Should I get a radon test when buying a house?

Yes, in almost every case. It is inexpensive relative to the purchase, it is the only way to know the level, and a high result is a routine, fixable negotiating item rather than a deal-breaker. The EPA recommends testing for all real-estate transactions.

Can a seller refuse a radon test?

A seller can refuse to allow it, but in most markets that is a red flag buyers walk away from. Buyers can make the offer contingent on a radon test with the right to cancel or renegotiate above 4 pCi/L.

Who pays for radon mitigation in a home sale?

It is negotiated. Common outcomes: the seller installs a system before closing with a post-mitigation test, the seller credits the buyer roughly the typical cost, or the buyer accepts the level. There is no federal rule assigning the cost.

Does radon have to be disclosed?

Rules vary by state. Many states require sellers to disclose known radon test results or the presence of a mitigation system on the property disclosure form; a few require specific radon disclosure language. Check with your state radon program or a local agent.

Radon and real estate: what buyers and sellers need to know

Radon shows up in more home sales than any other environmental issue, because it is common, invisible and cheap to test for. Handled early it is a line item; discovered late it delays closings. Here is how the radon step works in a transaction, what the rules generally look like, and how each side should approach it. Start by looking up the property's ZIP-level predicted radon and its county's EPA zone - that tells you how likely a test is to come back high.

For buyers

Make the test part of the inspection period

Add a radon contingency to the offer alongside the general inspection. A professional short-term test takes 48 hours minimum, so schedule it at the start of the inspection window, not the end. Most buyers hire the home inspector or a certified radon measurement professional to place a continuous monitor; the report shows hourly readings, so any tampering (opened windows, moved device) is visible.

Test the right place, under the right conditions

The device goes in the lowest level that could be lived in - a basement, finished or not, if a future owner might use it. Closed-house conditions must hold for 12 hours before and throughout. The seller is normally asked to sign a non-interference agreement. A vacant house can be tested the same way; the result still counts.

What to do with the result

Below 2 pCi/L: proceed. Re-test after you move in and after any renovation.
2-4 pCi/L: the EPA says "consider fixing." Plan a long-term test once you own it; some buyers negotiate a small credit.
4 pCi/L or higher: ask the seller to install a mitigation system before closing with a post-mitigation test below 4 (ideally below 2), or to credit the typical cost ($800-$2,500) at closing. Both are routine requests in high-radon regions.

A high reading is not a reason to walk away on its own: mitigation is reliable and modest in cost relative to the purchase. What matters is that it is done by a certified installer and verified with a test.

For sellers

Test before you list

A pre-listing test removes the surprise. If the result is low, you disclose it and move on. If it is high, you can install a system on your own schedule and choice of contractor - which is almost always cheaper than a rushed fix under a closing deadline with the buyer's installer. Then list the house as "radon mitigated, tested at X pCi/L," which in many markets is a selling point.

Disclose what you know

Most states require sellers to disclose known material facts, and many property-disclosure forms ask specifically about radon tests and mitigation systems. Some states require particular radon language or a pamphlet. Failing to disclose a known high result invites a lawsuit later; disclosing a mitigated system does not scare buyers. Confirm your state's rules with your agent or the state radon office.

If you already have a system

Keep the installer's invoice, the system diagram and every test result in one folder for the buyer. Check that the manometer shows suction and that the fan runs. If the last test is older than two years, run a new one before listing.

New construction and radon-resistant building

Many jurisdictions in EPA Zone 1 counties require or encourage radon-resistant new construction (RRNC): a gravel layer and vapor barrier under the slab, sealed penetrations, and a capped vertical vent pipe from sub-slab to roof. A passive stack lowers radon somewhat, and a fan can be added later for the cheapest possible active system. A new home is not automatically low - test it like any other house. Ask the builder whether RRNC features were installed and where the stack is capped.

Rental property

Landlord obligations vary widely by state and city; a handful require disclosure of known results to tenants, and some require testing in certain buildings. Tenants can test their own unit with a kit. Because the tenant, not the owner, bears the exposure, a low-cost test is worth doing in any ground-floor or basement unit regardless of what the lease requires.

Finding certified professionals

For transactions, use measurement and mitigation professionals certified by NRPP or NRSB and licensed in your state, located through the EPA's find-a-professional page. For the mechanics of the test itself, see how to test; for what a fix involves, see mitigation.

Radon in real estate FAQ

Should I get a radon test when buying a house?: Yes, in almost every case. It is inexpensive relative to the purchase, it is the only way to know the level, and a high result is a routine, fixable negotiating item rather than a deal-breaker. The EPA recommends testing for all real-estate transactions.
Can a seller refuse a radon test?: A seller can refuse to allow it, but in most markets that is a red flag buyers walk away from. Buyers can make the offer contingent on a radon test with the right to cancel or renegotiate above 4 pCi/L.
Who pays for radon mitigation in a home sale?: It is negotiated. Common outcomes: the seller installs a system before closing with a post-mitigation test, the seller credits the buyer roughly the typical cost, or the buyer accepts the level. There is no federal rule assigning the cost.
Does radon have to be disclosed?: Rules vary by state. Many states require sellers to disclose known radon test results or the presence of a mitigation system on the property disclosure form; a few require specific radon disclosure language. Check with your state radon program or a local agent.

This guide is general information, not legal advice. Disclosure and licensing rules differ by state; confirm yours before relying on them. Follows EPA's Home Buyer's and Seller's Guide to Radon.