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 Cortland County, New York
EPA puts Cortland County in Zone 1, its highest radon zone, and high results are common there: 54.9% of the 122 radon tests reported to CDC (2023) 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
54.9%
22.9 pts above NY
- Cortland
- 54.9%
- New York
- 32.0%
122 tests, 2023
Median result
4.6pCi/L
Action level reached
- Cortland
- 4.6 pCi/L
- EPA
- 4.0 pCi/L
Midpoint of the tests, 2023
Tests reported
122
3rd of 6 by tests
- Cortland
- 122
- 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
1 of 6
Top quarter
- Cortland
- 54.9%
- Cortland
- 54.9%
By share, of 6 with 30+ tests
Read a result for Cortland County
Starts at Cortland County's median, 4.6 pCi/L
EPA’s own thresholds; the figures are the area’s, never this home’s.
EPA’s reading of 4.6 pCi/L
At or above 4 pCi/L
- Under 20 to 1.9 pCi/L
- 2 to 4consider a fix
- 4 and aboveEPA says fix it
This result is at or above 4 pCi/L. EPA recommends fixing a home when the radon level is 4 pCi/L or higher. Cortland County's median reported result, 2023.
The data
Cortland County, At a glance
Cortland County at a glance
Predicted: EPA radon zone
EPA Zone 1: highest predicted potential
EPA puts all of Cortland 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 Cortland County, 2023
| Year | Share of reported tests at or above 4 pCi/L |
|---|---|
| 2014 | 59.8% |
| 2015 | 64.5% |
| 2016 | 57.7% |
| 2017 | 63.0% |
| 2018 | 67.2% |
| 2019 | 57.9% |
| 2020 | 64.0% |
| 2021 | 48.6% |
| 2022 | 55.0% |
| 2023 | 54.9% |
2023: 54.9%. Across these years the share ran from 48.6% to 67.2%. Each column counts radon tests reported to CDC that year, not homes.
What these figures count
These are the 122 tests reported to CDC for Cortland 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).
Cortland County, Compared
Cortland County radon figures, compared
Calculated by Radon411More than half: 54.9% of the 122 radon tests reported to CDC for Cortland County in 2023 read at least 4 pCi/L. That places it 1st of 6 New York counties with 30 or more tests for the same period. That is 22.9 points above the 32.0% pooled from 56 New York counties.
The median result, 4.6 pCi/L, sits above EPA's 4 pCi/L action level, and the top reported result was 224.5 pCi/L. The rest split 25.4% under 2 pCi/L and 19.7% from 2 to 4 (New York: 44.7% and 23.3%). Zone 1 on EPA's map (predicted average above 4 pCi/L) and a 54.9% share point the same way here.
Onondaga County, the one bordering county with a figure for the same period, reported 32.6%. Statewide for the same period, Genesee County reported the highest share (46.7%) and Monroe County the lowest (10.0%).
The busiest year on file was 2022, with 240 tests reported; the quietest, 2021, had 37.
Over 10 years of annual figures the share fell 4.9 points, from 59.8% in 2014 to 54.9% in 2023; its peak was 67.2% in 2018. Nationally, every county with a figure for the same period pools to 33.4%; Cortland County sits 21.5 points above it.
Cortland CountyNew York, pooled
54.9% % of tests32.0% % of tests
| Year | Tests | Cortland County, at or above 4 pCi/L | New York, pooled |
|---|---|---|---|
| 2014 | 92 | 59.8% | 16.6% |
| 2015 | 62 | 64.5% | 21.4% |
| 2016 | 71 | 57.7% | 20.4% |
| 2017 | 181 | 63.0% | 31.6% |
| 2018 | 128 | 67.2% | 26.9% |
| 2019 | 195 | 57.9% | 28.0% |
| 2020 | 136 | 64.0% | 22.7% |
| 2021 | 37 | 48.6% | 18.9% |
| 2022 | 240 | 55.0% | 22.4% |
| 2023 | 122 | 54.9% | 32.0% |
Pooled shares: Radon411's sum of CDC's county counts for one period.
Cortland County, State data
New York's own radon test data
MeasuredWhat New York's own agencies publish about radon tests in Cortland 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 Cortland 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
60.2%
Average result
9.6 pCi/L
Tests behind these figures
128.8 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.
Cortland County, Geology
The ground under Cortland County
PredictedUSGS's geologic map puts all of Cortland County's mapped land in one class: high radon potential. All of it lies in the area the map calls Allegheny Plateau, to which USGS gives a radon index of 12, in the high band (12 to 17).
| Area | The rock, in USGS's words | Potential | Radon index | Share of land |
|---|---|---|---|---|
| Allegheny Plateau | Shale, limestone, and sandstone. | High | 12 | 100% |
Names, descriptions and indexes: U.S. Geological Survey, Geologic Radon Potential Map (2025). Shares: Radon411, from the map cut to the boundary.
Cortland County beside the ground around it
Cortland County has more high-potential ground than New York as a whole: 100% of its land against 48.9%. Of the 7 counties that border it, none has as large a share of high-potential ground; Broome County comes nearest at 100%.
The map rates the ground, not the air in any home.
Local help
Cortland County, Local resources
Radon testing and mitigation in Cortland 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.
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
Cortland County, Questions
Questions about radon in Cortland County
Are radon levels high in Cortland County?
In 2023, 54.9% of the radon tests reported to CDC for Cortland County, New York were at or above 4 pCi/L, and the median reported pre-mitigation result was 4.6 pCi/L. Of 6 New York counties with 30 or more tests for the same period, none reported a higher share; pooled, the state comes to 32.0%.
Which counties border Cortland County?
Cortland County borders 7 counties: Tompkins County, Chenango County, Broome County, Tioga County, Madison County, Onondaga County and Cayuga County.
Products
Cortland County, Products
Testing a home in Cortland County
In Cortland County, 54.9% of 122 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 Cortland 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
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
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
- See every kit and monitor Test kits and monitors
Test kits and monitors: 1 of 3
Cortland County is in EPA Zone 1, the highest predicted radon potential. Best radon monitors for Zone 1 counties like Cortland County
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Cortland County, Bordering counties
Counties bordering Cortland County
Calculated by Radon411- Radon levels in Chenango CountyEPA zone 1
100.0%at or above 4 pCi/L
Median 21.3 pCi/L · 1 test · 45.1 points above Cortland County
- Radon levels in Madison CountyEPA zone 1
62.5%at or above 4 pCi/L
Median 6.2 pCi/L · 8 tests · 7.6 points above Cortland County
- Radon levels in Tioga CountyEPA zone 1
44.4%at or above 4 pCi/L
Median 2.0 pCi/L · 9 tests · 10.5 points below Cortland County
- Radon levels in Tompkins CountyEPA zone 1
38.9%at or above 4 pCi/L
Median 3.3 pCi/L · 18 tests · 16.0 points below Cortland County
- Radon levels in Onondaga CountyEPA zone 1
32.6%at or above 4 pCi/L
Median 2.5 pCi/L · 224 tests · 22.3 points below Cortland County
- Radon levels in Broome CountyEPA zone 1
25.0%at or above 4 pCi/L
Median 1.4 pCi/L · 12 tests · 29.9 points below Cortland County
- Radon levels in Cayuga CountyEPA zone 1
19.2%at or above 4 pCi/L
Median 1.9 pCi/L · 26 tests · 35.7 points below Cortland County
Cortland County, Cities and towns
Cities and towns in Cortland County
About 45,850 people live in Cortland County by the Census Bureau's estimate for July 1, 2025, 895 fewer than in 2020 (−1.9%). That works out to 92 people per square mile of land. Its largest town, Cortland, has 17,394 residents, 37.9% of the total. Together its 4 incorporated places hold 48.6% of those residents; the other 51.4% live outside any of them. Testing is reported here more often than across the state: CDC's 122 reported tests for 2023 come to 2.7 for every 1,000 residents (2025 estimate), against 0.1 for New York.
From Cortland to Marathon, CDC publishes no figure by town: each reads Cortland County's.
| Place | Residents | Since 2020 | Share of residents |
|---|---|---|---|
| Cortland | 17,394 | −0.6% | 37.9% |
| Homer | 3,054 | −4.1% | 6.7% |
| McGraw | 970 | −4.2% | 2.1% |
| Marathon | 874 | −4.3% | 1.9% |
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).
Cortland County, Homes
Homes in Cortland County
Of Cortland County's 20,842 homes, 64% are detached houses, against 41% across New York; 12% are in buildings of five or more homes. Half of its homes were built before 1961, close to New York's 1958: 49% date from before 1960 and 8% 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 | Cortland County | New York |
|---|---|---|
| Housing units | 20,842 | 8,539,536 |
| Detached houses | 64% | 41% |
| In buildings of 5 or more | 12% | 34% |
| Mobile homes | 7% | 2% |
| Built before 1960 | 49% | 53% |
| Built since 2000 | 8% | 12% |
| Middle year built | 1961 | 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.