Test4 min read

Is a radon test required?

By Radon411 Editorial TeamUpdated October 1, 2026How we research

Short answer

Testing is recommended for every home below the third floor, but whether it is legally required depends on your state and local rules and on the terms of a home sale. Some states require disclosure of radon information to buyers, specific testing protocols, or licensed radon professionals.

Next step: pick the right test for your home. Which test to use

EPA and the Surgeon General recommend testing all homes below the third floor, and testing is the only way to know if you and your family are at risk. A recommendation is not the same as a legal requirement.

In a home sale, sellers are advised to test before listing and buyers to know the level of any home they consider buying. A buyer may ask for a new test if your state or local government requires disclosure of radon information, and the contract can require a test and set where, when and by whom it is done.

How tests are done can be regulated: some states require testers to follow a specific protocol, many require radon professionals to be licensed, certified or registered, and local building codes may require radon-resistant features in new homes.

What to do next: look up your state's radon program for local rules, and if you are buying or selling, agree on the test in writing before it starts.

Recommended everywhere, required in some cases

A radon test is strongly recommended for every home below the third floor: EPA and the Surgeon General recommend testing all of them, and testing is the only way to know if you and your family are at risk. Whether a test is legally required depends on your state and local rules and on the terms of a home sale.

Where radon rules can come from
Source	What it can cover
National recommendation	Testing all homes below the third floor, and schools
State or local disclosure rules	Some require radon information to be disclosed to buyers
State testing rules	Some require testers to follow a specific testing protocol
State licensing	Many require radon professionals to be licensed, certified or registered
Building codes	Some state or local codes require radon-resistant features in new homes
The sale contract	Where, when, how and by whom a test is done

Radon tests and home sales

If you are buying or selling a home, have it tested. Sellers are advised to test before putting a home on the market, and buyers to know the indoor radon level of any home they consider buying; if the home has not yet been tested, have it tested. A buyer may also ask for a new test if your state or local government requires disclosure of radon information.

EPA's three short-term radon testing options for a real estate transaction: two tests at the same time, one test then a second, or a continuous monitor, each for at least 48 hours, with what to do after each. — The three short-term testing options for a home sale.

See radon disclosure requirements.

Writing the test into the contract

Even where no law requires a test, the parties can require one in the purchase contract. Consider including provisions that settle the details before anyone tests.

Contract provisions for a radon test
Provision	What it settles
Location	Where the test will be located
Tester	Who should conduct the test
Type and timing	What type of test to do, and when
Results and costs	How the seller and buyer share the test results and costs
Mitigation	When radon mitigation will be done, and who will pay

Rules for testers

How a test is done can be regulated even where testing itself is not required. Some states require radon measurement testers to follow a specific testing protocol, and many require radon professionals to be licensed, certified or registered. In states that do not regulate radon services, ask whether the tester holds a professional proficiency or certification credential.

New homes and inspections

Every new home should be tested after occupancy, even if it was built radon-resistant, and building codes in your state or local area may require radon-resistant features. A radon test can also be part of a home inspection: a qualified radon tester is very often a home inspector.

Why test even when no rule requires it

All outdoor and indoor air has some radon in it, and breathing in high levels of radon over time may cause lung cancer. Testing is the only way to know if you and your family are at risk, which is why the recommendation covers every home below the third floor whether or not a law applies. You can test yourself, or, especially when buying or selling, hire a qualified tester.

Questions about whether radon testing is required

Is radon testing required by law?

Testing is recommended for every home below the third floor. Legal requirements depend on your state and local rules and on the sale contract.

Is a radon test required to sell a house?

Sellers are advised to test before listing, and some states and localities require radon information to be disclosed to buyers.

Is radon testing recommended for schools?

Yes. EPA also recommends testing in schools.

Who can tell me my state's radon rules?

Your state radon office, which can also help you find qualified radon professionals.

Can I test my home myself?

Yes. You can also hire a qualified tester, especially when buying or selling a home.

Do radon testers need a license?

Many states require radon professionals to be licensed, certified or registered, and some require a specific testing protocol.

Is radon testing required for new construction?

Every new home should be tested after occupancy, and local building codes may require radon-resistant features.

Test

How a radon test works, who can run one, and how to read the number it gives you.

Everything in Test Other guide topics

16 min read
Radon inspection
How a professional radon test works, what it proves and whether it is worth it.
Read the guide
17 min read
High radon levels
What counts as high and how to bring them down.
Read the guide
16 min read
Radon limits
EPA's action level, WHO's reference level and what counts as acceptable.
Read the guide