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 Hartford County, Connecticut
EPA puts Hartford County in Zone 3, its lowest radon zone, and 31.5% of its 606 reported radon tests (2019) 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
31.5%
3.6 pts below CT
- Hartford
- 31.5%
- CT
- 35.1%
606 tests, 2019
Median result
1.4pCi/L
Below action level
- Hartford
- 1.4 pCi/L
- EPA
- 4.0 pCi/L
Midpoint of the tests, 2019
Tests reported
606
3rd of 8 by tests
- Hartford
- 606
- Fairfield
- 2,784
Reported to CDC before any fix, 2019
EPA radon zone
Zone 3
Lower potential
- 1
- 2
- Zone 3
1 highest, 3 lowest
EPA predicts under 2 pCi/L indoors
Rank in CT
7 of 8
Lowest quarter
- Hartford
- 31.5%
- New London
- 48.5%
By share, of 8 with 30+ tests
Read a result for Hartford County
Starts at Hartford County's median, 1.4 pCi/L
EPA’s own thresholds; the figures are the area’s, never this home’s.
EPA’s reading of 1.4 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. Hartford County's median reported result, 2019.
The data
Hartford County, At a glance
Hartford County at a glance
Predicted: EPA radon zone
EPA Zone 3: lower predicted potential
USGS geologic potential: Low across 75% of the county's area
Predicted: EPA Map of Radon Zones
Measured: tests reported to CDC
Radon tests reported for Hartford County, 2019
| Year | Share of reported tests at or above 4 pCi/L |
|---|---|
| 2014 | 51.9% |
| 2015 | 64.3% |
| 2016 | 48.5% |
| 2017 | 38.0% |
| 2018 | 26.0% |
| 2019 | 31.5% |
2019: 31.5%. Across these years the share ran from 26.0% to 64.3%. Each column counts radon tests reported to CDC that year, not homes.
What these figures count
These are the 606 tests reported to CDC for Hartford County over 2019, 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: 2019. Measured data period: 2005 to 2019 (every CDC figure on file).
Hartford County, Compared
Hartford County radon figures, compared
Calculated by Radon411In Hartford County, about 3 in 10 reported tests in 2019 (191 of 606) were at or above EPA's action level. Against the national pool of 29.0%, the gap is 2.5 points higher. Across 8 Connecticut counties pooled together, 35.1% of tests reached that level, so Hartford County runs 3.6 points below its state.
Of 5 neighbours with a figure, 4 reported a larger share at or above 4 pCi/L and 1 a smaller one; the spread is 29.4% (Tolland County) to 48.5% (New London County). By share, Hartford County is 7th of 8 Connecticut counties with 30 or more tests for the same period.
Year by year, 2014 opened at 51.9% and 2019 closed at 31.5% (down 20.4 points), with 2015 the high at 64.3%. Half the tests came in under 1.4 pCi/L and half over it; the single highest reached 48.6 pCi/L. Below the action level, 347 tests (57.3%) came in under 2 pCi/L, against 47.9% statewide, and 68 tests (11.2%) fell between 2 and 4, against 17.0% statewide.
The reported tests do not follow EPA's Zone 3 label for Hartford County (predicted average under 2 pCi/L): 31.5% of them reached 4 pCi/L, more than a low-potential zone suggests. USGS geology rates 75% of the county's land low radon potential.
The busiest year on file was 2015, with 611 tests reported; the quietest, 2016, had 487.
Hartford CountyConnecticut, pooled
| Year | Tests | Hartford County, at or above 4 pCi/L | Connecticut, pooled |
|---|---|---|---|
| 2014 | 518 | 51.9% | 53.1% |
| 2015 | 611 | 64.3% | 63.4% |
| 2016 | 487 | 48.5% | 45.1% |
| 2017 | 569 | 38.0% | 38.3% |
| 2018 | 496 | 26.0% | 31.0% |
| 2019 | 606 | 31.5% | 35.1% |
Pooled shares: Radon411's sum of CDC's county counts for one period.
Hartford County, Geology
The ground under Hartford County
PredictedMost of the ground under Hartford County is one class on USGS's geologic map: 75.3% of its land is low radon potential, with 19.6% high and 5.0% moderate. The map puts 75.3% of Hartford County in the area it calls Newark Terrane (Mesozoic Basins) and 12.7% in Connecticut Valley Synclinorium, with 4 smaller areas beside them. USGS gives the first a radon index of 8, in the low band (5 to 8), and the second 12, in the high band (12 to 17).
| Area | The rock, in USGS's words | Potential | Radon index | Share of land |
|---|---|---|---|---|
| Newark Terrane (Mesozoic Basins) | Sedimentary and igneous rocks including dolerite, arkose, basalt. | Low | 8 | 75.3% |
| Connecticut Valley Synclinorium | Schist, gneiss and phyllite. | High | 12 | 12.7% |
| Bronson Hill Anticlinorium | Granite gneiss, schist, amphibolite. | High | 12 | 6.9% |
| Merrimack Synclinorium | Schist, gneiss, gabbro. | Moderate | 11 | 3.4% |
| Taconic Allochthons | Cambrian schist. | Moderate | 11 | 1.0% |
| Proterozoic massifs | Gneiss, granitic gneiss, amphibolite, mica schist. | Moderate | 10 | 0.6% |
Names, descriptions and indexes: U.S. Geological Survey, Geologic Radon Potential Map (2025). Shares: Radon411, from the map cut to the boundary.
Hartford County beside the ground around it
Connecticut as a whole has more high-potential ground than Hartford County: 44.1% of its land, against 19.6% here. Of the 6 counties that border it, 5 have more high-potential ground, New London County the most at 58.4%.
The map rates the ground, not the air in any home.
Local help
Hartford County, Local resources
Radon testing and mitigation in Hartford County
Listed radon businesses with an address in Hartford County:
- Radon ProgramRadon Program, run by Department of Public Health, does not license radon professionals and offers free or discounted test kits, and answers questions about testing and mitigation in Connecticut.Visit the program’s page(opens in a new tab)
- Free and low-cost kitsThe program says:
A part of the partnership includes providing LHDs free short-term radon in air test kits for distribution to community residents.
- Compare kits
- Professionals in Connecticut71 professionals are listed in Connecticut.
Listed radon professionals by town: Hartford
What Connecticut's program says
- Phone
- (860) 509-7300
- DPH.RadonReports@ct.gov
- Licensing of radon professionals
The State of Connecticut does not license or otherwise certify radon professionals, however, the Radon Program maintains lists of nationally certified professionals in accordance with the requirements of CGS § 19a-14b (5)(b).
What it means
Hartford County, Questions
Questions about radon in Hartford County
Are radon levels high in Hartford County?
In 2019, 31.5% of the radon tests reported to CDC for Hartford County, Connecticut were at or above 4 pCi/L, and the median reported pre-mitigation result was 1.4 pCi/L. Of 8 Connecticut counties with 30 or more tests for the same period, 6 reported a higher share; pooled, the state comes to 35.1%.
Which counties border Hartford County?
Hartford County borders 6 counties: Tolland County, CT, Middlesex County, CT, New Haven County, CT, Litchfield County, CT, Hampden County, MA and New London County, CT.
Products
Hartford County, Products
Testing a home in Hartford County
In Hartford County, 31.5% of 606 tests reported to CDC in 2019 reached 4 pCi/L, against 35.1% pooled across Connecticut. 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 Hartford County.
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
Hartford County, Bordering counties
Counties bordering Hartford County
Calculated by Radon411- Radon levels in New London County, CTEPA zone 1
48.5%at or above 4 pCi/L
Median 3.5 pCi/L · 396 tests · 17.0 points above Hartford County
- Radon levels in New Haven County, CTEPA zone 1
37.9%at or above 4 pCi/L
Median 2.2 pCi/L · 1,007 tests · 6.4 points above Hartford County
- Radon levels in Middlesex County, CTEPA zone 1
34.5%at or above 4 pCi/L
Median 2.0 pCi/L · 571 tests · 3.0 points above Hartford County
- Radon levels in Litchfield County, CTEPA zone 2
33.8%at or above 4 pCi/L
Median 2.0 pCi/L · 346 tests · 2.3 points above Hartford County
- Radon levels in Tolland County, CTEPA zone 2
29.4%at or above 4 pCi/L
Median 1.8 pCi/L · 221 tests · 2.1 points below Hartford County
- Radon levels in Hampden County, MAEPA zone 2
No CDC figure for 2019; its page reads it against its own neighbours.
Hartford County, Cities and towns
Cities and towns in Hartford County
Hartford is its largest town, with 121,981 residents.
From Hartford to Bristol, CDC publishes no figure by town: each reads Hartford County's.
| Place | Residents | Since 2020 | Share of residents |
|---|---|---|---|
| Hartford | 121,981 | +1.2% | Not published |
| New Britain | 76,286 | +4.6% | Not published |
| Bristol | 62,341 | +2.6% | Not published |
3 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).