Selling a House With High Radon Levels
You can sell a house with high radon levels, but ignoring the problem can delay the transaction or cause a buyer to walk away. Sellers typically choose to install a mitigation system before closing, give the buyer a credit, or adjust the sale terms so the buyer can handle the work.
What Counts as a High Radon Level?
Radon is measured in picocuries per liter of air, written as pCi/L. The U.S. Environmental Protection Agency recommends taking corrective action when a home’s average radon level is 4.0 pCi/L or higher. It also suggests considering mitigation for results between 2.0 and 4.0 pCi/L.
A single result does not always tell the whole story. Radon levels can change with weather, ventilation, season, and testing conditions. Before making a major decision, confirm that the test was performed correctly and determine whether follow-up testing is appropriate.
For a real estate transaction, a qualified radon professional can use tamper-resistant equipment, document the testing conditions, and provide a report that buyers and agents are more likely to trust.
Can You Legally Sell a Home With High Radon?
In general, high radon does not make a home unsellable. There is no nationwide rule requiring every seller to reduce radon before transferring a property.
Disclosure requirements vary by state. Sellers may need to disclose known radon test results, existing mitigation systems, or other environmental conditions. Even where a specific radon disclosure is not required, general property-disclosure rules may apply.
Do not hide, remove, or misrepresent a previous result. That can create legal problems after closing and damage buyer confidence during negotiations. Ask your real estate agent or a local real estate attorney which forms and disclosures apply to your transaction.
Confirm the Result Before Negotiating
Start by reviewing how the high result was obtained.
Look for:
- The device type and testing dates
- The exact result in pCi/L
- The room and floor where the device was placed
- Whether closed-house conditions were maintained
- Whether severe weather or unusual ventilation affected the test
- Evidence that the device was moved or disturbed
Short-term tests commonly run for two to seven days. During a short-term test, exterior doors and windows should generally remain closed except for normal entry and exit. Fans that pull outdoor air into the home should not be operated unless they are part of the normal radon system.
If a short-term result is unexpectedly high and the closing schedule allows it, a follow-up test can provide more information. Avoid delaying urgent action solely to seek a lower number, especially when multiple properly conducted tests show elevated levels.
Your Options as a Seller
Install a mitigation system before closing
This is often the cleanest option. The most common approach, active soil depressurization, uses a pipe and fan to draw radon-containing soil gas from beneath the house and vent it above the roofline.
A standard residential system typically costs about $800 to $2,500, although large homes, crawl spaces, multiple foundations, difficult routing, and electrical work can raise the price. Installation often takes one day, with follow-up testing performed after the system has been operating.
Completing the work before closing gives buyers a finished solution and a post-mitigation result. It may also prevent repeated negotiations over an uncertain repair cost.
Offer the buyer a credit
A buyer credit can work when closing is approaching or the buyer wants control over the contractor and system design. Base the credit on one or more written estimates rather than guessing.
The purchase agreement should clearly state:
- The amount of the credit
- Whether the buyer accepts responsibility for mitigation
- Whether another test is required
- Any lender or appraisal conditions
- The deadline for completing the work
Some lenders limit credits or require health and safety concerns to be addressed before closing. Confirm the arrangement with the lender and closing professionals early.
Reduce the price or use an escrow
A price reduction may compensate the buyer, but it does not provide cash at closing to pay a contractor. An escrow holdback can reserve funds for post-closing work, although it requires agreement from the buyer, seller, lender, and closing agent.
These options are more complicated than installing a system, so document responsibilities and deadlines carefully.
Choosing a Radon Mitigation Contractor
Look for a professional certified through a recognized radon proficiency program and confirm whether your state requires a separate license. Ask for proof of insurance, a written scope of work, and a clear warranty.
A useful proposal should explain:
- Where the suction pipe and fan will be installed
- How crawl spaces or multiple foundation areas will be handled
- Where the system will discharge
- Whether electrical work is included
- The expected installation schedule
- How and when the home will be retested
- What happens if the first design does not lower the level enough
Red flags include guaranteed claims of “zero radon,” no plan for post-installation testing, an indoor fan location, unclear venting details, or pressure to proceed without a written estimate. Be cautious if the contractor does not inspect the foundation before quoting a complex home.
Find a certified radon professional near you
How Long Does Mitigation Take?
The full process can often fit within a normal inspection period:
- Estimate: Commonly one to several business days.
- Installation: Often completed in one day for a straightforward home.
- System stabilization: Follow the contractor’s instructions before retesting.
- Post-mitigation test: Usually another two to seven days for a short-term test.
- Corrections, if needed: Additional sealing or suction points may add several days.
Build extra time into the contract for contractor availability, weather, electrical permits, and follow-up work. Keep the installation invoice, warranty, system diagram, operating instructions, and all test reports for the buyer.
FAQ
Will high radon make a buyer cancel the sale?
It can, particularly if the seller refuses to address it. Many buyers continue once they receive a credible mitigation plan, reasonable credit, or successful post-mitigation result.
Should I test before listing my house?
A pre-listing test can reveal the issue before a buyer’s inspection and give you time to compare contractors. Use proper testing conditions and keep the report because known results may need to be disclosed.
Who usually pays for radon mitigation?
It is negotiable. Sellers often pay or provide a credit in buyer-friendly markets, while buyers may accept responsibility when competition is strong. The contract should state the agreement clearly.
Does a mitigation system hurt resale value?
Usually, a professionally installed and documented system is viewed as a solution rather than a defect. Buyers may still request a new radon test to confirm that the system is operating effectively.