every county EPA has rated.

How Lewis County compares

Lewis County, New York is home to about 26,570 people across 1,276.309 square miles. Averaged across its land area, Lewis County runs about 21 people per square mile. Within its own EPA zone, Lewis County is bigger by population than 49% of the counties that share it. Geologically, Lewis County is grouped into EPA Region 2 alongside 82 other counties that share its rock and soil setting.

What this actually means for a house in Lewis County

Neither at the 4 pCi/L action level nor down at the roughly 1.3 pCi/L national indoor norm, Lewis County's Zone 2 prediction lands in the gap between the two. A county-wide moderate average, like Lewis County's, can still hide a specific house well above or below it — testing is what actually answers the question.

Next steps for a home in Lewis County

A short-term test kit is the standard first step and typically costs far less than mitigation itself. If a test comes back at or above 4 pCi/L, a radon mitigation system for a typical home runs roughly $800–$2,500 (around $1,200 for a common single-family install), driven mainly by foundation type, not by county.

Find New York's state radon program

For Lewis County, an ongoing number beats a one-time test - a Airthings radon monitor tracks Lewis County's levels over time. RadonZoneCheck earns a commission there, at no extra cost to you. Use code RADONZONE-10OFF at checkout for 10% off.

Where Lewis County's figures come from

Every figure on this page traces to EPA's own Map of Radon Zones and Census data, documented in the methodology guide. Whatever zone Lewis County carries, the zone explainer covers what it does and doesn't tell you about any one house.