About radon.tips

What is radon.tips?

radon.tips is an independent tool for looking up radon gas risk by postcode district across England. We publish risk data for over 2,300 postcode districts, sourced entirely from publicly available government data.

We have no commercial affiliation with any radon testing company, mitigation contractor, or insurer. Links to testing services are provided as a convenience and are independently chosen based on their accreditation status.

Data sources

• BGS Radon Indicative Atlas v3 — Produced by the British Geological Survey (BGS). The atlas maps radon potential across Great Britain on a 1km grid, expressed as the percentage of homes expected to exceed the UK Action Level of 200 Bq/m³. Licensed under the Open Government Licence v3.0.
• ONS National Statistics Postcode Lookup (NSPL) February 2026 — Produced by the Office for National Statistics (ONS). Used to map postcode districts to BGS grid squares and county boundaries. Licensed under the Open Government Licence v3.0.

How risk levels are calculated

Each postcode district is assigned a radon risk class (1–6) by finding the modal BGS class across all postcodes within the district. The modal (most common) class is used rather than the maximum, to give a representative figure for the district as a whole.

For a detailed explanation, see our methodology page.

Limitations

• Radon levels vary significantly even within small areas. A district-level risk rating is a guide, not a measurement of your specific home.
• The only reliable way to know your home's radon level is to conduct a radon test.
• The BGS Indicative Atlas is based on geological mapping and measured radon data. It is updated periodically — check BGS.ac.uk for the latest version.
• London and metropolitan areas have reduced county-level data due to unitary authority boundaries in the NSPL.

Contact

For data queries or corrections, you can reach us via the BGS data feedback mechanism at bgs.ac.uk. For site-specific queries, raise an issue on GitHub.