In Windham, NH, Signing the Radon Disclosure Isn't the Same as Testing for It

At the purchase and sale signing table, somewhere between the financing contingency and the inspection deadline, there is a single sheet of paper that gets signed almost on autopilot. It tells the buyer that radon, arsenic, and a handful of other things might be present in a New Hampshire home. The buyer initials it, the seller initials it, and everyone moves on to the parts of the contract that feel more consequential.

Here is what that piece of paper does not do: it does not confirm anyone tested for anything. New Hampshire law only requires a warning that these contaminants can occur in the state. It does not require a test, and it does not require the result of one if a test was never run. For a Windham buyer, that distinction matters more than the paperwork suggests, because Windham sits on the exact geology that makes radon and arsenic more than theoretical.

A Signature Isn't a Test Result

The notification form comes from New Hampshire RSA 477:4-a, and its language is worth reading closely because most buyers never do. The statute requires sellers to disclose that "radon, the product of decay of radioactive materials in rock, may be found in some areas of New Hampshire," alongside similar boilerplate on arsenic, lead paint, PFAS, and flood risk. That's the entire legal obligation on that particular form: a warning, not a result.

The actual substance lives in a separate statute, RSA 477:4-c, which requires sellers of one-to-four-family homes to disclose specifics about the private water supply, including the type of system, its location, and the date of the most recent water test, if one exists. If a Windham seller has never tested the well, that disclosure can legally say so. Nothing about that is unusual or improper. It just means the buyer's own due diligence period is doing real work, not confirming someone else's.

The House's Age Has Nothing to Do With It

Most buyers assume newer construction sidesteps these issues and older colonials carry the risk. Windham's geology does not sort itself that way. Rockingham County falls in the EPA's Radon Zone 2, and Windham sits over granite bedrock, the same rock that gives New Hampshire its nickname and its radon problem in the same breath. The New Hampshire Department of Health and Human Services tracks radon statewide and found that potential exposure across the state runs roughly four times the national estimate, with southeastern and eastern New Hampshire, including Rockingham County, among the areas where more than half of tested homes come back elevated.

What actually breaks the "newer is safer" assumption is how tightly modern homes are built. A home inspector quoted in New Hampshire Bulletin's 2023 reporting on the issue, Michael Talotta of Northern Vista Home Inspection and Radon Mitigation, said flatly that "the majority of the houses I test up here are elevated." He also noted that today's tighter building envelopes can act almost like a vacuum, pulling soil gas up through the foundation rather than letting it dissipate. A brand-new build in one of Windham's active subdivisions is not automatically safer on this specific measure than a decades-old colonial down the street. Bedrock does not check the deed.

What Testing and Fixing Actually Cost

The dollar figures are small relative to what they protect against, and that is the part worth sitting with before assuming a positive result changes anything about whether to move forward.

Set those numbers against Windham's own market. Through mid-2026, single-family sale prices in town have been running somewhere between roughly $725,000 and $785,000 depending on the data source and the exact window measured. A combined radon and water test panel, run together, lands under $400. Against a home price in that range, it is a rounding error, not a budget line that should make anyone hesitate to order it.

Arsenic Is the Quieter Problem

Radon gets more attention because it's tied directly to lung cancer risk and has a memorable nickname problem in the Granite State. Arsenic is the one that shows up just as often in Rockingham County wells and gets less conversation.

New Hampshire's own health standard for arsenic in drinking water is stricter than the federal one. The state lowered its limit from 10 parts per billion to 5 parts per billion, effective July 2021, specifically because long-term exposure at lower levels is still linked to cancer and cardiovascular disease. Statewide, roughly 30 percent of tested wells exceed the older federal limit, and southeastern New Hampshire, including Rockingham County, is consistently flagged as one of the higher-risk regions for this exact contaminant. Like radon, arsenic in bedrock wells has no taste, no smell, and no color. The only way anyone finds out is by testing, which is exactly why the water panel and the radon test are worth running together rather than treating radon as the whole story.

What Changed on January 1, 2025

New Hampshire's disclosure law is not static. Effective January 1, 2025, the legislature amended RSA 477:4-a to add PFAS and flood risk to the existing radon, arsenic, and lead notification language. PFAS, the so-called forever chemicals, have been detected in thousands of wells statewide, and the amendment means every Windham seller now hands buyers a notification that explicitly names PFAS alongside the contaminants that have been on the form for years.

The practical effect for anyone selling in Windham right now is that the topic surfaces earlier and more explicitly than it did even two years ago. A buyer who might have skimmed past a shorter radon-only notice in 2023 is now handed a form that names five separate risk categories in one document. That tends to prompt more questions during the inspection period, not fewer, which is worth anticipating rather than being caught off guard by.

How This Actually Plays Out in a Windham Contract

None of this typically derails a sale. Testing happens during the inspection period, usually paid for by the buyer as part of due diligence, though sellers who test ahead of listing can settle the question before it becomes a negotiation. If a result comes back above New Hampshire's standard, arsenic and radon are both treatable. Reverse osmosis and specific adsorptive filters handle arsenic. Aeration or a sub-slab depressurization system handles radon in air or water. The conversation that follows an elevated result is closer to a normal inspection negotiation, where the two sides settle on who installs a system and who pays for it, than it is to a reason to walk away.

The one place this becomes friction instead of a routine line item is when a buyer assumes the disclosure form already answered the question. It didn't. It only told them the question exists. The test is still theirs to order, and in a town built on the geology Windham sits on, it's one of the cheapest and most useful moves available before closing.

Frequently Asked Questions

Does Windham require radon or water testing before a home can be sold? No. New Hampshire does not mandate a specific test as a condition of sale. The seller notification under RSA 477:4-a is a warning that these contaminants can occur in the state, not proof that testing happened.

Who typically pays for the test? It's negotiable, and buyers most often order and pay for their own testing during the inspection period. When a lender requires a passing water test as a loan condition, sellers sometimes share or cover the cost.

If a test comes back elevated, does that kill the deal? Rarely. Both radon and arsenic are treatable with established mitigation systems, and an elevated result usually becomes a point of negotiation over who installs a system and who pays for it, similar to any other inspection finding.

Does a newer home in Windham need less testing than an older one? No. Radon and arsenic both originate in the granite bedrock beneath the property, not in the structure itself. Newer, tightly built homes can trap radon just as easily, sometimes more so, because of how airtight modern construction has become.

If you're weighing a purchase or a sale in Windham and want a clear read on what a specific property's inspection period is likely to surface, Key Team | Compass can walk you through it town by town. Get Your Free Home Valuation and we'll help you plan the inspection period before it plans you.