Radon is one of the few inspection findings that can genuinely hold up a Hunterdon County closing — not because it is hard to fix, but because it arrives late, has a number attached, and nobody has agreed in advance who owns it.
What the law actually requires
New Jersey does not require every home to be tested for radon before it changes hands. What it does require is that a seller who has test results gives them to the buyer. In practice, radon testing is a routine part of home inspections across Hunterdon County, so on most transactions here a number appears whether or not anyone planned for one.
There is a second requirement that catches people out on rural properties. Under the Private Well Testing Act, a home served by a private well has to have its water tested at the point of sale, and gross alpha is a required parameter for Hunterdon County wells — a screening measurement that can indicate radon and other radioactivity in the water. Hunterdon is one of the counties where this has been required in the northern part of the state, alongside Mercer and Somerset. So a rural sale here can produce two separate radon-related findings from two separate tests.
Why the timing is the problem
A valid short-term test needs at least 48 hours of closed-house conditions, and it needs to be placed and collected by a certified measurement business. That is two or three days minimum before anyone has a number, and it usually happens during the inspection window — which is exactly when everyone is already negotiating everything else.
Then the result is a number, not an opinion. "Some settling cracks" is arguable; "9.4 pCi/L" is not. That clarity is good for homeowners and awkward for deals, because it converts immediately into a demand.
Who pays
There is no rule. In practice, on Hunterdon transactions, a few patterns recur: the seller installs a system before closing; the seller credits the buyer an agreed amount at closing and the buyer arranges it afterwards; or the parties split it. Which one happens is a function of the market and the negotiation, not of the law.
What makes any of them go smoothly is having a real number for the work rather than a guess. A written quote from a certified mitigation business, with the number of suction points and the scope in it, turns an open-ended worry into a line item — and a line item can be negotiated.
The thing sellers get wrong
Testing early. If you are listing a Hunterdon County house, a test before you go to market costs a few hundred dollars and removes the single most disruptive surprise from the inspection period. If it comes back high, you fix it on your own schedule, at your own choice of contractor, and you market the house with a mitigation system and a clearance test as a feature rather than conceding it under time pressure. If it comes back low, you have documentation.
The thing buyers get wrong
Accepting a system with no clearance test behind it. "There's a radon system" is not the same as "the house reads below 4.0." If a system is already installed, ask for the post-mitigation test result. If there isn't one, that is a reasonable thing to ask for during the inspection period, and it is cheap.
Agents and inspectors
If a radon finding lands on a deal with a date on it, send it over. We will put it in front of certified crews who work that town and can act on the timeline, and if nobody realistically can, we will tell you that rather than burn a week of your inspection period. There is no fee and no referral arrangement in either direction — we are paid by contractors, not by you, and we do not pay for referrals.
Send us an inspection finding with the closing date
Free, no obligation, and we are not a contractor — we pass what you tell us to NJDEP-certified businesses that cover your town.
Get free quotes →General information for Hunterdon County, NJ property owners — not a diagnosis, not a quote, and not a reading for any particular building. Every property is different; a certified professional confirms specifics on site.