Reviewed and updated September 10, 2026. This article provides general public-health and referral guidance, not testing, medical, legal or engineering advice.
What the state records show
NYSDOH's public town dataset, which accumulates program results beginning in 1987, contains 541 Horseheads basement records and 117 first-floor records. In those records, 402 basement tests and 58 first-floor tests were 4 pCi/L or higher. The distributions support testing as a real local concern.
They do not establish the current percentage of all Horseheads homes above the action level. The households were not selected as a random survey, the test periods span decades, and basement tests outnumber first-floor tests. Treat the figures as documented program experience, not a forecast.
| Test location | Homes tested | Average | Below 4 | 4 to under 20 | 20 or higher |
|---|---|---|---|---|---|
| Basement | 541 | 13.06 pCi/L | 139 | 290 | 112 |
| First floor | 117 | 8.85 pCi/L | 59 | 50 | 8 |
Dataset retrieved September 10, 2026. These historical program records may not represent all tests or all homes.
Why the first-floor average needs care
The dataset reports an arithmetic average of 8.85 pCi/L for the first-floor records, but it also reports a highest result of 224.9 pCi/L. A rare high value can pull an arithmetic mean upward. The distribution counts—59 below 4, 50 from 4 to under 20, and 8 at or above 20—give necessary context.
This is also why it would be misleading to tell a homeowner that 8.85 pCi/L is ‘the Horseheads level.’ It is the mean within a defined NYSDOH program subset. A correctly conducted measurement is needed for the home in question.
Horseheads and the surrounding county are not interchangeable
The state table assigns records by reported town, village or city. It does not publish a separate row for every hamlet or neighborhood, and a county average blends communities, floors and building conditions. Geographic context is useful for outreach, but local labels should not be stretched beyond the dataset.
NYSDOH identifies Chemung County as a high-radon-area county. That designation describes potential and supports broad testing. EPA expressly says zone maps should not decide whether an individual home needs testing.
Use the evidence in the right order
First, use regional and town evidence to justify taking the issue seriously. Second, conduct a test on the lowest level that could be used regularly, following the device conditions. Third, interpret the actual report and use confirmation guidance when needed.
A result at or above 4 pCi/L leads to a mitigation discussion, not panic. Start with testing guidance for Horseheads, then review what to do above 4 pCi/L and the regional mitigation-cost guide.
What a better future local dataset would include
For stronger current prevalence estimates, researchers would want recent tests selected or weighted to represent the housing stock, consistent floor placement, clear device and duration information, and enough observations to describe uncertainty. Results from mitigated and unmitigated homes would also need careful treatment. The public town table is valuable, but it was not designed to answer every one of those questions.
That limitation is not a reason to dismiss the records. It is a reason to make the claim match the evidence: elevated radon has been measured in Horseheads homes, floor placement changes the dataset, and every household needs its own valid test before making a property decision.
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.