Long-term kit
RL116 long-term radon test kit
- Lab fee extra
Method: Alpha track
In home: 90 days to 12 months
Locations and reports
Radon Levels in Sullivan County, New York
EPA puts Sullivan County in Zone 1, its highest radon zone, and only 2 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
19.8%
4.7 pts below NY
- Sullivan
- 19.8%
- New York
- 24.5%
257 tests, 2008 to 2017
Median result
1.3pCi/L
Below action level
- Sullivan
- 1.3 pCi/L
- EPA
- 4.0 pCi/L
Midpoint of the tests, 2008 to 2017
Tests reported
257
51st of 61 by tests
- Sullivan
- 257
- 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
39 of 61
Middle half
- Sullivan
- 19.8%
- Chemung
- 52.3%
By share, of 61 with 30+ tests
Read a result for Sullivan County
Starts at Sullivan 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. Sullivan County's median reported result, 2008 to 2017.
The data
Sullivan County, At a glance
Sullivan County at a glance
Predicted: EPA radon zone
EPA Zone 1: highest predicted potential
EPA puts all of Sullivan 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 Sullivan County, 2023
| Year | Share of reported tests at or above 4 pCi/L |
|---|---|
| 2015 | 100.0% |
| 2016 | 50.0% |
| 2017 | 66.7% |
| 2019 | 0.0% |
| 2020 | 50.0% |
| 2023 | 0.0% |
2023: 0.0%. Across these years the share ran from 0.0% to 100.0%. Each column counts radon tests reported to CDC that year, not homes.
What these figures count
Only 2 tests were reported to CDC for Sullivan 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).
Sullivan County, Compared
Sullivan County radon figures, compared
Calculated by Radon411Sullivan County's 257 reported tests over the 2008 to 2017 laboratory totals had a middle value of 1.3 pCi/L and a maximum of 35.6 pCi/L, and 19.8% reached 4 pCi/L. New York as a whole (62 New York counties, pooled) comes to 24.5%: 4.7 points higher than here.
The newest figure, in 2023, counts only 2 tests (0.0% at or above 4 pCi/L), too few to compare, so this reading uses the 257-test figure.
Among its state's counties it ranks 39th 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, 164 tests (63.8%) came in under 2 pCi/L, against 51.7% statewide, and 42 tests (16.3%) fell between 2 and 4, against 23.7% statewide. The busiest year on file was 2017, with 12 tests reported; the quietest, 2019, had 1.
EPA's 1993 zone map puts Sullivan 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 27.6% in Delaware County to 40.3% in Pike County, PA.
CDC also counts 7 tests taken after mitigation in Sullivan County for the same period: tests in homes where a fix was already in.
Pooled shares: Radon411's sum of CDC's county counts for one period.
Sullivan County, State data
New York's own radon test data
MeasuredWhat New York's own agencies publish about radon tests in Sullivan 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 Sullivan 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
70.3%
Average result
4.2 pCi/L
Tests behind these figures
3.2 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.
Sullivan County, Geology
The ground under Sullivan County
PredictedMost of the ground under Sullivan County is one class on USGS's geologic map: 99.8% of its land is high radon potential, with 0.2% moderate. 97.0% 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 | 97.0% |
| Valley and Ridge | Marine shelf sequence with basal Cambrian sandstones and conglomerates, shales, and limestones. | High | 12 | 2.8% |
Names, descriptions and indexes: U.S. Geological Survey, Geologic Radon Potential Map (2025). Shares: Radon411, from the map cut to the boundary.
Sullivan County beside the ground around it
Sullivan County has more high-potential ground than New York as a whole: 99.8% of its land against 48.9%. Of the 5 counties that border it, 3 have more high-potential ground, Ulster County the most at 100%.
The map rates the ground, not the air in any home.
Local help
Sullivan County, Local resources
Radon testing and mitigation in Sullivan 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
Sullivan County, Questions
Questions about radon in Sullivan County
Are radon levels high in Sullivan County?
In 2023, 0.0% of the radon tests reported to CDC for Sullivan County, New York were at or above 4 pCi/L, and the median reported pre-mitigation result was 0.9 pCi/L. Of 61 New York counties with 30 or more tests for the same period, 38 reported a higher share; pooled, the state comes to 24.5%.
Which counties border Sullivan County?
Sullivan County borders 5 counties: Wayne County, PA, Pike County, PA, Ulster County, NY, Orange County, NY and Delaware County, NY.
Products
Sullivan County, Products
Testing a home in Sullivan County
In Sullivan County, 19.8% of 257 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 Sullivan 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
MonitorX-Sense
XR0B-SR battery digital radon monitor with an alarm
- C-NRPP 2024/25: Not included
- Battery
- Alarm
- Screen
Method: Alpha spectrometry
First reading: Within 24 hours
Short-term kit
RA400 short-term liquid scintillation radon test kit, lab fee included
- Lab fee included
Method: Liquid scintillation
In home: 48 to 96 hours
- See every kit and monitor Test kits and monitors
Test kits and monitors: 1 of 3
Sullivan County is in EPA Zone 1, the highest predicted radon potential. Best radon monitors for Zone 1 counties like Sullivan County
Explore
Sullivan County, Bordering counties
Counties bordering Sullivan County
Calculated by Radon411- Radon levels in Pike County, PAEPA zone 2
40.3%at or above 4 pCi/L
Median 3.0 pCi/L · 390 tests · 20.5 points above Sullivan County
- Radon levels in Wayne County, PAEPA zone 2
32.5%at or above 4 pCi/L
Median 2.8 pCi/L · 252 tests · 12.7 points above Sullivan County
- Radon levels in Orange County, NYEPA zone 1
30.6%at or above 4 pCi/L
Median 2.2 pCi/L · 2,790 tests · 10.8 points above Sullivan County
- Radon levels in Ulster County, NYEPA zone 1
29.8%at or above 4 pCi/L
Median 2.2 pCi/L · 3,594 tests · 10.0 points above Sullivan County
- Radon levels in Delaware County, NYEPA zone 1
27.6%at or above 4 pCi/L
Median 1.8 pCi/L · 1,001 tests · 7.8 points above Sullivan County
Sullivan County, Cities and towns
Cities and towns in Sullivan County
The Census Bureau estimates 80,586 residents in Sullivan County for July 1, 2025, 2,125 more than in 2020 (+2.7%). That works out to 83 people per square mile of land. No town dominates: Monticello, the largest, has 7,195 residents, 8.9% of the total. Together its 6 incorporated places hold 19.2% of those residents; the other 80.8% live outside any of them. Reported testing is thin here: 257 tests over 2008 to 2017, or 3.2 for every 1,000 residents (2025 estimate), where New York as a whole comes to 4.9.
From Monticello to Jeffersonville, CDC publishes no figure by town: each reads Sullivan County's.
| Place | Residents | Since 2020 | Share of residents |
|---|---|---|---|
| Monticello | 7,195 | −0.6% | 8.9% |
| Liberty | 5,097 | +1.6% | 6.3% |
| Wurtsboro | 1,081 | −0.9% | 1.3% |
| Bloomingburg | 978 | −1.5% | 1.2% |
| Woodridge | 736 | +3.7% | 0.9% |
| Jeffersonville | 389 | −0.5% | 0.5% |
6 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).
Sullivan County, Homes
Homes in Sullivan County
Of Sullivan County's 49,667 homes, 71% are detached houses, against 41% across New York; 9% are mobile homes. Much of Sullivan County is recent building: 18% of its homes have gone up since 2000 and the middle year built is 1972, against 1958 for New York. 69% 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 | Sullivan County | New York |
|---|---|---|
| Housing units | 49,667 | 8,539,536 |
| Detached houses | 71% | 41% |
| In buildings of 5 or more | 7% | 34% |
| Mobile homes | 9% | 2% |
| Built before 1960 | 39% | 53% |
| Built since 2000 | 18% | 12% |
| Middle year built | 1972 | 1958 |
| Owner-occupied | 69% | 54% |
Census Bureau, American Community Survey, 2019 to 2023: estimates from a sample of homes, looser for a small place. Shares by Radon411.