Reviewed and updated September 10, 2026. This article provides general public-health and referral guidance, not testing, medical, legal or engineering advice.
The short answer
NYSDOH's town dataset contains many Elmira results at or above EPA's 4 pCi/L action level. That makes radon a practical local testing issue. It does not mean every Elmira home is elevated, and the townwide average should never be substituted for a test in the house you occupy or plan to buy.
The table below uses NYSDOH's public ‘Radon Test Results by Town: Beginning 1987’ dataset as retrieved September 10, 2026. These are accumulated program records, not a live 2026 survey, a random sample of all homes or a prediction model for a specific address.
| Test location | Homes tested | Average | Below 4 | 4 to under 20 | 20 or higher |
|---|---|---|---|---|---|
| Basement | 1,086 | 11.06 pCi/L | 337 | 571 | 178 |
| First floor | 234 | 5.77 pCi/L | 146 | 76 | 12 |
Counts and arithmetic averages are reproduced from the NYSDOH dataset. Participation, placement and time period limit what can be inferred.
Why basement and first-floor numbers should not be blended
NYSDOH separates short-term basement measurements from first-floor measurements because the locations answer different questions. Basement screening results tend to be higher; the state says basement concentrations average two to three times first-floor concentrations statewide. A basement result may be the right decision measure when that level is or could be occupied, but it should not be presented as the average exposure for every resident.
The Elmira records show that placement matters: the dataset has 1,086 basement records and 234 first-floor records, with different averages and distributions. Combining them would hide both the sample imbalance and the floor difference.
What the dataset does not establish
The records come from a program laboratory and extend back to 1987. People who choose to test are not necessarily representative of every household. Building stock changes, mitigation changes individual homes, and one unusually high result can pull an arithmetic average upward. The dataset's highest reading is real within the program, but it is not a likely outcome for the next house tested.
NYSDOH also publishes older model estimates that combine measurement information with geology for places with sparse samples. Those maps remain useful for planning and outreach, but the state labels them as estimates. Contemporary test data, historical program records and modeled prevalence are three different forms of evidence.
Local geology explains concern, not an address-level number
Radon originates in the decay of uranium in soil and rock and can move through foundation openings under pressure differences. The Chemung River valley, hillsides and neighborhoods built on different materials do not form a single uniform radon surface. Foundation construction and air movement inside the home add another layer of variation.
This is why EPA warns against using a radon-zone map to decide whether an individual home needs testing. The correct local conclusion is modest: Elmira has documented elevated results, so test the building correctly. Do not assign a result based on a block, school district or nearby house.
Turn the data into a household decision
If you have no current result, start with radon testing in Elmira. Choose the lowest level that could be occupied regularly and follow the device conditions. If a transaction is moving quickly, a certified testing professional can match the device and documentation to the deadline.
If the result is 4 pCi/L or higher, review the appropriate confirmation guidance and discuss reduction with a qualified mitigator. The Elmira mitigation guide explains the system, and the above-4 guide helps organize the immediate next steps.
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.