Short-term kitKidde
442020 short-term charcoal radon test kit
- Lab fee included
Method: Charcoal
In home: 3 days
Locations and reports
Radon Levels in Franklin County, Massachusetts
EPA puts Franklin County in Zone 2, its middle radon zone, and 22.3% of its 802 reported radon tests (2008 to 2017, laboratory totals) were 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
22.3%
1.5 pts below MA
- Franklin
- 22.3%
- MA
- 23.8%
802 tests, 2008 to 2017
Median result
1.6pCi/L
Below action level
- Franklin
- 1.6 pCi/L
- EPA
- 4.0 pCi/L
Midpoint of the tests, 2008 to 2017
Tests reported
802
12th of 14 by tests
- Franklin
- 802
- Middlesex
- 75,220
Reported to CDC before any fix, 2008 to 2017
EPA radon zone
Zone 2
Moderate potential
- 1
- Zone 2
- 3
1 highest, 3 lowest
EPA predicts 2 to 4 pCi/L indoors
Rank in MA
5 of 14
Middle half
- Franklin
- 22.3%
- Worcester
- 33.5%
By share, of 14 with 30+ tests
Read a result for Franklin County
Starts at Franklin County's median, 1.6 pCi/L
EPA’s own thresholds; the figures are the area’s, never this home’s.
EPA’s reading of 1.6 pCi/L
Below 2 pCi/L
- Under 20 to 1.9 pCi/L
- 2 to 4consider a fix
- 4 and aboveEPA says fix it
This result is below 2 pCi/L, the level at which EPA says a fix should be considered. Franklin County's median reported result, 2008 to 2017.
The data
Franklin County, At a glance
Franklin County at a glance
Predicted: EPA radon zone
EPA Zone 2: moderate predicted potential
Franklin County is a
USGS geologic potential: Moderate across 85% of the county's area
Predicted: EPA Map of Radon Zones
Measured: tests reported to CDC
Radon tests reported for Franklin County, 2008 to 2017, laboratory
Under 2 pCi/L: 57%2 to 4 pCi/L: 21%4 pCi/L and above: 22%
Of 802 pre-mitigation tests reported to CDC, not homes in this area.
| Result band | Tests Measured | Share Measured |
|---|---|---|
| Under 2 pCi/L | 452 | 56.4% |
| 2 to 4 pCi/L | 171 | 21.3% |
| 4 pCi/L and above | 179 | 22.3% |
What these figures count
These are the 802 tests reported to CDC for Franklin County over 2008 to 2017 (laboratory totals), 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: 2008 to 2017, laboratory. Measured data period: 2005 to 2017 (every CDC figure on file).
Franklin County, Compared
Franklin County radon figures, compared
Calculated by Radon411Franklin County's 802 reported tests over the 2008 to 2017 laboratory totals had a middle value of 1.6 pCi/L and a maximum of 61.0 pCi/L, and 22.3% reached 4 pCi/L. Massachusetts as a whole (14 Massachusetts counties, pooled) comes to 23.8%: 1.5 points higher than here.
Among its state's counties it ranks 5th of 14 Massachusetts counties with 30 or more tests for the same period. Statewide for the same period, Worcester County reported the highest share (33.5%) and Nantucket County the lowest (5.0%).
Below the action level, 452 tests (56.4%) came in under 2 pCi/L, against 49.6% statewide, and 171 tests (21.3%) fell between 2 and 4, against 26.6% statewide. CDC's ten-year totals for Franklin County went from 755 tests (2005 to 2014) to 802 (2008 to 2017), the share going from 22.4% to 22.3%.
EPA's 1993 zone map puts Franklin County in Zone 2, a predicted county average between 2 and 4 pCi/L. USGS geology rates 85% of the county's land moderate radon potential.
Next door, the shares run from 18.4% in Windham County, VT to 33.5% in Worcester County, with Cheshire County, NH, Hampshire County and Windham County, VT below Franklin County.
CDC also counts 12 tests taken after mitigation in Franklin County for the same period: tests in homes where a fix was already in.
Pooled shares: Radon411's sum of CDC's county counts for one period.
Franklin County, Geology
The ground under Franklin County
PredictedMost of the ground under Franklin County is one class on USGS's geologic map: 85.5% of its land is moderate radon potential, with 14.5% low. The map puts 44.4% of Franklin County in the area it calls Western Connecticut Valley Belt and 41.0% in Gneissic Domes, with one smaller area beside them. USGS gives the first a radon index of 11 and the second 10, both in the moderate band (9 to 11).
| Area | The rock, in USGS's words | Potential | Radon index | Share of land |
|---|---|---|---|---|
| Western Connecticut Valley Belt | Metasedimentary and metavolcanic gneiss and schist. | Moderate | 11 | 44.4% |
| Gneissic Domes | Domes of mafic gneiss surrounded by younger schists and amphobilites, intruded by granite, and overlain by sandy and gravelly to clayey glacial till. | Moderate | 10 | 41.0% |
| Mesozoic Basins | Sedimentary and igneous rocks inclusing dolerite, arkose, basalt. | Low | 8 | 14.5% |
Names, descriptions and indexes: U.S. Geological Survey, Geologic Radon Potential Map (2025). Shares: Radon411, from the map cut to the boundary.
Franklin County beside the ground around it
Across Massachusetts 31.9% of the land is rated high; none of Franklin County's is. Of the 6 counties that border it, 3 have more high-potential ground, Worcester County the most at 85.4%.
The map rates the ground, not the air in any home.
Local help
Franklin County, Local resources
Radon testing and mitigation in Franklin County
- Radon UnitRadon Unit, run by Department of Public Health, answers questions about testing, mitigation and the rules in Massachusetts.Visit the program’s page(opens in a new tab)
- Free and low-cost kitsAsk the program whether it has free or discounted kits, or compare kits you can buy.
- Compare kits
- Professionals in Massachusetts5 professionals are listed in Massachusetts.
What Massachusetts's program says
- Phone
- (800) 723-6695
- DPHIAQ.radon@mass.gov
What it means
Franklin County, Questions
Questions about radon in Franklin County
Are radon levels high in Franklin County?
Over the 2008 to 2017 laboratory totals, 22.3% of the radon tests reported to CDC for Franklin County, Massachusetts were at or above 4 pCi/L, and the median reported pre-mitigation result was 1.6 pCi/L. Of 14 Massachusetts counties with 30 or more tests for the same period, 4 reported a higher share; pooled, the state comes to 23.8%.
Which counties border Franklin County?
Franklin County borders 6 counties: Hampshire County, MA, Berkshire County, MA, Cheshire County, NH, Worcester County, MA, Windham County, VT and Bennington County, VT.
Products
Franklin County, Products
Testing a home in Franklin County
In Franklin County, 22.3% of 802 tests reported to CDC over the 2008 to 2017 laboratory totals reached 4 pCi/L, against 23.8% pooled across Massachusetts. In Zone 2 a short-term kit (2 to 90 days) is the quick first check in Franklin County; a long-term test tells the year-round average.
Test kits and monitors3
See every kit and monitor
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
MonitorAEGTEST
HOUND-1085 palm-sized rechargeable radon detector
- C-NRPP 2024/25: Not included
- Battery
- Alarm
- Screen
Method: Semiconductor sensor
First reading: Within 6 hours
- See every kit and monitor Test kits and monitors
Test kits and monitors: 1 of 3
Explore
Franklin County, Bordering counties
Counties bordering Franklin County
Calculated by Radon411- Radon levels in Worcester County, MAEPA zone 1
33.5%at or above 4 pCi/L
Median 2.6 pCi/L · 46,440 tests · 11.2 points above Franklin County
- Radon levels in Berkshire County, MAEPA zone 2
27.1%at or above 4 pCi/L
Median 1.7 pCi/L · 1,097 tests · 4.8 points above Franklin County
- Radon levels in Bennington County, VTEPA zone 2
25.8%at or above 4 pCi/L
Median 2.0 pCi/L · 733 tests · 3.5 points above Franklin County
- Radon levels in Cheshire County, NHEPA zone 2
20.4%at or above 4 pCi/L
Median 1.8 pCi/L · 952 tests · 1.9 points below Franklin County
- Radon levels in Hampshire County, MAEPA zone 2
18.8%at or above 4 pCi/L
Median 1.5 pCi/L · 2,457 tests · 3.5 points below Franklin County
- Radon levels in Windham County, VTEPA zone 2
18.4%at or above 4 pCi/L
Median 1.7 pCi/L · 1,127 tests · 3.9 points below Franklin County
Franklin County, Cities and towns
Cities and towns in Franklin County
Franklin County's population has barely moved since 2020: 70,698 residents on July 1, 2025 against 70,938 then, by the Census Bureau's estimates. That works out to 101 people per square mile of land. Greenfield, its one incorporated place, has 17,691 residents, 25.0% of the total. Reported testing is thin here: 802 tests over 2008 to 2017, or 11.3 for every 1,000 residents (2025 estimate), where Massachusetts as a whole comes to 32.7.
Greenfield is the one incorporated place here; CDC publishes no figure by town, so it reads Franklin County's.
| Place | Residents | Since 2020 | Share of residents |
|---|---|---|---|
| Greenfield | 17,691 | −0.1% | 25.0% |
One incorporated place, as listed in the U.S. Census Bureau’s 2020 place reference files. Residents: U.S. Census Bureau population estimates for July 1, 2025 (Vintage 2025).
Franklin County, Homes
Homes in Franklin County
Of Franklin County's 34,424 homes, 65% are detached houses, against 51% across Massachusetts; 12% are in buildings of five or more homes. Half of its homes were built before 1961, close to Massachusetts' 1963: 49% date from before 1960 and 10% from 2000 or later. 69% of occupied homes are lived in by their owner (Massachusetts: 63%); in the rest a tenant can run a test, but a fix is the landlord's to make.
| Homes | Franklin County | Massachusetts |
|---|---|---|
| Housing units | 34,424 | 3,014,657 |
| Detached houses | 65% | 51% |
| In buildings of 5 or more | 12% | 22% |
| Mobile homes | 2% | 1% |
| Built before 1960 | 49% | 47% |
| Built since 2000 | 10% | 14% |
| Middle year built | 1961 | 1963 |
| Owner-occupied | 69% | 63% |
Census Bureau, American Community Survey, 2019 to 2023: estimates from a sample of homes, looser for a small place. Shares by Radon411.