Long-term kit
RL416 long-term radon test kit, lab fee included
- Lab fee included
Method: Alpha track
In home: 90 days to 12 months
Locations and reports
Radon Levels in Northampton County, Pennsylvania
EPA puts Northampton County in Zone 1, its highest radon zone, and high results are common there: 41.3% of the 3,434 radon tests reported to CDC (2020) came back at or above 4 pCi/L. Homes with elevated levels occur in all three zones, so only a test measures yours.
Data checked By Radon411Methodology
Share at 4+ pCi/L
41.3%
11.0 pts above PA
- Northampton
- 41.3%
- PA
- 30.3%
3,434 tests, 2020
Median result
2.9pCi/L
Below action level
- Northampton
- 2.9 pCi/L
- EPA
- 4.0 pCi/L
Midpoint of the tests, 2020
Tests reported
3,434
9th of 63 by tests
- Northampton
- 3,434
- Montgomery
- 10,508
Reported to CDC before any fix, 2020
EPA radon zone
Zone 1
Highest potential
- Zone 1
- 2
- 3
1 highest, 3 lowest
EPA predicts over 4 pCi/L indoors
Rank in PA
29 of 63
Middle half
- Northampton
- 41.3%
- Perry
- 57.7%
By share, of 63 with 30+ tests
Read a result for Northampton County
Starts at Northampton County's median, 2.9 pCi/L
EPA’s own thresholds; the figures are the area’s, never this home’s.
EPA’s reading of 2.9 pCi/L
Between 2 and 4 pCi/L
- Under 20 to 1.9 pCi/L
- 2 to 4consider a fix
- 4 and aboveEPA says fix it
This result is between 2 and 4 pCi/L. EPA recommends considering a fix when the level is between 2 and 4 pCi/L. Northampton County's median reported result, 2020.
The data
Northampton County, At a glance
Northampton County at a glance
Predicted: EPA radon zone
EPA Zone 1: highest predicted potential
EPA puts all of Northampton County in
USGS geologic potential: High across 100% of the county's area
Predicted: EPA Map of Radon Zones
Measured: tests reported to CDC
Radon tests reported for Northampton County, 2020
| Year | Share of reported tests at or above 4 pCi/L |
|---|---|
| 2014 | 48.0% |
| 2015 | 45.2% |
| 2016 | 38.2% |
| 2017 | 44.3% |
| 2018 | 41.4% |
| 2019 | 39.1% |
| 2020 | 41.3% |
2020: 41.3%. Across these years the share ran from 38.2% to 48.0%. Each column counts radon tests reported to CDC that year, not homes.
What these figures count
These are the 3,434 tests reported to CDC for Northampton County over 2020, many from homes being sold or already suspected of a problem: they describe the county's reported tests, not this house.
Measured: CDC tracking data. Figure above: 2020. Measured data period: 2005 to 2020 (every CDC figure on file).
Northampton County, Compared
Northampton County radon figures, compared
Calculated by Radon411In Northampton County, about 4 in 10 reported tests in 2020 (1,417 of 3,434) were at or above EPA's action level. Against the national pool of 25.5%, the gap is 15.8 points higher. Across 67 Pennsylvania counties pooled together, 30.3% of tests reached that level, so Northampton County runs 11.0 points above its state.
Of 5 neighbours with a figure, none reported a larger share at or above 4 pCi/L; the spread is 23.2% (Bucks County) to 40.6% (Carbon County). By share, Northampton County is 29th of 63 Pennsylvania counties with 30 or more tests for the same period.
Year by year, 2014 opened at 48.0% and 2020 closed at 41.3% (down 6.7 points), with 2014 the high at 48.0%. Half the tests came in under 2.9 pCi/L and half over it; the single highest reached 238.3 pCi/L. Below the action level, 1,287 tests (37.5%) came in under 2 pCi/L, against 44.3% statewide, and 730 tests (21.3%) fell between 2 and 4, against 25.4% statewide.
Zone 1 on EPA's map (predicted average above 4 pCi/L) and a 41.3% share point the same way here. USGS geology rates 100% of the county's land high radon potential.
The busiest year on file was 2016, with 4,455 tests reported; the quietest, 2014, had 2,412.
Northampton CountyPennsylvania, pooled
41.3% % of tests30.3% % of tests
| Year | Tests | Northampton County, at or above 4 pCi/L | Pennsylvania, pooled |
|---|---|---|---|
| 2014 | 2,412 | 48.0% | 36.1% |
| 2015 | 3,602 | 45.2% | 37.8% |
| 2016 | 4,455 | 38.2% | 34.4% |
| 2017 | 3,416 | 44.3% | 35.1% |
| 2018 | 2,934 | 41.4% | 30.5% |
| 2019 | 3,777 | 39.1% | 31.4% |
| 2020 | 3,434 | 41.3% | 30.3% |
Pooled shares: Radon411's sum of CDC's county counts for one period.
Northampton County, State data
Pennsylvania's own radon test data
MeasuredWhat Pennsylvania's own agencies publish about radon tests in Northampton County, with their period. These are not CDC's figures and are never added to them.
MeasuredState figures, not CDC's
What Pennsylvania DEP reports for the ZIP codes in Northampton County
Pennsylvania DEP publishes its figures by ZIP code, not by county. These are the 26 ZIP codes that lie wholly or partly in Northampton County, each with the state's own figures for it. Period: Period not stated by DEP.
| ZIP code | What the state reports |
|---|---|
| 18013 | Basement: average 12.7 pCi/L, 2,375 tests; First floor: average 5.1 pCi/L, 243 tests |
| 18014 | Basement: average 17.0 pCi/L, 1,994 tests; First floor: average 7.8 pCi/L, 262 tests |
| 18015 | Basement: average 6.9 pCi/L, 4,055 tests; First floor: average 4.2 pCi/L, 686 tests |
| 18017 | Basement: average 6.6 pCi/L, 9,647 tests; First floor: average 3.8 pCi/L, 1,380 tests |
| 18018 | Basement: average 5.8 pCi/L, 4,815 tests; First floor: average 3.0 pCi/L, 561 tests |
| 18020 | Basement: average 6.5 pCi/L, 4,749 tests; First floor: average 4.5 pCi/L, 299 tests |
| 18032 | Basement: average 7.1 pCi/L, 928 tests; First floor: average 3.5 pCi/L, 85 tests |
| 18035 | Basement: average 20.0 pCi/L, 61 tests; First floor: figures not shown |
| 18038 | Basement: average 19.5 pCi/L, 443 tests; First floor: average 7.5 pCi/L, 53 tests |
| 18040 | Basement: average 7.1 pCi/L, 4,595 tests; First floor: average 5.0 pCi/L, 293 tests |
| 18042 | Basement: average 8.5 pCi/L, 6,430 tests; First floor: average 4.3 pCi/L, 932 tests |
| 18045 | Basement: average 6.5 pCi/L, 6,332 tests; First floor: average 4.2 pCi/L, 578 tests |
| 18055 | Basement: average 7.9 pCi/L, 2,480 tests; First floor: average 4.0 pCi/L, 323 tests |
| 18063 | Basement: average 8.7 pCi/L, 74 tests; First floor: figures not shown |
| 18064 | Basement: average 12.1 pCi/L, 6,535 tests; First floor: average 6.3 pCi/L, 622 tests |
| 18067 | Basement: average 11.4 pCi/L, 2,805 tests; First floor: average 4.9 pCi/L, 375 tests |
| 18072 | Basement: average 13.3 pCi/L, 1,036 tests; First floor: average 6.0 pCi/L, 103 tests |
| 18077 | Basement: average 8.6 pCi/L, 729 tests; First floor: average 4.0 pCi/L, 135 tests |
| 18083 | Basement: average 6.8 pCi/L, 111 tests; First floor: figures not shown |
| 18085 | Basement: average 7.8 pCi/L, 161 tests; First floor: figures not shown |
| 18086 | Basement: average 18.2 pCi/L, 40 tests; First floor: figures not shown |
| 18088 | Basement: average 19.3 pCi/L, 1,307 tests; First floor: average 9.0 pCi/L, 127 tests |
| 18091 | Basement: average 14.4 pCi/L, 853 tests; First floor: average 7.5 pCi/L, 67 tests |
| 18109 | Basement: average 5.1 pCi/L, 872 tests; First floor: average 2.7 pCi/L, 74 tests |
| 18343 | Basement: average 6.9 pCi/L, 595 tests; First floor: average 3.5 pCi/L, 53 tests |
| 18351 | Basement: average 7.0 pCi/L, 54 tests; First floor: figures not shown |
- DEP's report gives the number of tests, the highest result and the average result for each floor tested; it states no period.
- DEP says the smartest thing to do is to test your home for radon, no matter where you live.
- A ZIP code that crosses the county line is listed whole; its figures cover all of it.
Measured: Pennsylvania DEP data, Period not stated by DEP.
Northampton County, Geology
The ground under Northampton County
PredictedUSGS's geologic map puts all of Northampton County's mapped land in one class: high radon potential. The map puts 83.2% of Northampton County in the area it calls Great Valley Section and 10.6% in Highlands, with 2 smaller areas beside them. USGS gives both a radon index of 15, in the high band (12 to 17).
| Area | The rock, in USGS's words | Potential | Radon index | Share of land |
|---|---|---|---|---|
| Great Valley Section | Sandstone, shale and siltstone. | High | 15 | 83.2% |
| Highlands | Glacial deposits, granite, pegmatites, and gneiss. | High | 15 | 10.6% |
| Appalachian Mountain Section | Paleozoic sandstone, shale, and limestone. | High | 12 | 5.1% |
| Newark Basin | Gray shale and fluvial sandstone. | High | 12 | 0.7% |
Names, descriptions and indexes: U.S. Geological Survey, Geologic Radon Potential Map (2025). Shares: Radon411, from the map cut to the boundary.
Northampton County beside the ground around it
Northampton County has more high-potential ground than Pennsylvania as a whole: 99.8% of its land against 70.4%. Of the 5 counties that border it, 1 has more high-potential ground, Lehigh County the most at 100%.
The map rates the ground, not the air in any home.
Local help
Northampton County, Local resources
Radon testing and mitigation in Northampton County
Listed radon businesses with an address in Northampton County:
- Radon DivisionRadon Division, run by Department of Environmental Protection, licenses or certifies radon professionals and offers free or discounted test kits, and answers questions about testing and mitigation in Pennsylvania.Visit the program’s page(opens in a new tab)
- Free and low-cost kitsThe program says:
Through an EPA-funded program, hospitals give parents of newborn children a packet of information which includes a coupon for a free radon test kit from the DEP.
- Compare kits
- Professionals in Pennsylvania151 professionals are listed in Pennsylvania.
Listed radon professionals by town: Easton, Nazareth
What Pennsylvania's program says
- Phone
- 800-237-2366
- Licensing of radon professionals
The Radon Certification Act requires DEP to establish by regulation, a certification program for persons conducting radon gas and radon progeny testing, laboratory analysis and mitigation of radon contamination in buildings.
What it means
Northampton County, Questions
Questions about radon in Northampton County
Are radon levels high in Northampton County?
In 2020, 41.3% of the radon tests reported to CDC for Northampton County, Pennsylvania were at or above 4 pCi/L, and the median reported pre-mitigation result was 2.9 pCi/L. Of 63 Pennsylvania counties with 30 or more tests for the same period, 28 reported a higher share; pooled, the state comes to 30.3%.
Which counties border Northampton County?
Northampton County borders 5 counties: Lehigh County, PA, Monroe County, PA, Carbon County, PA, Warren County, NJ and Bucks County, PA.
Products
Northampton County, Products
Testing a home in Northampton County
In Northampton County, 41.3% of 3,434 tests reported to CDC in 2020 reached 4 pCi/L, against 30.3% pooled across Pennsylvania. In Zone 1 the year-round level in Northampton County is the one to know: a long-term test (more than 90 days) or a monitor, with a short-term kit for a first answer.
Test kits and monitors3
See every kit and monitor
Monitor
RadonScan-Plus USB-powered radon monitor with Wi-Fi
- C-NRPP 2024/25: Not included
- Plug-in
- Wi-Fi
- Alarm
- Screen, app
First reading: Within 5 minutes
Short-term kit
RA100 short-term liquid scintillation radon test kit
- Lab fee extra
Method: Liquid scintillation
In home: 48 to 96 hours
- See every kit and monitor Test kits and monitors
Test kits and monitors: 1 of 3
Northampton County is in EPA Zone 1, the highest predicted radon potential. Best radon monitors for Zone 1 counties like Northampton County
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Northampton County, Bordering counties
Counties bordering Northampton County
Calculated by Radon411- Radon levels in Carbon County, PAEPA zone 1
40.6%at or above 4 pCi/L
Median 3.0 pCi/L · 438 tests · 0.7 points below Northampton County
- Radon levels in Lehigh County, PAEPA zone 1
39.8%at or above 4 pCi/L
Median 2.7 pCi/L · 3,103 tests · 1.5 points below Northampton County
- Radon levels in Monroe County, PAEPA zone 1
30.7%at or above 4 pCi/L
Median 2.1 pCi/L · 1,649 tests · 10.6 points below Northampton County
- Radon levels in Warren County, NJEPA zone 1
28.1%at or above 4 pCi/L
Median 1.9 pCi/L · 3,473 tests · 13.2 points below Northampton County
- Radon levels in Bucks County, PAEPA zone 1
23.2%at or above 4 pCi/L
Median 2.0 pCi/L · 7,066 tests · 18.1 points below Northampton County
Northampton County, Cities and towns
Cities and towns in Northampton County
The Census Bureau estimates 324,411 residents in Northampton County for July 1, 2025, 11,602 more than in 2020 (+3.7%). That works out to 877 people per square mile of land. Bethlehem, the largest place on its list (79,644 residents in all), extends beyond Northampton County, so no share of the total is worked out for it. CDC's 3,434 reported tests for 2020 work out to 10.6 per 1,000 residents (2025 estimate), close to Pennsylvania's 7.2.
From Bethlehem to Chapman, CDC publishes no figure by town: each reads Northampton County's.
| Place | Residents | Since 2020 | Share of residents |
|---|---|---|---|
| Bethlehemextends beyond Northampton County | 79,644 | +5.2% | Counted whole |
| Easton | 30,402 | +8.3% | 9.4% |
| Northampton | 10,570 | +2.0% | 3.3% |
| Wilson | 8,159 | −1.0% | 2.5% |
| Hellertown | 6,138 | +0.3% | 1.9% |
| Nazareth | 6,091 | +0.6% | 1.9% |
| Bangor | 5,118 | −0.5% | 1.6% |
| Wind Gap | 3,630 | +28.9% | 1.1% |
| Pen Argyl | 3,468 | −1.0% | 1.1% |
| North Catasauqua | 3,229 | +8.6% | 1.0% |
| Freemansburg | 3,003 | +4.6% | 0.9% |
| Bath | 2,903 | +2.1% | 0.9% |
- Walnutport
- Roseto
- Tatamy
- West Easton
- East Bangor
- Stockertown
- Portland
- Glendon
- Chapman
21 incorporated places, as listed in the U.S. Census Bureau’s 2020 place reference files. “(part)” marks a place that extends into another county. Residents: U.S. Census Bureau population estimates for July 1, 2025 (Vintage 2025). A place that extends beyond Northampton County is counted whole, so it has no share.
Northampton County, Homes
Homes in Northampton County
Of Northampton County's 128,612 homes, 59% are detached houses, against 57% across Pennsylvania; 11% are in buildings of five or more homes. Half of its homes were built before 1970, close to Pennsylvania's 1965: 42% date from before 1960 and 19% from 2000 or later. 71% of occupied homes are lived in by their owner (Pennsylvania: 69%); in the rest a tenant can run a test, but a fix is the landlord's to make.
| Homes | Northampton County | Pennsylvania |
|---|---|---|
| Housing units | 128,612 | 5,779,663 |
| Detached houses | 59% | 57% |
| In buildings of 5 or more | 11% | 13% |
| Mobile homes | 2% | 4% |
| Built before 1960 | 42% | 45% |
| Built since 2000 | 19% | 14% |
| Middle year built | 1970 | 1965 |
| Owner-occupied | 71% | 69% |
Census Bureau, American Community Survey, 2019 to 2023: estimates from a sample of homes, looser for a small place. Shares by Radon411.