Short-term kit
Radon Short Term Test Kit short-term charcoal radon test kit, lab fee included
- Lab fee included
Method: Charcoal
In home: 2 to 7 days
Locations and reports
Radon Levels in Suffolk County, Massachusetts
EPA puts Suffolk County in Zone 3, its lowest radon zone, and most reported tests there come back low, though 10.4% of 8,525 (2008 to 2017, laboratory totals) reached 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
10.4%
13.4 pts below MA
- Suffolk
- 10.4%
- MA
- 23.8%
8,525 tests, 2008 to 2017
Median result
1.3pCi/L
Below action level
- Suffolk
- 1.3 pCi/L
- EPA
- 4.0 pCi/L
Midpoint of the tests, 2008 to 2017
Tests reported
8,525
7th of 14 by tests
- Suffolk
- 8,525
- Middlesex
- 75,220
Reported to CDC before any fix, 2008 to 2017
EPA radon zone
Zone 3
Lower potential
- 1
- 2
- Zone 3
1 highest, 3 lowest
EPA predicts under 2 pCi/L indoors
Rank in MA
13 of 14
Lowest quarter
- Suffolk
- 10.4%
- Worcester
- 33.5%
By share, of 14 with 30+ tests
Read a result for Suffolk County
Starts at Suffolk County's median, 1.3 pCi/L
EPA’s own thresholds; the figures are the area’s, never this home’s.
EPA’s reading of 1.3 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. Suffolk County's median reported result, 2008 to 2017.
The data
Suffolk County, At a glance
Suffolk County at a glance
Predicted: EPA radon zone
EPA Zone 3: lower predicted potential
USGS geologic potential: Low across 87% of the county's area
Predicted: EPA Map of Radon Zones
Measured: tests reported to CDC
Radon tests reported for Suffolk County, 2008 to 2017, laboratory
Under 2 pCi/L: 69%2 to 4 pCi/L: 21%4 pCi/L and above: 10%
Of 8,525 pre-mitigation tests reported to CDC, not homes in this area.
| Result band | Tests Measured | Share Measured |
|---|---|---|
| Under 2 pCi/L | 5,890 | 69.1% |
| 2 to 4 pCi/L | 1,752 | 20.6% |
| 4 pCi/L and above | 883 | 10.4% |
What these figures count
These are the 8,525 tests reported to CDC for Suffolk 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).
Suffolk County, Compared
Suffolk County radon figures, compared
Calculated by Radon411Suffolk County reports fewer high tests than Massachusetts overall. 10.4% of its 8,525 tests over the 2008 to 2017 laboratory totals were at or above 4 pCi/L. That is 13.4 points below the 23.8% pooled from 14 Massachusetts counties.
Ordered from highest share down, it comes 13th of 14 Massachusetts counties with 30 or more tests for the same period. Nationally, every county with a figure for the same period pools to 35.7%; Suffolk County sits 25.3 points below it.
Next door, the shares run from 21.2% in Norfolk County to 28.7% in Essex County. Zone 3 on EPA's map (predicted average under 2 pCi/L) and a 10.4% share point the same way here.
Half the tests came in under 1.3 pCi/L and half over it; the single highest reached 52.0 pCi/L. The rest split 69.1% under 2 pCi/L and 20.6% from 2 to 4 (Massachusetts: 49.6% and 26.6%).
CDC's ten-year totals for Suffolk County went from 9,184 tests (2005 to 2014) to 8,525 (2008 to 2017), the share going from 9.6% to 10.4%.
Pooled shares: Radon411's sum of CDC's county counts for one period.
Suffolk County, Geology
The ground under Suffolk County
PredictedMost of the ground under Suffolk County is one class on USGS's geologic map: 87.0% of its land is low radon potential, with 0.5% high and 4.2% moderate. The map puts 87.0% of Suffolk County in the area it calls Boston Basin and 4.2% in Esmond-Dedham terrane, with one smaller area beside them. USGS gives the first a radon index of 8, in the low band (5 to 8), and the second 11, in the moderate band (9 to 11).
| Area | The rock, in USGS's words | Potential | Radon index | Share of land |
|---|---|---|---|---|
| Boston Basin | Proterozoic to Pennsylvanian sedimentary rocks. | Low | 8 | 87.0% |
| Esmond-Dedham terrane | Granite plutons, mafic metasedimentary and metavolcanic rocks. | Moderate | 11 | 4.2% |
| Cape Ann and Peabody plutons | Felsic granitic rocks and lesser exposures of mafic plutonic rocks. | High | 13 | 0.5% |
Names, descriptions and indexes: U.S. Geological Survey, Geologic Radon Potential Map (2025). Shares: Radon411, from the map cut to the boundary.
Suffolk County beside the ground around it
Massachusetts as a whole has more high-potential ground than Suffolk County: 31.9% of its land, against 0.5% here. Every one of the 3 counties that border it has more high-potential ground, Essex County the most at 86.7%.
The map rates the ground, not the air in any home.
Local help
Suffolk County, Local resources
Radon testing and mitigation in Suffolk 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
Suffolk County, Questions
Questions about radon in Suffolk County
Are radon levels high in Suffolk County?
Over the 2008 to 2017 laboratory totals, 10.4% of the radon tests reported to CDC for Suffolk County, Massachusetts were at or above 4 pCi/L, and the median reported pre-mitigation result was 1.3 pCi/L. Of 14 Massachusetts counties with 30 or more tests for the same period, 12 reported a higher share; pooled, the state comes to 23.8%.
Which counties border Suffolk County?
Suffolk County borders 3 counties: Norfolk County, Middlesex County and Essex County.
Products
Suffolk County, Products
Testing a home in Suffolk County
In Suffolk County, 10.4% of 8,525 tests reported to CDC over the 2008 to 2017 laboratory totals reached 4 pCi/L, against 23.8% pooled across Massachusetts. Zone 3 is the lowest label, yet homes at or above 4 pCi/L occur in every zone: a short-term kit (2 to 90 days) is the quick first check in Suffolk County.
Test kits and monitors3
See every kit and monitor
Long-term kit
RL116 long-term radon test kit
- Lab fee extra
Method: Alpha track
In home: 90 days to 12 months
MonitorINKBIRD
INK-RD3 battery radon monitor with an e-ink screen
- C-NRPP 2024/25: Not included
- Battery
- Screen
First reading: Within 24 hours
- See every kit and monitor Test kits and monitors
Test kits and monitors: 1 of 3
Explore
Suffolk County, Bordering counties
Counties bordering Suffolk County
Calculated by Radon411- Radon levels in Essex CountyEPA zone 1
28.7%at or above 4 pCi/L
Median 2.2 pCi/L · 20,398 tests · 18.3 points above Suffolk County
- Radon levels in Middlesex CountyEPA zone 1
22.0%at or above 4 pCi/L
Median 1.9 pCi/L · 75,220 tests · 11.6 points above Suffolk County
- Radon levels in Norfolk CountyEPA zone 2
21.2%at or above 4 pCi/L
Median 1.8 pCi/L · 39,205 tests · 10.8 points above Suffolk County
Suffolk County, Cities and towns
Cities and towns in Suffolk County
Suffolk County's population has barely moved since 2020: 791,891 residents on July 1, 2025 against 791,372 then, by the Census Bureau's estimates. Packed into its land, that is 13,594 people per square mile. Boston alone is home to 672,973 of them, 85.0% of the total. Its 4 incorporated places account for all of those residents. Reported testing is thin here: 8,525 tests over 2008 to 2017, or 10.8 for every 1,000 residents (2025 estimate), where Massachusetts as a whole comes to 32.7.
From Boston to Winthrop Town, CDC publishes no figure by town: each reads Suffolk County's.
| Place | Residents | Since 2020 | Share of residents |
|---|---|---|---|
| Boston | 672,973 | +0.5% | 85.0% |
| Revere | 60,141 | −2.9% | 7.6% |
| Chelsea | 40,130 | −1.0% | 5.1% |
| Winthrop Town | 18,647 | −3.2% | 2.4% |
Places in Suffolk County with a city page: 1 of 1
4 incorporated places, 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).
Suffolk County, Homes
Homes in Suffolk County
Suffolk County has 353,930 homes, and many share a building: 44% are in buildings of five or more, 14% are detached houses, against 51% across Massachusetts. The homes are older than Massachusetts' as a whole: half were built before 1948 (1963 for Massachusetts), and 58% date from before 1960. Most occupied homes here are rented: owners live in 37% (Massachusetts: 63%). A tenant can run a test; a fix is the landlord's to make.
| Homes | Suffolk County | Massachusetts |
|---|---|---|
| Housing units | 353,930 | 3,014,657 |
| Detached houses | 14% | 51% |
| In buildings of 5 or more | 44% | 22% |
| Mobile homes | under 1% | 1% |
| Built before 1960 | 58% | 47% |
| Built since 2000 | 16% | 14% |
| Middle year built | 1948 | 1963 |
| Owner-occupied | 37% | 63% |
Census Bureau, American Community Survey, 2019 to 2023: estimates from a sample of homes, looser for a small place. Shares by Radon411.