Reviewed and updated September 10, 2026. This article provides general public-health and referral guidance, not testing, medical, legal or engineering advice.
Test the home, not the reputation of the neighborhood
NYSDOH's historical program records include elevated results in Horseheads, and Chemung County is on the state's high-radon-area list. Those facts support testing; they do not tell you whether one house near the village, along the valley or toward the surrounding hills is above 4 pCi/L.
Differences in soil connection, slab cracks, sumps, crawlspaces, foundation additions and building pressure can outweigh the distance between properties. The Horseheads data article separates useful local evidence from address-level guesswork.
Choose the test around the decision
A short-term test can support a screening or time-sensitive sale when its conditions are controlled. EPA's current buyer and seller guide requires a minimum of 48 hours and describes paired passive tests, sequential tests and continuous monitors as options in transactions. A long-term test lasting more than 90 days is better for estimating a year-round average when time permits.
If you are deciding whether to occupy or finish a basement, place the device on the lowest level that could be used regularly. Do not place it in a crawlspace, bathroom, kitchen, hallway or furnace room. The instructions supplied with the specific device remain controlling.
Professional testing is most valuable when documentation matters
A certified tester can select a device, document closed-house conditions, identify possible interference and deliver a report suited to a real-estate deadline. Continuous monitors can record changes during the measurement period, but the monitor still has to be placed and operated correctly.
A DIY kit can also answer a homeowner's question when used according to the instructions. NYSDOH maintains a testing program and a list of certified professionals. Homeowners who want local professional help can request a radon test through our referral form; the independent provider confirms availability and testing details.
Read 4 pCi/L as an action point
EPA recommends fixing at 4 pCi/L or higher and considering reduction between 2 and 4 pCi/L. A test result is an estimate of the concentration during that period, so confirmation depends on test type and context. Do not average unrelated measurements from different floors without professional guidance.
Keep the report, test location, dates and any notes about unusual weather or open windows. If the result supports action, the regional cost guide and basement-testing guide can help prepare for the next conversation.
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.