Radon Risk Checker
Check radon potential for any postcode in Great Britain. See risk level from the UKHSA/BGS radon atlas and find out if testing is recommended.
Radon and property purchases in the UK
Radon is a naturally occurring radioactive gas produced by the decay of uranium in rocks and soils. It seeps through the ground and can accumulate in buildings, particularly at lower levels. Long-term exposure to elevated radon is the second leading cause of lung cancer in the UK after smoking, responsible for around 1,000 deaths per year.
High-risk areas include Cornwall, Devon, parts of Derbyshire and Northamptonshire, and areas of Scotland with granitic geology. The UKHSA (formerly PHE) publishes a National Radon Atlas showing affected areas.
If you are buying in a high-risk area, a radon measurement test is strongly recommended. A home test from UKHSA (ukradon.org) costs £52.80 including VAT and runs for three months. If a home measures above 200 Bq/m³, UKHSA recommends reducing it, which is typically straightforward and cost-effective.
Frequently asked questions
What is the UK action level for radon?
The UK action level is 200 becquerels per cubic metre (Bq/m³). If a home measures above this, the UKHSA recommends remediation. The target level for remediated buildings is below 100 Bq/m³. For context, most UK homes measure around 20 Bq/m³.
How is radon risk assessed by postcode?
This tool reads the Indicative Atlas of Radon in Great Britain (UKHSA and the British Geological Survey) at the postcode centre. Each 1 km square is classed by the highest radon potential anywhere inside it, from under 1% to over 30% of homes above the Action Level. It describes the square, not one home: actual levels vary property by property, particularly with floor level and construction. Northern Ireland has its own UKHSA map.
Does radon risk affect property value or mortgages?
Radon itself doesn't typically prevent mortgages or significantly affect valuations — surveyors rarely note it unless very high levels are already known. However, if a test reveals very high levels, remediation would normally be required or negotiated before exchange.
How much does radon remediation cost?
Simple measures like improved underfloor ventilation or sealing entry points can cost as little as a few hundred pounds. A positive pressurisation unit (the most common solution) typically costs £500–£1,500 installed. In severe cases, a sump system may cost £1,500–£2,500.
Radon is just one environmental risk
Look up a specific home by its address for AI-powered insights on radon, flood risk, mining, and more.
A screening indication from public data, not a survey or a site investigation. It does not replace a specialist report, and the absence of a flag is not evidence of the absence of risk.
Contains public sector information licensed under the Open Government Licence v3.0.
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