Condition
How to Sell a House Affected by Radon Gas
Radon is a naturally occurring radioactive gas found at higher levels in some UK areas. A home in a radon-affected area can be sold normally — the keys are to test the radon level, install simple, effective mitigation if it is high (a sump or improved ventilation), disclose the position, and reassure buyers with the test results. Radon rarely stops a sale or mortgage, and where speed matters a cash buyer completes in 7-28 days.
What is your property worth?
Get genuine offers from checked & vetted buyers.
- Testthe real level
- Sumpcuts high levels
- 7-28 dayscash as-is
What radon is and where it occurs
Radon is a colourless, odourless radioactive gas produced naturally by the breakdown of uranium in rocks and soil. It is present everywhere at low levels, but in certain geological areas (parts of the South West, the Pennines, and other regions) it can accumulate in buildings to higher levels. Long-term exposure to high radon is a health risk (it is a known cause of lung cancer), which is why affected areas and high readings matter — but it is testable and treatable.
Testing for radon
A buyer’s environmental search will reveal whether the property is in a radon-affected area, and you can carry out a simple radon test (detectors placed for a period, then analysed) to measure the actual level in your home. Knowing the real reading is valuable: many homes in "affected areas" test below the action level and need nothing done, and a test result is reassuring evidence for buyers. The UK Health Security Agency provides radon information and testing.
Reducing high radon levels
| Measure | Detail |
|---|---|
| Radon sump | A fan-driven sump under the floor — very effective |
| Improved ventilation | Increasing under-floor or whole-house ventilation |
| Sealing floors | Reducing entry points for the gas |
Mitigation is generally straightforward and affordable, and a sump in particular can dramatically cut radon levels — turning a high reading into a non-issue.
Disclose and reassure
If you know the property is in a radon-affected area or has tested high, disclose it on the property information form, along with any test results and mitigation installed. This is exactly what reassures buyers: a test showing a low level, or evidence of effective mitigation, removes the worry. Radon is well understood and manageable, and honest information with results keeps a sale on track far better than leaving buyers to fear the unknown.
Selling fast
Radon rarely affects mortgageability, so an affected home usually sells normally with testing and (if needed) mitigation. If you would rather not test or mitigate, or you need speed, a cash buyer will purchase the home as-is and complete in 7-28 days. You disclose the position, accept a price reflecting it, and gain certainty.
Don’t accept a lowball offer for your home
Compare genuine cash offers and investor options in minutes — free, no obligation, no fees.
Written & reviewed by Lisa Hayes, Founder
Lisa Hayes is the founder of Ready Steady Sell and an independent UK home-selling expert with over a decade helping homeowners weigh cash house buyers, property investors and the wider fast house-sale industry — without pressure or hidden fees. Every guide is reviewed for accuracy under our editorial standards.
LinkedIn · Expert commentary · In the media · Industry statistics
Frequently asked questions
Straight answers, no sales talk
Can I sell a house with radon?
Yes. Test the level, install simple mitigation if it is high, disclose the position, and reassure buyers with the results. Radon rarely stops a sale or mortgage.
What is radon and is it dangerous?
A naturally occurring radioactive gas, higher in some areas. Long-term exposure to high levels is a health risk (lung cancer), but it is testable and treatable.
How do I test for radon?
Place radon detectors in the home for a period and have them analysed. A buyer’s environmental search also reveals whether the property is in a radon-affected area.
How do I reduce high radon levels?
Usually with a radon sump (a fan-driven sump under the floor), improved ventilation, or sealing floors. Mitigation is straightforward and affordable, and a sump is very effective.
Do I have to disclose radon when selling?
If you know the property is in a radon-affected area or has tested high, disclose it on the property information form, with any test results and mitigation installed.
How fast can I sell a radon-affected house?
An affected home usually sells normally with testing and mitigation; a cash buyer can complete in 7-28 days if you need speed.