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Radon Levels in Rensselaer County, New York

EPA puts Rensselaer County in Zone 1, its highest radon zone, and only 19 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

How to test this homeFind a certified tester

  • Share at 4+ pCi/L

    29.5%

    5.0 pts above NY

    Rensselaer
    29.5%
    New York
    24.5%

    1,577 tests, 2008 to 2017

  • Median result

    2.1pCi/L

    Below action level

    Rensselaer
    2.1 pCi/L
    EPA
    4.0 pCi/L

    Midpoint of the tests, 2008 to 2017

  • Tests reported

    1,577

    17th of 61 by tests

    Rensselaer
    1,577
    Erie
    13,822

    Reported to CDC before any fix, 2008 to 2017

  • EPA radon zone

    Zone 1

    Highest potential

    1. Zone 1
    2. 2
    3. 3

    1 highest, 3 lowest

    EPA predicts over 4 pCi/L indoors

  • Rank in New York

    23 of 61

    Middle half

    Rensselaer
    29.5%
    Chemung
    52.3%

    By share, of 61 with 30+ tests

Read a result for Rensselaer County

Starts at Rensselaer County's median, 2.1 pCi/L

2.1pCi/L

EPA’s own thresholds; the figures are the area’s, never this home’s.

EPA’s reading of 2.1 pCi/L

Between 2 and 4 pCi/L

  1. Under 20 to 1.9 pCi/L
  2. 2 to 4consider a fix
  3. 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. Rensselaer County's median reported result, 2008 to 2017.

Interpret this readingWhat a fix costs

The data

Rensselaer County, At a glance

Rensselaer County at a glance

Predicted: EPA radon zone

EPA Zone 1: highest predicted potential

EPA puts all of Rensselaer County in and predicts an average indoor of greater than 4 pCi/L (greater than 150 Bq/m³) across the county. That is one forecast for the whole county, not a reading of any address in it; homes above EPA's turn up in all three zones.

USGS geologic potential: High across 97% of the county's area

Predicted: EPA Map of Radon Zones

Measured: tests reported to CDC

Radon tests reported for Rensselaer County, 2023

Share of reported tests at or above 4 pCi/L, by year, Rensselaer County
Share of reported tests at or above 4 pCi/L, by year, Rensselaer County
YearShare of reported tests at or above 4 pCi/L
201420.7%
201540.0%
201640.5%
201748.7%
201826.2%
201924.2%
202016.5%
20217.2%
202250.0%
202326.3%

2023: 26.3%. Across these years the share ran from 7.2% to 50.0%. Each column counts radon tests reported to CDC that year, not homes.

What these figures count

Only 19 tests were reported to CDC for Rensselaer 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).

How to read these figures

Rensselaer County, Compared

Rensselaer County radon figures, compared

Calculated by Radon411

Rensselaer County's 1,577 reported tests over the 2008 to 2017 laboratory totals had a middle value of 2.1 pCi/L and a maximum of 100.2 pCi/L, and 29.5% reached 4 pCi/L. New York as a whole (62 New York counties, pooled) comes to 24.5%: 5.0 points lower than here.

The newest figure, in 2023, counts only 19 tests (26.3% at or above 4 pCi/L), too few to compare, so this reading uses the 1,577-test figure.

Among its state's counties it ranks 23rd 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, 745 tests (47.2%) came in under 2 pCi/L, against 51.7% statewide, and 366 tests (23.2%) fell between 2 and 4, against 23.7% statewide. The busiest year on file was 2014, with 357 tests reported; the quietest, 2022, had 12.

EPA's 1993 zone map puts Rensselaer County in Zone 1, a predicted county average above 4 pCi/L. USGS geology rates 97% of the county's land high radon potential.

Next door, the shares run from 15.7% in Albany County to 39.8% in Columbia County, with Greene County, Berkshire County, MA and Bennington County, VT below Rensselaer County. Over 8 years of annual figures the share fell 13.5 points, from 20.7% in 2014 to 7.2% in 2021; its peak was 48.7% in 2017.

CDC also counts 43 tests taken after mitigation in Rensselaer County for the same period: tests in homes where a fix was already in.

Share of reported tests at or above 4 pCi/L by year, Rensselaer County against New York2014 to 2021, years with 30 or more tests: Rensselaer County 20.7% to 7.2%, the state's pooled share 18.9% in 2021.
Rensselaer CountyNew York, pooled
Share of reported tests at or above 4 pCi/L by year, Rensselaer County against New York: data table
YearTestsRensselaer County, at or above 4 pCi/LNew York, pooled
201435720.7%16.6%
20157040.0%21.4%
201612140.5%20.4%
201711748.7%31.6%
201814926.2%26.9%
201920724.2%28.0%
202017016.5%22.7%
2021697.2%18.9%
Rensselaer County against New York, the United States and nearby counties, 2008 to 2017, laboratory
AreaTestsAt or above 4 pCi/LMedianDifference from Rensselaer County
Rensselaer County1,57729.5%2.1 pCi/LThis county
New York, pooled62 counties, pooled97,14524.5%Not pooled−5.0 points
United States, pooled2,661 counties, pooled2,013,54435.7%Not pooled+6.2 points
Chemung Countyhighest in the state1,53752.3%4.3 pCi/L+22.8 points
Bronx Countylowest in the state1853.2%0.5 pCi/L−26.3 points
Columbia County, NYborders it57339.8%2.7 pCi/L+10.3 points
Greene County, NYborders it52527.6%2.0 pCi/L−1.9 points
Berkshire County, MAborders it1,09727.1%1.7 pCi/L−2.4 points
Bennington County, VTborders it73325.8%2.0 pCi/L−3.7 points
Washington County, NYborders it1,59325.6%2.0 pCi/L−3.9 points
Saratoga County, NYborders it4,44922.3%2.0 pCi/L−7.2 points
Albany County, NYborders it2,74015.7%1.4 pCi/L−13.8 points
Where Rensselaer County's reported results fell, 2008 to 2017, laboratory, beside New York and the United States
ResultRensselaer County testsRensselaer County shareNew York shareU.S. shareAgainst New York
Under 2 pCi/L74547.2%51.7%39.6%−4.5 points
2 to 4 pCi/L36623.2%23.7%24.7%−0.5 points
4 pCi/L and above46629.5%24.5%35.7%+5.0 points
Rensselaer County ranked among the 61 New York counties with 30 or more tests, by share at or above 4 pCi/L, 2008 to 2017, laboratory
CountyRankTestsAt or above 4 pCi/LMedian
Oneida County18 of 612,05134.6%2.5 pCi/L
Chenango County19 of 6196133.4%2.6 pCi/L
Ontario County20 of 611,44832.8%2.6 pCi/L
Orange County21 of 612,79030.6%2.2 pCi/L
Ulster County22 of 613,59429.8%2.2 pCi/L
Rensselaer County23 of 611,57729.5%2.1 pCi/L
Onondaga County24 of 619,11428.4%2.0 pCi/L
Tompkins County25 of 613,37228.0%2.3 pCi/L
Cayuga County26 of 6172627.8%2.1 pCi/L
Greene County27 of 6152527.6%2.0 pCi/L
Delaware County28 of 611,00127.6%1.8 pCi/L
Rensselaer County radon tests by year, against New York's pooled share
YearTestsAt or above 4 pCi/LMedianHighestNew York, pooledChange from the row before
20231926.3%1.9 pCi/L26.7 pCi/L32.0%−23.7 points
20221250.0%2.9 pCi/L6.0 pCi/L22.4%+42.8 points
2021697.2%0.5 pCi/L27.9 pCi/L18.9%−9.3 points
202017016.5%0.7 pCi/L38.0 pCi/L22.7%−7.7 points
201920724.2%1.8 pCi/L52.0 pCi/L28.0%−2.0 points
201814926.2%2.0 pCi/L24.4 pCi/L26.9%−22.5 points
201711748.7%3.6 pCi/L41.9 pCi/L31.6%+8.2 points
201612140.5%2.8 pCi/L56.7 pCi/L20.4%+0.5 points
20157040.0%2.6 pCi/L36.4 pCi/L21.4%+19.3 points
201435720.7%0.9 pCi/L102.8 pCi/L16.6%First on file

Pooled shares: Radon411's sum of CDC's county counts for one period.

Rensselaer County, State data

New York's own radon test data

Measured

What New York's own agencies publish about radon tests in Rensselaer 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 Rensselaer 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

36.9%

Average result

5.2 pCi/L

Tests behind these figures

116.4 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.

Rensselaer County, Geology

The ground under Rensselaer County

Predicted

Most of the ground under Rensselaer County is one class on USGS's geologic map: 96.8% of its land is high radon potential, with 3.2% moderate. 96.8% of it lies in the area the map calls New England-Taconic Mountains, to which USGS gives a radon index of 12, in the high band (12 to 17).

USGS's geologic areas under Rensselaer County
AreaThe rock, in USGS's wordsPotentialRadon indexShare of land
New England-Taconic MountainsSlate, phyllite, graywacke, and limestone.High1296.8%
Hudson-Mohawk LowlandSandstone, siltstone, shale, and conglomerates.Moderate112.9%

Names, descriptions and indexes: U.S. Geological Survey, Geologic Radon Potential Map (2025). Shares: Radon411, from the map cut to the boundary.

Rensselaer County beside the ground around it

Rensselaer County has more high-potential ground than New York as a whole: 96.8% of its land against 48.9%. Of the 7 counties that border it, 2 have more high-potential ground, Greene County the most at 100%.

Share of land by USGS radon potential: Rensselaer County, the 7 counties bordering it and New York
AreaEPA zoneLow potentialModerate potentialHigh potential
Rensselaer CountyZone 1None3.2%96.8%
Berkshire County, MAZone 2None100%None
Albany CountyZone 1None42.8%57.2%
Bennington County, VTZone 2None100%None
Saratoga CountyZone 233.5%66.3%0.2%
Columbia CountyZone 1None0.6%99.4%
Greene CountyZone 1NoneNone100%
Washington CountyZone 120.9%25.4%53.7%
New York62 counties, pooled by land areaVaries22.0%28.2%48.9%

The map rates the ground, not the air in any home.

Local help

Rensselaer County, Local resources

Radon testing and mitigation in Rensselaer County

What New York's program says
Phone
518-402-7556
Email
radon@health.ny.gov
Licensing of radon professionals
NYS does not certify or license radon testers.

What it means

Rensselaer County, Questions

Questions about radon in Rensselaer County

Are radon levels high in Rensselaer County?

In 2023, 26.3% of the radon tests reported to CDC for Rensselaer County, New York were at or above 4 pCi/L, and the median reported pre-mitigation result was 1.9 pCi/L. Of 61 New York counties with 30 or more tests for the same period, 22 reported a higher share; pooled, the state comes to 24.5%.

Which counties border Rensselaer County?

Rensselaer County borders 7 counties: Berkshire County, MA, Albany County, NY, Bennington County, VT, Saratoga County, NY, Columbia County, NY, Greene County, NY and Washington County, NY.

Products

Rensselaer County, Products

Testing a home in Rensselaer County

In Rensselaer County, 29.5% of 1,577 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 Rensselaer 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

Rensselaer County is in EPA Zone 1, the highest predicted radon potential. Best radon monitors for Zone 1 counties like Rensselaer County

Explore

Rensselaer County, Bordering counties

Counties bordering Rensselaer County

Calculated by Radon411

Rensselaer County, Cities and towns

Cities and towns in Rensselaer County

Rensselaer County's population has barely moved since 2020: 160,510 residents on July 1, 2025 against 160,889 then, by the Census Bureau's estimates. That works out to 246 people per square mile of land. Its largest town, Troy, has 50,912 residents, 31.7% of the total. Together its 8 incorporated places hold 42.1% of those residents; the other 57.9% live outside any of them. Testing is reported here more often than across the state: CDC's 1,577 reported tests for 2008 to 2017 come to 9.8 for every 1,000 residents (2025 estimate), against 4.9 for New York.

From Troy to Valley Falls, CDC publishes no figure by town: each reads Rensselaer County's.

The cities and towns in Rensselaer County by residents, July 1, 2025
PlaceResidentsSince 2020Share of residents
Troy50,912−0.5%31.7%
Rensselaer9,421+2.3%5.9%
Hoosick Falls3,171−1.0%2.0%
Castleton-on-Hudson1,463−0.5%0.9%
Nassau1,077−1.9%0.7%
Schaghticoke547−2.0%0.3%
East Nassau512−1.9%0.3%
Valley Falls449−2.0%0.3%

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).

Rensselaer County, Homes

Homes in Rensselaer County

Of Rensselaer County's 74,388 homes, 56% are detached houses, against 41% across New York; 16% are in buildings of five or more homes. Half of its homes were built before 1962, close to New York's 1958: 48% date from before 1960 and 15% from 2000 or later. 64% 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 in Rensselaer County, New York, 2019 to 2023
HomesRensselaer CountyNew York
Housing units74,3888,539,536
Detached houses56%41%
In buildings of 5 or more16%34%
Mobile homes3%2%
Built before 196048%53%
Built since 200015%12%
Middle year built19621958
Owner-occupied64%54%

Census Bureau, American Community Survey, 2019 to 2023: estimates from a sample of homes, looser for a small place. Shares by Radon411.