Do I Need Radon Mitigation to Sell My House?

Usually, you are not automatically required to install a radon mitigation system before selling your house. However, state disclosure laws, local rules, your sales contract, or the buyer’s lender may affect what you must do—and a high radon result can become an important negotiation issue.

Is Radon Mitigation Legally Required Before a Sale?

There is no general federal law requiring every seller to test for or mitigate radon before selling a home. Requirements vary by state and sometimes by city or county.

Depending on where you live, you may need to:

• Disclose known radon test results
• Provide a radon information notice
• Answer questions about previous testing or mitigation
• Give the buyer time to conduct a radon test
• Follow specific testing rules during a real estate transaction

A seller generally should not hide, remove, or misrepresent a known radon result. Even where testing is optional, disclosure laws may require you to share results you already have.

Your purchase agreement matters too. A buyer may include a radon contingency allowing them to test the home and request repairs, renegotiate the price, or cancel the contract if the result exceeds an agreed level.

For requirements specific to your sale, consult your real estate agent or a local real estate attorney.

What Radon Level Calls for Action?

Radon is measured in picocuries per liter of air, written as pCi/L. The EPA recommends fixing a home when the radon level is 4 pCi/L or higher. It also suggests considering mitigation when results fall between 2 and 4 pCi/L.

A result at or above 4 pCi/L does not necessarily mean you must install a system immediately to complete the sale. It does mean the buyer is likely to raise the issue.

Because radon levels can fluctuate, follow-up testing may be appropriate. Real estate tests are often short-term tests lasting at least 48 hours. If the first result is close to the action level, the parties may agree to repeat the test or use a different testing method before making a decision.

Testing devices should be placed in the lowest level that could be regularly occupied, following the device manufacturer’s instructions and applicable real estate testing protocols.

Your Options After a High Radon Test

When a test shows elevated radon, sellers usually have several options.

Install a mitigation system before closing

This gives the buyer a completed solution and may make the transaction easier to finish. The agreement should specify whether post-installation testing is required and what happens if the system does not lower the level sufficiently.

Offer a credit or reduce the price

A buyer may prefer to choose their own contractor after closing. Before agreeing to a credit, obtain one or more written estimates so the amount reflects the likely cost.

Lenders and appraisers may not treat repair credits the same way, so both parties should confirm that the arrangement works with the buyer’s financing.

Put money in escrow

The parties can sometimes reserve funds at closing for mitigation work afterward. This requires a clear written agreement covering the amount, deadline, contractor selection, testing, and release of funds.

Decline the request

If mitigation is not legally or contractually required, you may be able to sell without making the repair. The buyer could still cancel if their inspection contingency permits it, and you may need to disclose the known result to future buyers.

How Much Does Radon Testing and Mitigation Cost?

Professional radon testing for a typical home often costs about $150 to $300, although larger homes, multiple test locations, expedited service, and local market rates can increase the price.

A standard residential mitigation system typically costs around $800 to $2,500. More complicated projects may cost $3,000 or more. Price can depend on:

• Foundation type, including basement, slab, or crawl space
• Home size and layout
• Number of suction points required
• Crawl-space sealing
• Fan location and exhaust routing
• Electrical work
• Permit requirements
• Cosmetic preferences for visible piping

The most common approach is active soil depressurization. A contractor installs piping and a continuously operating fan to draw radon-containing soil gas from beneath the house and discharge it safely outdoors.

Ask whether the proposal includes permits, electrical work, system labeling, a pressure indicator, warranties, and a post-mitigation test. Comparing estimates by scope—not just total price—helps prevent unexpected charges.

How Long Will Mitigation Delay the Sale?

A radon test generally requires at least 48 hours, although scheduling and report preparation can add several days. Many straightforward mitigation systems can be installed in one day once the contractor is available.

Post-mitigation testing adds more time. The system should be operating before the confirmation test begins, and the test itself commonly takes at least another 48 hours. In a busy market, contractor availability may be the longest part of the process.

If closing is approaching, put every deadline in writing. Identify who will hire the contractor, pay the invoice, receive the report, and approve the completed work.

Choosing a Qualified Radon Professional

Look for a professional certified through a recognized national radon proficiency organization or licensed under your state’s program, where applicable. Certification should cover the actual service being performed; testing and mitigation may require different credentials.

Ask prospective professionals for:

• An active certification or license number
• Proof of insurance
• A written scope and itemized price
• References or verified customer reviews
• Details about warranties and follow-up testing
• An explanation of where the fan, pipe, and exhaust point will go
• Confirmation that the design follows applicable standards

Find a certified radon professional near you

Red flags include guarantees made without inspecting the home, pressure to skip post-installation testing, unclear subcontracting, unusually low quotes that exclude electrical work, and exhaust plans that terminate near windows or other building openings.

Practical Steps for Sellers

First, review your state’s disclosure form and your purchase agreement. Gather any previous radon reports, mitigation invoices, warranties, and maintenance records.

If a new test is needed, use a qualified tester and avoid disturbing the device. Follow closed-house conditions when required, including keeping exterior doors and windows closed except for normal entry and exit.

If the result is elevated, obtain written mitigation estimates promptly. Decide whether installation, a credit, or escrow best fits the contract and closing schedule. After mitigation, arrange an independent test to confirm performance and give the buyer copies of the system documents.

FAQ

Can a buyer cancel a sale because of radon?

Possibly. A buyer may be able to cancel if the contract includes an inspection or radon contingency and its deadlines and conditions are met. Without that right, the answer depends on the contract and local law.

Does a radon system hurt resale value?

Usually, a properly installed system is viewed as a solution rather than a defect. Documentation showing professional installation and a low follow-up result can reassure buyers.

Can I test for radon myself before listing?

Yes. A home test kit can provide useful preliminary information. For a real estate transaction, however, an independent certified tester may produce a result that buyers are more willing to accept.

Do homes without basements need radon testing?

Yes. Radon can enter homes built on slabs, crawl spaces, and basements. The home’s foundation type does not reliably show whether its radon level will be high.