Radon Levels by Postcode — Is Your Area Radon Affected?
Check any UK postcode against UK Health Security Agency (UKHSA) indicative radon data. Radon is a radioactive gas that causes over 1,000 lung cancer deaths per year in the UK, and approximately 2 million homes are in radon-affected areas. This is a postcode-area reading: it shows your area's radon Affected Area class — the estimated percentage of homes at or above the Action Level — not the radon level inside any specific house, which only a measurement can give. The £24.99 Complete report includes the radon area class for a specific address with remediation guidance.
This check runs on screen, no signup. The full property report is £9.99 Lite / £24.99 Complete — one report, one price, no subscription.
Frequently asked questions
Radon is a naturally occurring radioactive gas produced by the decay of uranium in rocks and soil. It's colourless and odourless. The UK Health Security Agency states that radon causes over 1,000 lung cancer deaths per year in the UK. The Action Level is 200 Bq/m³ — above this, remediation is recommended.
The highest radon levels in England and Wales are found in Cornwall, Devon, Somerset, Northamptonshire, and parts of Derbyshire and the Peak District. However, radon can vary significantly even within a postcode. HouseCheckup uses UKHSA indicative data to show the estimated percentage of homes above the Action Level in your area.
Mortgage lenders may require a radon survey for properties in high-risk areas. Remediation (typically a radon sump system) costs £800–1,500. HouseCheckup flags radon risk in the IQ Score and Complete report so you can factor this into your offer and budget.
The UK Action Level is 200 becquerels per cubic metre (Bq/m³) — above this, UKHSA recommends taking action to reduce radon. The Target Level is 100 Bq/m³, the level below which the risk is low and which you should aim for after any remediation. Levels are measured as an annual average, because radon fluctuates day to day and seasonally (it's typically higher in winter), which is why a proper test runs over about three months rather than a single spot reading.
If the property is in a radon Affected Area — where the indicative map shows a meaningful percentage of homes above the Action Level — then yes, a radon test is strongly advised, and it's cheap relative to the risk. A radon test isn't a standard part of conveyancing, so it's on you to ask. The area class gives you the probability; only a test in the actual building, ideally over three months, confirms the level you'd be living with. If you can't test before completion, you can test afterwards and remediate if needed.
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