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 Tompkins County, New York
EPA puts Tompkins County in Zone 1, its highest radon zone, and only 18 radon tests from it are on file with CDC (2023). Homes with elevated levels occur in all three zones, so only a test measures yours.
Data checked By Radon411Methodology
Share at 4+ pCi/L
28.0%
3.5 pts above NY
- Tompkins
- 28.0%
- New York
- 24.5%
3,372 tests, 2008 to 2017
Median result
2.3pCi/L
Below action level
- Tompkins
- 2.3 pCi/L
- EPA
- 4.0 pCi/L
Midpoint of the tests, 2008 to 2017
Tests reported
3,372
8th of 61 by tests
- Tompkins
- 3,372
- Erie
- 13,822
Reported to CDC before any fix, 2008 to 2017
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
25 of 61
Middle half
- Tompkins
- 28.0%
- Chemung
- 52.3%
By share, of 61 with 30+ tests
Read a result for Tompkins County
Starts at Tompkins County's median, 2.3 pCi/L
EPA’s own thresholds; the figures are the area’s, never this home’s.
EPA’s reading of 2.3 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. Tompkins County's median reported result, 2008 to 2017.
The data
Tompkins County, At a glance
Tompkins County at a glance
Predicted: EPA radon zone
EPA Zone 1: highest predicted potential
EPA puts all of Tompkins 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 Tompkins County, 2023
| Year | Share of reported tests at or above 4 pCi/L |
|---|---|
| 2014 | 40.3% |
| 2015 | 31.0% |
| 2016 | 26.0% |
| 2017 | 26.9% |
| 2018 | 29.3% |
| 2019 | 32.1% |
| 2020 | 19.8% |
| 2021 | 23.3% |
| 2022 | 47.8% |
| 2023 | 38.9% |
2023: 38.9%. Across these years the share ran from 19.8% to 47.8%. Each column counts radon tests reported to CDC that year, not homes.
What these figures count
Only 18 tests were reported to CDC for Tompkins County over 2023, and tests are often run on homes being sold or already suspected of a problem: so few describe neither the county nor this house.
Measured: CDC tracking data. Figure above: 2023. Measured data period: 2005 to 2023 (every CDC figure on file).
Tompkins County, Compared
Tompkins County radon figures, compared
Calculated by Radon411Tompkins County's 3,372 reported tests over the 2008 to 2017 laboratory totals had a middle value of 2.3 pCi/L and a maximum of 106.9 pCi/L, and 28.0% reached 4 pCi/L. New York as a whole (62 New York counties, pooled) comes to 24.5%: 3.5 points lower than here.
The newest figure, in 2023, counts only 18 tests (38.9% at or above 4 pCi/L), too few to compare, so this reading uses the 3,372-test figure.
Among its state's counties it ranks 25th of 61 New York counties with 30 or more tests for the same period. Statewide for the same period, Chemung County reported the highest share (52.3%) and Bronx County the lowest (3.2%).
Below the action level, 1,472 tests (43.7%) came in under 2 pCi/L, against 51.7% statewide, and 956 tests (28.4%) fell between 2 and 4, against 23.7% statewide. The busiest year on file was 2019, with 168 tests reported; the quietest, 2023, had 18.
EPA's 1993 zone map puts Tompkins County in Zone 1, a predicted county average above 4 pCi/L. USGS geology rates 100% of the county's land high radon potential.
Next door, the shares run from 21.3% in Seneca County to 52.3% in Chemung County, with Cayuga County and Seneca County below Tompkins County. Over 9 years of annual figures the share rose 7.5 points, from 40.3% in 2014 to 47.8% in 2022; its peak was 47.8% in 2022.
CDC also counts 233 tests taken after mitigation in Tompkins County for the same period: tests in homes where a fix was already in.
Tompkins CountyNew York, pooled
47.8% % of tests22.4% % of tests
| Year | Tests | Tompkins County, at or above 4 pCi/L | New York, pooled |
|---|---|---|---|
| 2014 | 144 | 40.3% | 16.6% |
| 2015 | 116 | 31.0% | 21.4% |
| 2016 | 104 | 26.0% | 20.4% |
| 2017 | 119 | 26.9% | 31.6% |
| 2018 | 123 | 29.3% | 26.9% |
| 2019 | 168 | 32.1% | 28.0% |
| 2020 | 86 | 19.8% | 22.7% |
| 2021 | 30 | 23.3% | 18.9% |
| 2022 | 69 | 47.8% | 22.4% |
Pooled shares: Radon411's sum of CDC's county counts for one period.
Tompkins County, State data
New York's own radon test data
MeasuredWhat New York's own agencies publish about radon tests in Tompkins 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 Tompkins 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
28.3%
Average result
4.1 pCi/L
Tests behind these figures
130.8 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.
Tompkins County, Geology
The ground under Tompkins County
PredictedUSGS's geologic map puts all of Tompkins 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.
Tompkins County beside the ground around it
Tompkins County has more high-potential ground than New York as a whole: 100% of its land against 48.9%. Of the 6 counties that border it, none has as large a share of high-potential ground; Chemung County comes nearest at 100%.
The map rates the ground, not the air in any home.
Local help
Tompkins County, Local resources
Radon testing and mitigation in Tompkins County
Listed radon businesses with an address in Tompkins 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: Ithaca
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
Tompkins County, Questions
Questions about radon in Tompkins County
Are radon levels high in Tompkins County?
In 2023, 38.9% of the radon tests reported to CDC for Tompkins County, New York were at or above 4 pCi/L, and the median reported pre-mitigation result was 3.3 pCi/L. Of 61 New York counties with 30 or more tests for the same period, 24 reported a higher share; pooled, the state comes to 24.5%.
Which counties border Tompkins County?
Tompkins County borders 6 counties: Tioga County, Schuyler County, Cortland County, Seneca County, Chemung County and Cayuga County.
Products
Tompkins County, Products
Testing a home in Tompkins County
In Tompkins County, 28.0% of 3,372 tests reported to CDC over the 2008 to 2017 laboratory totals reached 4 pCi/L, against 24.5% pooled across New York. In Zone 1 the year-round level in Tompkins 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
RadonPro Wi-Fi radon monitor with a built-in Geiger counter
- C-NRPP 2024/25: Not included
- Plug-in
- Wi-Fi
- Alarm
- Screen, app
First reading: Within 5 minutes
Short-term kitFirst Alert
RD1 short-term charcoal radon test kit
- Lab fee included
Method: Charcoal
In home: 2 to 4 days
- See every kit and monitor Test kits and monitors
Test kits and monitors: 1 of 3
Tompkins County is in EPA Zone 1, the highest predicted radon potential. Best radon monitors for Zone 1 counties like Tompkins County
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Tompkins County, Bordering counties
Counties bordering Tompkins County
Calculated by Radon411- Radon levels in Chemung CountyEPA zone 1
52.3%at or above 4 pCi/L
Median 4.3 pCi/L · 1,537 tests · 24.3 points above Tompkins County
- Radon levels in Cortland CountyEPA zone 1
51.0%at or above 4 pCi/L
Median 4.1 pCi/L · 788 tests · 23.0 points above Tompkins County
- Radon levels in Tioga CountyEPA zone 1
38.9%at or above 4 pCi/L
Median 2.7 pCi/L · 1,419 tests · 10.9 points above Tompkins County
- Radon levels in Schuyler CountyEPA zone 1
38.6%at or above 4 pCi/L
Median 2.5 pCi/L · 236 tests · 10.6 points above Tompkins County
- Radon levels in Cayuga CountyEPA zone 1
27.8%at or above 4 pCi/L
Median 2.1 pCi/L · 726 tests · 0.2 points below Tompkins County
- Radon levels in Seneca CountyEPA zone 1
21.3%at or above 4 pCi/L
Median 2.0 pCi/L · 319 tests · 6.7 points below Tompkins County
Tompkins County, Cities and towns
Cities and towns in Tompkins County
About 104,047 people live in Tompkins County by the Census Bureau's estimate for July 1, 2025, 1,461 fewer than in 2020 (−1.4%). That works out to 219 people per square mile of land. Its largest town, Ithaca, has 33,632 residents, 32.3% of the total. Together its 7 incorporated places hold 45.6% of those residents; the other 54.4% live outside any of them. Testing is reported here more often than across the state: CDC's 3,372 reported tests for 2008 to 2017 come to 32.4 for every 1,000 residents (2025 estimate), against 4.9 for New York.
From Ithaca to Freeville, CDC publishes no figure by town: each reads Tompkins County's.
| Place | Residents | Since 2020 | Share of residents |
|---|---|---|---|
| Ithaca | 33,632 | +4.8% | 32.3% |
| Cayuga Heights | 3,860 | −5.2% | 3.7% |
| Lansing | 3,814 | +2.4% | 3.7% |
| Groton | 2,077 | −5.5% | 2.0% |
| Dryden | 1,820 | −6.1% | 1.7% |
| Trumansburg | 1,755 | +0.2% | 1.7% |
| Freeville | 443 | −6.7% | 0.4% |
Places in Tompkins County with a city page: 1 of 1
7 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).
Tompkins County, Homes
Homes in Tompkins County
Fewer than six in ten of Tompkins County's 47,362 homes are detached houses (49%, against 41% across New York); the rest are attached, in shared buildings or mobile. Much of Tompkins County is recent building: 17% of its homes have gone up since 2000 and the middle year built is 1974, against 1958 for New York. 54% 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 | Tompkins County | New York |
|---|---|---|
| Housing units | 47,362 | 8,539,536 |
| Detached houses | 49% | 41% |
| In buildings of 5 or more | 24% | 34% |
| Mobile homes | 8% | 2% |
| Built before 1960 | 36% | 53% |
| Built since 2000 | 17% | 12% |
| Middle year built | 1974 | 1958 |
| Owner-occupied | 54% | 54% |
Census Bureau, American Community Survey, 2019 to 2023: estimates from a sample of homes, looser for a small place. Shares by Radon411.