Radon Risk Checker
Check radon risk for any UK postcode. See risk level based on UKHSA/PHE National Radon Atlas data 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. DIY detectors from UK Radon (ukradon.com) cost around £30 and are placed for at least 3 months. If levels exceed 200 Bq/m³, remediation is required but 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 classifies postcodes using outcode prefixes matched against known high-risk geological zones from the UKHSA/PHE National Radon Atlas. It's an area-level estimate — actual levels vary property by property, particularly based on floor level and construction type.
- 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.
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