43%tests ≥ 4 pCi/L
100,651tests on record
3.2median pCi/L
Zone 1EPA zone (1993 prediction)

Test results in Northampton County

ResultShareEPA guidance
Below 2 pCi/L36%Below EPA's levels
2 to 4 pCi/L20%Consider fixing
4 pCi/L or more43%EPA recommends fixing

What the data shows

Where Northampton County sits among Pennsylvania's 67 counties with dataEach dot is a county's share of tests at or above 4 pCi/L · Pennsylvania county radon test results, 1986–2026
0%20%40%60%

How Northampton County compares

Northampton County has the highest share of high results among its neighboursShare of tests at or above 4 pCi/L · Pennsylvania county radon test results, 1986–2026 · whisker: 95% range
Northampton County43%Lehigh County43%Carbon County43%Monroe County36%Bucks County25%Pennsylvania 34%
Data table
AreaTests ≥ 4 pCi/LTests
Northampton County43%100,651
Lehigh County43%110,236
Carbon County43%14,068
Monroe County36%62,336
Bucks County25%293,407
Pennsylvania (67 counties)34%3,356,893

Same source as Northampton County. Other bordering counties: Warren County, New Jersey.

What it means for your home

About 1 in 2 results in Northampton County were at or above 4 pCi/L, where the EPA recommends a fix. Only a test shows your own home's level.

Levels in pCi/L from the EPA. The WHO reference level is 100 Bq/m³, about 2.7 pCi/L.

Test your home

Start with a short-term test (2–90 days) and confirm a result of 4 pCi/L or more with a second test. EPA guide

Sponsored: we earn a commission on purchases through these links. We haven't tested Airthings monitors yet.

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Fixing high radon

No local job records yet. National range: $800–$2,500, average $1,200 (EPA, 2003). Cost guide →

Pennsylvania licenses radon mitigators. Source

Buying or selling here

Pennsylvania's required Seller's Property Disclosure Statement asks whether the seller knows of hazardous substances on the property, including radon (49 Pa. Code § 35.335a). Source

Checked against the official text on 2026-11-03. Not legal advice.

About this data

Source: Pennsylvania county radon test results (Pennsylvania Department of Environmental Protection). Period: 1986–2026. Tests: 100,651. Read the methodology →

These are voluntary and real-estate tests, not a random sample of homes, so they describe tested homes rather than every home.

About this page

Published by Ray Roman, editor of Radon by County. Figures are loaded from the cited source and spot-checked against it. Editorial policy · About us