Radon levels in St. Lawrence County, New York

LowEPA Zone 2

Predicted long-term basement average of 1.5 pCi/L (model estimate) across 36 ZIP codes - about 18% below the US average of 1.8, close to the New York average of 1.4. Ranked #47 of 62 New York counties.

Test St. Lawrence County, NY once anyway - radon varies house to house

The predicted basement average here is 1.5 pCi/L, below the EPA's 2 pCi/L "consider fixing" threshold. That's good news for the area - but the EPA still recommends every home be tested, because foundation cracks, soil pockets and ventilation make one house very different from its neighbor. One inexpensive kit settles it.

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Predicted (model estimate). The pCi/L figures on this page are long-term area averages from a peer-reviewed national model built on millions of real radon tests (2001-2021). They describe the typical home in this area - not your home, which can be several times higher or lower. The EPA radon zone is a separate, 1993 county-level classification. How the numbers work.

1.5 ± 0.07

pCi/L predicted basement mean (model SD)

0.9 ± 0.07

pCi/L predicted upstairs (above-ground) mean

1.3-1.8

range of ZIP-level basement predictions in the county

What this means for St. Lawrence

The typical St. Lawrence County home is predicted below 2 pCi/L, the lowest band. That is the best case an area can show - but it describes the average house, and the ZIP-level predictions within the county still span 1.3 to 1.8 pCi/L.

Note that the EPA classifies St. Lawrence County as Zone 2 while the newer model predicts 1.5 pCi/L. The zone map predates two decades of test data; where they disagree, we grade on the model but show both. County figures weight each ZIP by its 2010 Census population, so they describe where people live rather than empty land.

Comparable New York counties: Clinton County (1.5), Schenectady County (1.5), Warren County (1.5), Jefferson County (1.5). The state's highest is Schuyler County at 2.8 pCi/L.

ZIP codes in St. Lawrence County

Predicted basement and upstairs means by ZIP (model estimate). ZIPs whose land is mostly in this county.

ZIPBasementUpstairsGrade
136761.5 ± 0.060.8Low
136621.4 ± 0.060.8Low
136691.4 ± 0.060.8Low
136171.3 ± 0.181.1Low
136421.5 ± 0.060.9Low
136681.7 ± 0.050.9Low
136671.5 ± 0.060.8Low
136131.6 ± 0.050.9Low
136541.5 ± 0.060.9Low
136581.6 ± 0.061.0Low
136971.6 ± 0.050.8Low
136461.6 ± 0.061.0Low
136601.6 ± 0.060.9Low
136251.8 ± 0.060.9Low
136521.6 ± 0.050.9Low
136301.7 ± 0.060.9Low
136941.6 ± 0.061.0Low
136801.6 ± 0.060.9Low
129671.7 ± 0.050.8Low
136841.7 ± 0.060.9Low
136351.7 ± 0.060.8Low
136811.6 ± 0.061.0Low
136901.7 ± 0.070.8Low
136211.4 ± 0.070.9Low
136721.6 ± 0.060.7Low
129651.8 ± 0.061.0Low
136871.8 ± 0.060.9Low
136701.7 ± 0.070.8Low
136641.6 ± 0.060.9Low
136141.5 ± 0.060.9Low
136331.6 ± 0.060.9Low
136661.6 ± 0.060.8Low
136391.5 ± 0.060.8Low
129731.4 ± 0.070.7Low
136951.7 ± 0.060.8Low
129221.5 ± 0.080.7Low

If your test comes back at 4 pCi/L or higher

Mitigation is a routine job: a fan-driven pipe that vents soil gas from under the slab to above the roofline, typically $800-$2,500 installed (typical range; local quotes vary). Use certified professionals: EPA find-a-professional. Read the full mitigation guide.

St. Lawrence County radon questions

Is radon high in St. Lawrence County, New York?
Low. The model predicts a long-term basement average of 1.5 pCi/L in St. Lawrence County (about 18% below the US average of 1.8 and close to the New York average of 1.4). That is below the EPA's 2 pCi/L "consider fixing" threshold, though individual homes still vary. Ranked 47 of 62 New York counties.
Should I test for radon in St. Lawrence County?
Yes, once. The EPA recommends testing every home regardless of area, and the model's ZIP-level predictions in St. Lawrence County already range from 1.3 to 1.8 pCi/L. A short-term kit costs little and settles the question for your house.
What does EPA Radon Zone 2 mean for St. Lawrence County?
Zone 2 - moderate potential (2-4 pCi/L). The zone map dates from 1993 and classifies whole counties. The newer model's predicted average of 1.5 pCi/L does not line up with Zone 2, which is common - the EPA itself says high-radon homes exist in every zone. Neither replaces a test of your own home.
How much does radon mitigation cost in St. Lawrence County?
A standard active sub-slab depressurization system typically runs $800-$2,500 installed nationally; New York quotes vary with foundation type (slab, crawlspace, basement), home size and local labor. Get two or three bids from certified mitigators listed by your state radon program or the EPA's find-a-professional page.

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