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
Locations and reports
Radon Levels in Lewis County, New York
EPA puts Lewis County in Zone 2, its middle radon zone, and only 3 radon tests from it are on file with CDC (2022). Homes with elevated levels occur in all three zones, so only a test measures yours.
Data checked By Radon411Methodology
Share at 4+ pCi/L
20.2%
4.3 pts below NY
- Lewis
- 20.2%
- New York
- 24.5%
109 tests, 2008 to 2017
Median result
1.4pCi/L
Below action level
- Lewis
- 1.4 pCi/L
- EPA
- 4.0 pCi/L
Midpoint of the tests, 2008 to 2017
Tests reported
109
59th of 61 by tests
- Lewis
- 109
- Erie
- 13,822
Reported to CDC before any fix, 2008 to 2017
EPA radon zone
Zone 2
Moderate potential
- 1
- Zone 2
- 3
1 highest, 3 lowest
EPA predicts 2 to 4 pCi/L indoors
Rank in New York
38 of 61
Middle half
- Lewis
- 20.2%
- Chemung
- 52.3%
By share, of 61 with 30+ tests
Read a result for Lewis County
Starts at Lewis 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. Lewis County's median reported result, 2008 to 2017.
The data
Lewis County, At a glance
Lewis County at a glance
Predicted: EPA radon zone
EPA Zone 2: moderate predicted potential
Lewis County is a
USGS geologic potential: Moderate across 60% of the county's area
Predicted: EPA Map of Radon Zones
Measured: tests reported to CDC
Radon tests reported for Lewis County, 2022
| Year | Share of reported tests at or above 4 pCi/L |
|---|---|
| 2014 | 0.0% |
| 2015 | 0.0% |
| 2016 | 66.7% |
| 2017 | 0.0% |
| 2018 | 25.0% |
| 2019 | 14.3% |
| 2020 | 66.7% |
| 2021 | 0.0% |
| 2022 | 0.0% |
2022: 0.0%. Across these years the share ran from 0.0% to 66.7%. Each column counts radon tests reported to CDC that year, not homes.
What these figures count
Only 3 tests were reported to CDC for Lewis County over 2022, 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: 2022. Measured data period: 2005 to 2022 (every CDC figure on file).
Lewis County, Compared
Lewis County radon figures, compared
Calculated by Radon411Lewis County's 109 reported tests over the 2008 to 2017 laboratory totals had a middle value of 1.4 pCi/L and a maximum of 15.0 pCi/L, and 20.2% reached 4 pCi/L. New York as a whole (62 New York counties, pooled) comes to 24.5%: 4.3 points higher than here.
The newest figure, in 2022, counts only 3 tests (0.0% at or above 4 pCi/L), too few to compare, so this reading uses the 109-test figure.
Among its state's counties it ranks 38th 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, 66 tests (60.6%) came in under 2 pCi/L, against 51.7% statewide, and 21 tests (19.3%) fell between 2 and 4, against 23.7% statewide. The busiest year on file was 2017, with 10 tests reported; the quietest, 2021, had 2.
EPA's 1993 zone map puts Lewis County in Zone 2, a predicted county average between 2 and 4 pCi/L. USGS geology rates 60% of the county's land moderate radon potential.
Next door, the shares run from 13.2% in St. Lawrence County to 41.5% in Herkimer County, with Jefferson County, Oswego County and St. Lawrence County below Lewis County.
Pooled shares: Radon411's sum of CDC's county counts for one period.
Lewis County, State data
New York's own radon test data
MeasuredWhat New York's own agencies publish about radon tests in Lewis 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 Lewis 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
19%
Average result
6.8 pCi/L
Tests behind these figures
4.2 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.
Lewis County, Geology
The ground under Lewis County
PredictedUSGS's geologic map splits Lewis County: 60.4% of its land is moderate radon potential and 39.6% low. The map puts 39.6% of Lewis County in the area it calls Adirondacks and 27.9% in Tug Hill Plateau, with 2 smaller areas beside them. USGS gives the first a radon index of 8, in the low band (5 to 8), and the second 9, in the moderate band (9 to 11).
| Area | The rock, in USGS's words | Potential | Radon index | Share of land |
|---|---|---|---|---|
| Adirondacks | Anorthosite and charnockitic gneisses. | Low | 8 | 39.6% |
| Tug Hill Plateau | Limestone, dolomite, chert. | Moderate | 9 | 27.9% |
| Erie-Ontario Lowland | Limestone, dolomite, shale, sandstone, and salt deposits. | Moderate | 9 | 17.7% |
| Northwest Lowlands | Glacial gravel deposits, marble, quartzite, felsic to mafic gneiss. | Moderate | 11 | 14.8% |
Names, descriptions and indexes: U.S. Geological Survey, Geologic Radon Potential Map (2025). Shares: Radon411, from the map cut to the boundary.
Lewis County beside the ground around it
Across New York 48.9% of the land is rated high; none of Lewis County's is. Of the 5 counties that border it, 2 have more high-potential ground, Oneida County the most at 9.7%.
The map rates the ground, not the air in any home.
Local help
Lewis County, Local resources
Radon testing and mitigation in Lewis 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
Lewis County, Questions
Questions about radon in Lewis County
Are radon levels high in Lewis County?
In 2022, 0.0% of the radon tests reported to CDC for Lewis County, New York were at or above 4 pCi/L, and the median reported pre-mitigation result was 1.0 pCi/L. Of 61 New York counties with 30 or more tests for the same period, 37 reported a higher share; pooled, the state comes to 24.5%.
Which counties border Lewis County?
Lewis County borders 5 counties: Jefferson County, Herkimer County, Oneida County, Oswego County and St. Lawrence County.
Products
Lewis County, Products
Testing a home in Lewis County
In Lewis County, 20.2% of 109 tests reported to CDC over the 2008 to 2017 laboratory totals reached 4 pCi/L, against 24.5% pooled across New York. In Zone 2 a short-term kit (2 to 90 days) is the quick first check in Lewis County; a long-term test tells the year-round average.
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-3786 rechargeable radon monitor with a 3.5-inch color screen
- C-NRPP 2024/25: Not included
- Battery
- Alarm
- Screen
Method: Ion chamber
First reading: Within 10 minutes
- See every kit and monitor Test kits and monitors
Test kits and monitors: 1 of 3
Explore
Lewis County, Bordering counties
Counties bordering Lewis County
Calculated by Radon411- Radon levels in Herkimer CountyEPA zone 3
41.5%at or above 4 pCi/L
Median 3.1 pCi/L · 337 tests · 21.3 points above Lewis County
- Radon levels in Oneida CountyEPA zone 2
34.6%at or above 4 pCi/L
Median 2.5 pCi/L · 2,051 tests · 14.4 points above Lewis County
- Radon levels in Jefferson CountyEPA zone 2
16.0%at or above 4 pCi/L
Median 1.5 pCi/L · 1,204 tests · 4.2 points below Lewis County
- Radon levels in Oswego CountyEPA zone 2
15.2%at or above 4 pCi/L
Median 1.4 pCi/L · 778 tests · 5.0 points below Lewis County
- Radon levels in St. Lawrence CountyEPA zone 2
13.2%at or above 4 pCi/L
Median 1.2 pCi/L · 151 tests · 7.0 points below Lewis County
Lewis County, Cities and towns
Cities and towns in Lewis County
Lewis County's population has barely moved since 2020: 26,479 residents on July 1, 2025 against 26,571 then, by the Census Bureau's estimates. That works out to 21 people per square mile of land. No town dominates: Lowville, the largest, has 3,309 residents, 12.5% of the total. Together its 8 incorporated places hold 25.1% of those residents; the other 74.9% live outside any of them. CDC's 109 reported tests for 2008 to 2017 work out to 4.1 per 1,000 residents (2025 estimate), close to New York's 4.9.
From Lowville to Turin, CDC publishes no figure by town: each reads Lewis County's.
| Place | Residents | Since 2020 | Share of residents |
|---|---|---|---|
| Lowville | 3,309 | −0.8% | 12.5% |
| Copenhagen | 659 | −0.6% | 2.5% |
| Croghan | 632 | −0.8% | 2.4% |
| Port Leyden | 588 | −0.3% | 2.2% |
| Lyons Falls | 587 | −0.5% | 2.2% |
| Castorland | 341 | +0.3% | 1.3% |
| Constableville | 303 | −0.7% | 1.1% |
| Turin | 214 | −0.5% | 0.8% |
8 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).
Lewis County, Homes
Homes in Lewis County
Lewis County is a place of houses on their own lots: 78% of its 15,572 homes are detached single-family houses, against 41% across New York. Much of Lewis County is recent building: 17% of its homes have gone up since 2000 and the middle year built is 1972, against 1958 for New York. Owners live in 80% of the occupied homes (New York: 54%), so for most households a test and a fix are their own to order.
| Homes | Lewis County | New York |
|---|---|---|
| Housing units | 15,572 | 8,539,536 |
| Detached houses | 78% | 41% |
| In buildings of 5 or more | 3% | 34% |
| Mobile homes | 11% | 2% |
| Built before 1960 | 42% | 53% |
| Built since 2000 | 17% | 12% |
| Middle year built | 1972 | 1958 |
| Owner-occupied | 80% | 54% |
Census Bureau, American Community Survey, 2019 to 2023: estimates from a sample of homes, looser for a small place. Shares by Radon411.