Radon Testing: Is Your House in a Radon Affected Area?
If your conveyancing search has flagged a Radon Affected Area, you are rightly concerned. Radon is a serious, proven health risk, classified as the second leading cause of lung cancer in the UK, responsible for approximately 1,100 deaths annually (UK Health Security Agency).
Your immediate issue is the property purchase timeline: a proper test takes three months. The professional solution is a solicitor-drafted Radon Retention (Bond).
This allows you to complete the sale on time, with a sum of money held to cover any potential remediation costs, ensuring the health risk is assessed after completion without derailing your timeline.
What your Radon Search means: UK Action Level
Your solicitor’s Environmental Search confirms the risk level in the area. This search will state the estimated percentage of properties in your area likely to be above the Action Level, the point at which remedial work is needed.
It is important to understand that Radon Reports flag general areas, but this does not always mean your specific property is affected. The only way to know is through a proper test.
The UK Action Level is 200 Becquerels per cubic metre (Bq m-3). If your long-term test result exceeds this, remediation is needed. The UK target level, which you should aim for, is 100 Bq m-3.
What does it mean if my conveyancing search flags a 'Radon Affected Area'?
It means your property is located in a geographic area where the UK Health Security Agency (UKHSA) estimates that 1% or more of homes contain radon levels above the Action Level.
Crucial Point: The search result flags the area, not the specific property. This does not guarantee your home has high levels, nor does it mean you should withdraw from the purchase.
It simply triggers the need for a definitive 3-month test to confirm the concentration inside your specific building. Radon concentration is highly dependent on the individual property’s construction, ventilation, and geology.
The Radon Retention (Bond)
Since the definitive long-term test takes three months, a Radon Retention is the standard conveyancing mechanism to manage the risk and timeline.
A retention is a sum of money agreed between the buyer and seller and held by one of the solicitors after the sale completes. It covers the potential cost of fixing a radon issue once you have moved in and completed the test.
Detail | The Facts |
|---|---|
Details Why is it needed? | The Facts To prevent the 3-month test time from delaying the entire property purchase. |
Details Retention Amount | The Facts Typically between £1,000 and £3,000 to cover remedial works (costs range from £600 to £2,000). |
Details Process | The Facts The money is held for approx 6 months to cover the 3-month test, lab analysis (approx 4–6 weeks), and receipt of the report. |
Details Outcome | The Facts Low Levels: The full retention is released back to the seller. High Levels: The money is used for necessary remedial work; any surplus is returned to the seller. |
How to conduct the Radon Test
You must arrange a valid test to know your property's actual radon level. The long duration is necessary to average out natural fluctuations caused by factors like weather, air pressure, and ventilation.
Testing options and timeframes
Pro Tip for Buyers: To save time, you can buy a test kit now and ask the seller to place the detectors in the property before you complete. This starts the clock early.
Standard Long-Term
- Timeframe: 3 Months.
- Accuracy: Highest. This is the official measurement (e.g., UKHSA/UKradon.org) required to check against the Action Level.
- Use Case: Required for a definitive result and to determine if remediation is needed.
Short-Term
- Timeframe: Approx. 10 Days.
- Accuracy: Snapshot Result. Not definitive, as it doesn't average out fluctuations.
- Use Case: Indicator Only. Useful for getting an early, quick risk assessment during the sale process.
The Standard 3-Month Test process
- Order: Purchase the Home Measurement Pack (from UKHSA/UKradon.org for approx £53).
- Placement: Place two detectors, one in the living area and one in an occupied bedroom, according to instructions. The property must be occupied on a normal basis.
- Duration: Leave in place for the full 3 months.
- Analysis: Post detectors back to the lab. Analysis typically takes 4–6 weeks.
- Result: If the level is high, the report will advise on the most suitable remedial method.
Guidance for buyers and sellers
For the Buyer (Managing the Risk)
As the buyer, your priority is assessing the risk without accepting delays. You should:
- Ask for Proof: Always ask the seller if a long-term radon test has been done. If a report is provided, your solicitor will review the result against the Action Level.
- The Best Move: If no test exists, proceed with the purchase via a Radon Retention, managed by your solicitor, and arrange the 3-month test immediately after you move in.
- Remedial Costs: If the test comes back high, the retention funds are used to pay for the required remedial works, which typically involve improving ventilation or installing a radon sump.
Property scenarios: new builds and landlords
New build properties
When required by building regulations, new build properties in radon-affected areas are expected to have radon protective measures installed.
- Basic Protection: Protection is provided by a damp-proof membrane modified and extended to form a radon-proof barrier across the ground floor.
- Full Protection: Comprises a radon-proof barrier and provision for subfloor depressurisation (a capped radon sump) or ventilation (a ventilated subfloor void).
Even with these measures, the UKHSA recommends doing a 3-month radon test in your new home during the first year of occupation. If the result is high, the additional measures (like activating the sump with a fan) can be used to reduce levels further.
Buy-to-let properties and upgrades
- Buy-to-Let: Radon is listed as a hazard under the Housing Health and Safety Rating System Regulations. Landlords owning properties in affected areas must have a hazard assessment carried out. Contact your local council for further details.
- Major Works: If you want to upgrade or extend your property significantly, you should seek professional advice from your local council's Building Control or Environmental Health Department, as new regulations may apply to the modified structure.
Andrew started his career in 2000 working within conveyancing solicitor firms and grew hands-on knowledge of a wide variety of conveyancing challenges and solutions. After helping in excess of 50,000 clients in his career, he uses all this experience within his article writing for SAM, mainstream media and his self published book How to Buy a House Without Killing Anyone.
Caragh is an excellent writer and copy editor of books, news articles and editorials. She has written extensively for SAM for a variety of conveyancing, survey, property law and mortgage-related articles.
