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 Onondaga County, New York
EPA puts Onondaga County in Zone 1, its highest radon zone, and 32.6% of its 224 reported radon tests (2023) 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
32.6%
0.6 pts above NY
- Onondaga
- 32.6%
- New York
- 32.0%
224 tests, 2023
Median result
2.5pCi/L
Below action level
- Onondaga
- 2.5 pCi/L
- EPA
- 4.0 pCi/L
Midpoint of the tests, 2023
Tests reported
224
Most tested in New York
- Onondaga
- 224
Reported to CDC before any fix, 2023
EPA radon zone
Zone 1
Highest potential
- Zone 1
- 2
- 3
1 highest, 3 lowest
EPA predicts over 4 pCi/L indoors
Rank in New York
3 of 6
Middle half
- Onondaga
- 32.6%
- Cortland
- 54.9%
By share, of 6 with 30+ tests
Read a result for Onondaga County
Starts at Onondaga County's median, 2.5 pCi/L
EPA’s own thresholds; the figures are the area’s, never this home’s.
EPA’s reading of 2.5 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. Onondaga County's median reported result, 2023.
The data
Onondaga County, At a glance
Onondaga County at a glance
Predicted: EPA radon zone
EPA Zone 1: highest predicted potential
EPA puts all of Onondaga County in
USGS geologic potential: High across 54% of the county's area
Predicted: EPA Map of Radon Zones
Measured: tests reported to CDC
Radon tests reported for Onondaga County, 2023
| Year | Share of reported tests at or above 4 pCi/L |
|---|---|
| 2014 | 34.8% |
| 2015 | 42.3% |
| 2016 | 39.6% |
| 2017 | 45.1% |
| 2018 | 42.5% |
| 2019 | 43.9% |
| 2020 | 27.2% |
| 2021 | 25.0% |
| 2022 | 26.3% |
| 2023 | 32.6% |
2023: 32.6%. Across these years the share ran from 25.0% to 45.1%. Each column counts radon tests reported to CDC that year, not homes.
What these figures count
These are the 224 tests reported to CDC for Onondaga County over 2023, 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: 2023. Measured data period: 2005 to 2023 (every CDC figure on file).
Onondaga County, Compared
Onondaga County radon figures, compared
Calculated by Radon411In Onondaga County, about 3 in 10 reported tests in 2023 (73 of 224) were at or above EPA's action level. Against the national pool of 33.4%, the gap is 0.8 points lower. Across 56 New York counties pooled together, 32.0% of tests reached that level, so Onondaga County runs 0.6 points above its state.
Cortland County, the one bordering county with a figure for the same period, reported 54.9%. By share, Onondaga County is 3rd of 6 New York counties with 30 or more tests for the same period.
Year by year, 2014 opened at 34.8% and 2023 closed at 32.6% (down 2.2 points), with 2017 the high at 45.1%. Half the tests came in under 2.5 pCi/L and half over it; the single highest reached 236.3 pCi/L. Below the action level, 86 tests (38.4%) came in under 2 pCi/L, against 44.7% statewide, and 65 tests (29.0%) fell between 2 and 4, against 23.3% statewide.
Zone 1 on EPA's map (predicted average above 4 pCi/L) and a 32.6% share point the same way here. USGS geology rates 54% of the county's land high radon potential.
The busiest year on file was 2017, with 359 tests reported; the quietest, 2021, had 20.
Onondaga CountyNew York, pooled
| Year | Tests | Onondaga County, at or above 4 pCi/L | New York, pooled |
|---|---|---|---|
| 2014 | 256 | 34.8% | 16.6% |
| 2015 | 239 | 42.3% | 21.4% |
| 2016 | 227 | 39.6% | 20.4% |
| 2017 | 359 | 45.1% | 31.6% |
| 2018 | 127 | 42.5% | 26.9% |
| 2019 | 255 | 43.9% | 28.0% |
| 2020 | 206 | 27.2% | 22.7% |
| 2022 | 57 | 26.3% | 22.4% |
| 2023 | 224 | 32.6% | 32.0% |
Pooled shares: Radon411's sum of CDC's county counts for one period.
Onondaga County, State data
New York's own radon test data
MeasuredWhat New York's own agencies publish about radon tests in Onondaga County, with their period. These are not CDC's figures and are never added to them.
MeasuredState figures, not CDC's
What the New York State Department of Health reports for Onondaga County
Indoor air radon testing data (Environmental Public Health Tracker): short-term charcoal canister tests requested through the NYSDOH Radon Program, presented as five-year rolling averages. Period: 2015-2019. The publisher also lists 15 earlier periods.
Share at or above 4 pCi/L
41.4%
Average result
6.1 pCi/L
Tests behind these figures
245.2 tests a year on average
- Every figure is a five-year rolling average: the average result is the rolling average of each year's mean, and the test count is an average per year.
- The data only include tests requested through the NYSDOH Radon Program, and therefore may not capture all radon tests performed in a county.
- The data include both screening tests and post-mitigation tests, as it is not always possible to tell them apart.
- Radon testing by homeowners is optional in New York, so the values may not be representative of every home in the county.
- These figures describe tests reported to the New York State Department of Health in this area. They count a different set of tests than CDC's figures and are not a reading of any one home.
Measured: New York State Department of Health data, 2015-2019.
Onondaga County, Geology
The ground under Onondaga County
PredictedUSGS's geologic map splits Onondaga County: 54.4% of its land is high radon potential and 45.6% moderate. The map puts 54.4% of Onondaga County in the area it calls Allegheny Plateau and 45.6% in Erie-Ontario Lowland. USGS gives the first a radon index of 12, in the high band (12 to 17), and the second 9, in the moderate band (9 to 11).
| Area | The rock, in USGS's words | Potential | Radon index | Share of land |
|---|---|---|---|---|
| Allegheny Plateau | Shale, limestone, and sandstone. | High | 12 | 54.4% |
| Erie-Ontario Lowland | Limestone, dolomite, shale, sandstone, and salt deposits. | Moderate | 9 | 45.6% |
Names, descriptions and indexes: U.S. Geological Survey, Geologic Radon Potential Map (2025). Shares: Radon411, from the map cut to the boundary.
Onondaga County beside the ground around it
On high-potential ground Onondaga County is close to New York as a whole: 54.4% of its land against 48.9%. Of the 4 counties that border it, 3 have more high-potential ground, Cortland County the most at 100%.
The map rates the ground, not the air in any home.
Local help
Onondaga County, Local resources
Radon testing and mitigation in Onondaga County
Listed radon businesses with an address in Onondaga County:
- Radon ProgramRadon Program, run by New York State Department of Health, does not license radon professionals and offers free or discounted test kits, and answers questions about testing and mitigation in New York.Visit the program’s page(opens in a new tab)
- Free and low-cost kitsThe program says:
Providing patients with information about how low-cost test kits may be obtained from the Radon Program.
- Compare kits
- Professionals in New York88 professionals are listed in New York.
Listed radon professionals by town: Syracuse, East Syracuse, Camillus, Tully
What New York's program says
- Phone
- 518-402-7556
- radon@health.ny.gov
- Licensing of radon professionals
NYS does not certify or license radon testers.
What it means
Onondaga County, Questions
Questions about radon in Onondaga County
Are radon levels high in Onondaga County?
In 2023, 32.6% of the radon tests reported to CDC for Onondaga County, New York were at or above 4 pCi/L, and the median reported pre-mitigation result was 2.5 pCi/L. Of 6 New York counties with 30 or more tests for the same period, 2 reported a higher share; pooled, the state comes to 32.0%.
Which counties border Onondaga County?
Onondaga County borders 4 counties: Cayuga County, Madison County, Oswego County and Cortland County.
Products
Onondaga County, Products
Testing a home in Onondaga County
In Onondaga County, 32.6% of 224 tests reported to CDC in 2023 reached 4 pCi/L, against 32.0% pooled across New York. In Zone 1 the year-round level in Onondaga 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
Corentium Home 2 battery digital radon monitor
- C-NRPP 2024/25: Not included
- Battery
- Bluetooth
- Screen, app
Method: Alpha spectrometry
Readings: Every 60 minutes
Short-term kit
Air Chek Short-Term radon test kit you hang, lab fee included
- Lab fee included
In home: 72 to 168 hours
- See every kit and monitor Test kits and monitors
Test kits and monitors: 1 of 3
Onondaga County is in EPA Zone 1, the highest predicted radon potential. Best radon monitors for Zone 1 counties like Onondaga County
Explore
Onondaga County, Bordering counties
Counties bordering Onondaga County
Calculated by Radon411- Radon levels in Madison CountyEPA zone 1
62.5%at or above 4 pCi/L
Median 6.2 pCi/L · 8 tests · 29.9 points above Onondaga County
- Radon levels in Cortland CountyEPA zone 1
54.9%at or above 4 pCi/L
Median 4.6 pCi/L · 122 tests · 22.3 points above Onondaga County
- Radon levels in Cayuga CountyEPA zone 1
19.2%at or above 4 pCi/L
Median 1.9 pCi/L · 26 tests · 13.4 points below Onondaga County
- Radon levels in Oswego CountyEPA zone 2
0.0%at or above 4 pCi/L
Median 2.0 pCi/L · 1 test · 32.6 points below Onondaga County
Onondaga County, Cities and towns
Cities and towns in Onondaga County
About 466,584 people live in Onondaga County by the Census Bureau's estimate for July 1, 2025, 8,845 fewer than in 2020 (−1.9%). That works out to 599 people per square mile of land. Its largest town, Syracuse, has 144,896 residents, 31.1% of the total. Together its 16 incorporated places hold 41.2% of those residents; the other 58.8% live outside any of them. Testing is reported here more often than across the state: CDC's 224 reported tests for 2023 come to 0.5 for every 1,000 residents (2025 estimate), against 0.1 for New York.
From Syracuse to Fabius, CDC publishes no figure by town: each reads Onondaga County's.
| Place | Residents | Since 2020 | Share of residents |
|---|---|---|---|
| Syracuse | 144,896 | −2.2% | 31.1% |
| Baldwinsville | 7,582 | −2.8% | 1.6% |
| North Syracuse | 6,773 | +0.9% | 1.5% |
| Solvay | 6,427 | −3.0% | 1.4% |
| Manlius | 4,583 | −2.6% | 1.0% |
| Fayetteville | 4,126 | −2.9% | 0.9% |
| Minoa | 3,624 | −1.7% | 0.8% |
| East Syracuse | 2,973 | −3.3% | 0.6% |
| Skaneateles | 2,503 | −1.6% | 0.5% |
| Liverpool | 2,231 | −2.9% | 0.5% |
| Marcellus | 1,761 | −1.8% | 0.4% |
| Camillus | 1,258 | +2.8% | 0.3% |
Places in Onondaga County with a city page: 1 of 1
- Jordan
- Elbridge
- Tully
- Fabius
16 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).
Onondaga County, Homes
Homes in Onondaga County
Of Onondaga County's 211,683 homes, 63% are detached houses, against 41% across New York; 18% are in buildings of five or more homes. Half of its homes were built before 1963, close to New York's 1958: 46% date from before 1960 and 11% from 2000 or later. 66% of occupied homes are lived in by their owner (New York: 54%); in the rest a tenant can run a test, but a fix is the landlord's to make.
| Homes | Onondaga County | New York |
|---|---|---|
| Housing units | 211,683 | 8,539,536 |
| Detached houses | 63% | 41% |
| In buildings of 5 or more | 18% | 34% |
| Mobile homes | 1% | 2% |
| Built before 1960 | 46% | 53% |
| Built since 2000 | 11% | 12% |
| Middle year built | 1963 | 1958 |
| Owner-occupied | 66% | 54% |
Census Bureau, American Community Survey, 2019 to 2023: estimates from a sample of homes, looser for a small place. Shares by Radon411.