Do You Need a Radon Test Before Selling Your Massachusetts Home?

Radon isn't something most homeowners think about until it shows up as a line item during a home sale. Here's what to know before you're in the middle of a transaction.

Is testing required in Massachusetts?

Massachusetts doesn't mandate radon testing or disclosure by state law the way it does for Title 5 septic inspections, but most buyer's home inspectors will recommend or perform a radon test as a standard part of the inspection process, especially since Middlesex County sits in an area with a meaningful share of homes testing above the EPA's action level.

What's the actual risk level?

The EPA recommends taking action if radon levels test at or above 4 picocuries per liter (pCi/L). Radon is a naturally occurring radioactive gas that seeps up from soil and rock, and levels can vary significantly even between neighboring homes depending on foundation type, soil composition, and ventilation — a finished basement with a sump pit is a common entry point.

What happens if a buyer's test comes back high

If a buyer's inspection reveals elevated radon, it commonly becomes a negotiation point — the buyer may ask the seller to install a mitigation system, offer a credit, or share the cost. Having your own test done and, if needed, a mitigation system installed before listing can prevent this from derailing a deal or a closing timeline.

What mitigation actually involves

Most residential radon mitigation systems use a sub-slab depressurization approach — a vent pipe and fan system that draws radon from beneath the foundation and releases it safely above the roofline. Installation is typically a one-day job for a standard single-family home, and effectiveness is usually confirmed with a follow-up test.

The bottom line

Testing is inexpensive relative to the risk of a mitigation surprise mid-sale. If you're planning to sell within the next year, getting ahead of it is usually the cheaper and less stressful path.

This is general information, not a substitute for a certified radon measurement or mitigation professional's assessment.