Reviewed and updated September 10, 2026. This article provides general public-health and referral guidance, not testing, medical, legal or engineering advice.
Big Flats has documented elevated results
NYSDOH's town dataset contains 155 Big Flats basement records and 40 first-floor records beginning in 1987. Of those, 119 basement results and 18 first-floor results were 4 pCi/L or higher. The records are enough to reject the idea that local radon is merely theoretical.
They are not enough to calculate the present-day prevalence for every home. The sample is voluntary program data, basement tests dominate, and 40 first-floor records are a modest base for townwide conclusions. A buyer or homeowner should use the data to justify testing, not to guess a result.
| Test location | Homes tested | Average | Below 4 | 4 to under 20 | 20 or higher |
|---|---|---|---|---|---|
| Basement | 155 | 19.09 pCi/L | 36 | 53 | 66 |
| First floor | 40 | 6.44 pCi/L | 22 | 15 | 3 |
Historical program records retrieved September 10, 2026. The state warns that its test data may not reflect all tests completed in New York.
Why a high average is not a typical-house promise
The basement arithmetic average is 19.09 pCi/L, and the highest recorded result is 118.3. High observations can pull an average upward, so it is important to read the distribution: 36 were below 4, 53 were from 4 to under 20, and 66 were 20 or higher.
This does not mean a randomly selected Big Flats basement will measure 19.09. It means the NYSDOH program has recorded a substantial number of elevated tests among participating homes. Individual results can be lower or higher, and mitigation changes a home's later measurements.
Valley geography does not replace building science
Big Flats spans a broad valley setting with surrounding higher ground, but a landscape description cannot resolve the soil pathways beneath one foundation. Slab condition, drainage, crawlspaces, utility penetrations and indoor pressure all affect how radon enters.
EPA's radon-zone guidance is explicit: zone maps were developed for broad planning and should be supplemented with state information, but they should not determine whether a particular home needs testing. Even homes in lower-potential areas should be tested.
How this compares with nearby records
Elmira and Horseheads have larger NYSDOH town samples, while Big Flats has fewer records and therefore less statistical stability. Southport also appears in the dataset, but Pine City does not have a separate row; it would be misleading to label the Southport numbers as Pine City measurements. County figures likewise should not be relabeled as town figures.
The honest regional story is that elevated results have been documented across multiple Chemung County municipalities. The practical household story remains one measurement at a time, placed on the appropriate level under controlled conditions.
What a Big Flats homeowner should do
Test the lowest level that could be used regularly. Use a certified professional when transaction documentation or a tight deadline calls for it; otherwise, a properly handled approved kit can be appropriate. The DIY and professional testing comparison explains the tradeoffs.
At 4 pCi/L or higher, follow confirmation guidance and speak with a qualified mitigator. Foundation transitions and sump systems common to many lower levels deserve a site-specific evaluation; see the sump and radon guide before making changes to drainage openings.
Sources
Primary guidance used for this article
We use government and public-health sources, distinguish historical datasets from current household measurements, and do not invent local results. Read our editorial policy.