Who Pays for Radon Mitigation: Buyer or Seller?

There is no universal rule that makes either the buyer or seller pay for radon mitigation. Payment is usually negotiated through the purchase contract: a seller may install a system, offer a credit or price adjustment, or decline, leaving the buyer to accept the cost or exercise any available contingency rights. State and local laws, contract language, and lender requirements can affect the outcome, so verify the current rules for the property’s jurisdiction.

How responsibility is decided

The practical answer depends on what the parties agreed to before testing and what the contract allows after an elevated result.

The EPA recommends testing homes during a sale and fixing a home when the radon level is 4 picocuries per liter (pCi/L) or higher. However, this is federal health guidance—not a nationwide rule assigning the bill to one party. The EPA’s Home Buyer’s and Seller’s Guide to Radon specifically encourages buyers and sellers to put provisions in the contract covering the test, sharing of results and costs, when mitigation will occur, and who will pay.

Common negotiated outcomes include:

• The seller hires and pays a radon contractor before closing.
• The seller provides a closing credit or price reduction, subject to lender and closing rules.
• The buyer accepts the property and installs a system after closing.
• The parties divide the cost.
• The buyer terminates or renegotiates under a valid inspection, radon, or due-diligence contingency.

A seller is more likely to pay when the buyer has a clear contractual remedy, the result is well documented, or the seller wants to preserve the transaction. A buyer may prefer a credit when they want to select the contractor and control the system’s design. The strongest arrangement is the one documented in a signed amendment—not an informal promise.

The process after a high radon result

First, confirm that the measurement is suitable for a real estate decision. Review who conducted the test, the device used, its placement, test conditions, dates, and any evidence of interference. The EPA recommends testing in the lowest level that could be used regularly, even if it is unfinished.

Next, read the contract before discussing payment. Identify:

• The inspection or radon-contingency deadline
• Any threshold or remedy written into the agreement
• Notice and documentation requirements
• The buyer’s rights to request repairs, negotiate, or terminate
• Whether credits are restricted by the lender or settlement structure

Then obtain a written mitigation proposal from a qualified provider. A proposal gives the parties a defined scope to negotiate rather than an unsupported allowance. For background on system design, see how a radon mitigation system works.

If the seller will complete the work, the amendment should identify the contractor-selection standard, scope, payment responsibility, completion point, warranty documents, and post-mitigation testing. If the buyer will complete it later, specify the exact credit or adjustment and confirm that the lender and closing professionals can implement it.

Edge cases that change the negotiation

The seller already has a mitigation system. Ask for the installation contract, warranties, maintenance history, prior test reports, and a current test. A system’s presence does not prove that current radon levels are low.

The result is close to 4 pCi/L. EPA recommends fixing at 4 pCi/L or higher and says levels below 4 pCi/L still carry risk and may sometimes be reduced. Do not treat 4 pCi/L as a line between “dangerous” and “safe.” Read more about what a 4.0 pCi/L result means.

The test may be unreliable. Incorrect placement, failure to maintain required test conditions, disturbed equipment, major weather events, or an undocumented device can justify consultation with a qualified tester. Do not casually repeat tests until a preferred number appears; follow the applicable professional protocol and transaction timeline.

It is a newly built home. Radon-resistant construction does not replace testing. The EPA’s new-home radon guidance recommends testing after occupancy and activating a passive system with an in-line fan if the result is 4 pCi/L or above. Responsibility for that work may depend on the construction contract, builder commitments, warranty terms, code, and local law.

The home is a condominium or has shared structures. Mitigation may involve common elements, exterior alterations, roofs, or association approval. Determine ownership and approval responsibilities before agreeing on a remedy.

Closing is near. Installation may not fit the remaining schedule. An escrow arrangement, credit, or post-closing agreement may be possible, but it must be approved and drafted by the appropriate real estate, legal, lending, and settlement professionals.

What buyers and sellers should ask

Ask the tester:

• Was the device approved or accepted under the applicable state program?
• Was it placed in the lowest level that could be regularly occupied?
• Were required test conditions followed?
• Does the report show possible interference or unusual readings?
• Does state law require a particular protocol or credential?

Ask the mitigation contractor:

• What system is proposed for this foundation type?
• Are permits or inspections required?
• Does the scope include a system-failure warning device and post-installation testing?
• Who repairs damage and completes cleanup?
• What warranties apply, and are they transferable?
• What ongoing electricity, maintenance, or retesting should the owner expect?

The EPA’s Consumer’s Guide to Radon Reduction recommends a written contract describing the work, total cost, permits, completion time, warranties, any performance commitment, and post-installation testing.

Search the certified radon provider registry

Red flags during a transaction

Be cautious if someone:

• Claims federal law always requires the seller—or buyer—to pay
• Dismisses an elevated result because neighboring homes tested lower
• Offers mitigation without inspecting the home or considering its foundation
• Proposes sealing cracks as the only remedy without explaining the full system design
• Refuses to provide a written scope, warranty terms, or post-mitigation test
• Wants the seller, agent, or occupant to control a test without safeguards against interference
• Promises a specific result without stating conditions and remedies in writing
• Treats a passive new-construction pipe as proof that the home has acceptable radon levels

EPA guidance is national, while licensing, disclosure, testing, building-code, and mitigation requirements may be established by states or local governments. Verify current requirements with the state radon office and qualified local real estate or legal professionals.

Records to keep

The buyer should receive copies of:

• All radon reports, including device details and test locations
• The mitigation proposal and final paid invoice
• Signed inspection responses and contract amendments
• Permit and inspection records, when applicable
• A diagram or description of the installed system
• Fan, equipment, and workmanship warranties
• The post-mitigation test report
• Operating and maintenance instructions
• Any transferable service agreement

Sellers should retain the same materials for disclosure and future questions. EPA guidance advises sellers to preserve test results and information about corrective work. Buyers can also review this guide to radon testing during a home inspection before deciding whether an older report is adequate.

A practical negotiation checklist

1. Confirm the test’s validity and applicable protocol.
2. Check the contract’s deadlines and remedies immediately.
3. Verify state and local disclosure, credential, and mitigation rules.
4. Obtain a written proposal from a qualified contractor.
5. Decide whether installation before closing or a buyer-controlled credit is preferable.
6. Confirm any credit or escrow structure with the lender and closing professional.
7. Put the complete agreement in a signed contract amendment.
8. Require post-mitigation testing and transfer all system records.

Does a seller have to pay for radon mitigation?

Not automatically. A seller’s responsibility depends on the purchase contract and any applicable state or local requirement. Otherwise, payment is negotiable.

Can a buyer ask for a radon mitigation credit?

Yes. The parties may negotiate a credit or price adjustment, but the lender and settlement professional should confirm whether and how it can be applied.

Who chooses the radon mitigation contractor?

The contract or repair amendment should say. Buyers may prefer to choose the provider; sellers who pay before closing may expect to manage the work, subject to agreed qualification and performance terms.

Should mitigation be completed before closing?

It can be, but it is not the only option. Consider the contingency deadline, installation and retesting schedule, contractor availability, lender rules, and whether the buyer wants control over the final system.