How to Test for Radon in New Construction

On this page (8 sections)

1. When should you test for radon in new construction?
2. Where should a radon test go in a newly built home?
3. How do you test while keeping the home closed?
4. What if the builder installed a radon reduction system?
5. Which test kit can you use in a new home?
6. What should you do if the result is higher than recommended?
7. How often should you retest a new home?
8. What is the practical testing plan for new construction?

For radon testing in new construction, wait until the home is ready for normal occupancy, then test the lowest lived-in level with a short-term kit or a qualified measurement professional. Follow the test instructions and maintain any required closed-house conditions.

A new foundation or radon-resistant features can't tell you the finished home's radon level. Test after construction is complete, and test again once any installed radon reduction system is running.

When should you test for radon in new construction?

Test after construction is complete and the home can be kept under the test's required conditions. That gives you a reading in the home as it will be used, rather than during an open or unfinished construction phase.

Wait until windows, doors, and heating or cooling systems are in their normal operating state. Follow the kit or professional's instructions about closed-house conditions, including how long to maintain them before and during the test.

If a builder has installed a radon reduction system, have it operating as intended before testing. A test taken before the system is running won't show how well the completed setup is working.

Testing can also be part of a sale or move-in plan. See when radon testing is necessary for other situations that call for a new measurement.

Where should a radon test go in a newly built home?

Place the test in the lowest level that could be used regularly, such as a finished basement or a ground-floor room when there is no basement. Use the room and placement instructions that come with the test.

Keep the device away from drafts, direct sunlight, high humidity, exterior walls, and areas where it could be disturbed, unless its instructions say otherwise. Don't place it in a kitchen, bathroom, closet, or other excluded location.

If the basement is unfinished, ask the testing professional or follow the kit's guidance on whether it qualifies as a regularly used space. A measurement in the wrong location may not reflect the level where people spend time.

How do you test while keeping the home closed?

Set up the test only after meeting its closed-house requirements, then leave the home in those conditions for the full measurement period. A radon test in progress notice can remind occupants to maintain those conditions.

Don't open windows or exterior doors for extended periods during the test.

Short-term tests usually take a few days, but the exact exposure window depends on the test method. Keep the device in place and avoid moving it, covering it, or placing it near fans or vents.

For a basic overview of test methods and steps, read How to Test for Radon: The Simple Answer. The beginner's guide to what radon testing is explains what a measurement can and cannot tell you.

Is a short-term test enough for a new home?

A short-term test can provide an initial screening, but one reading may not answer every question about long-term exposure. Follow the test instructions and local guidance if a result is near an action threshold or if conditions during testing were not typical.

A longer measurement can reflect more day-to-day variation. Learn what a long-term radon test is if you want to understand that option.

What if the builder installed a radon reduction system?

Test the home after the system is operating to check the resulting radon level. Ask the builder for system documents, operating instructions, and any recommended retest schedule.

Don't assume that a pipe, fan, sealed opening, or other visible feature means the system is reducing radon as intended. A measurement checks the indoor air, while a qualified professional can inspect the system's installation and operation.

Keep records of the test date, test location, result, and system status. If the system has an indicator or maintenance instructions, follow them and arrange service if the system is not operating as directed.

Which test kit can you use in a new home?

Use a kit that fits your schedule and follow its instructions exactly. These options use laboratory analysis, so check the exposure period, return steps, and result timing before starting.

The First Alert kit includes test materials and lab fees, except New Jersey state fees, and results are emailed within 72 hours of lab receipt. It is recommended for use only in the United States.

The PRO-LAB kit uses a 48-hour collection period and includes lab analysis. It also offers email or text updates, according to its product details.

The Leaping Lynx kit is a 48-hour short-term test with lab analysis included; return postage is required. Its instructions call for placement on the lowest livable level.

For a broader overview of kit formats, see what a radon test kit is. A qualified measurement professional may be a better fit if you need help meeting test conditions or documenting a result for a transaction.

What should you do if the result is higher than recommended?

Follow current public health guidance and arrange a reliable follow-up measurement or mitigation review. A single result is a reason to understand the level and next steps, not to guess based on the home's age or construction.

Use a qualified radon professional when you need confirmation, system inspection, or help choosing a mitigation approach. Keep the test report and any system records together so future checks can be compared.

Don't cover or adjust a mitigation system based on a test result without professional guidance. Continue testing at the interval recommended for your location and system.

How often should you retest a new home?

Retest after installing or changing a radon reduction system, and follow the schedule recommended by local authorities or the qualified professional. A new test may also be needed after major renovations or changes that affect the foundation or ventilation.

Homes change over time, so the first measurement is not a permanent guarantee. For a practical schedule, see how often you should test for radon.

What is the practical testing plan for new construction?

For radon testing in new construction, test once the home is complete and under the test's required conditions. If a system is installed, run it as intended before measuring, then keep the result and system records.

Choose a short-term kit for an initial screen when you can follow its instructions, or use a qualified professional when you need help with placement, confirmation, or documentation. Retest when the system or home changes and at the interval advised for your area.

Frequently asked questions

When should you test for radon in a new home?

Test after construction is complete and the home can be kept under the closed-house conditions required by the test instructions. If a radon reduction system is installed, test after it is operating as intended, then follow local guidance for any additional testing.

Can new construction still have radon?

Yes. Radon can enter homes through openings and joints in contact with the ground, so a new build can have raised indoor levels.

Construction features or a radon-resistant system do not replace a test; measure the home to learn its actual level.

Where should I put a radon test in a new house?

Place the test in the lowest level that could be used regularly, following its instructions for room choice, height, and distance from drafts or windows. Avoid kitchens, bathrooms, closets, and other locations excluded by the test directions.

Should I test again after installing a radon system?

Yes. Test after the system is installed and operating to check the home's radon level, and keep any follow-up schedule required by local rules or the system professional.

Test again after major changes to the system or home, or if a later test is due.