Radon potential
A natural radioactive gas that seeps from the ground and varies with geology. Potential is banded 1 (lowest) to 6 (highest) — and most of England sits in the lowest bands.
Radon is a colourless, odourless radioactive gas produced naturally by the breakdown of uranium in rocks and soils. It disperses harmlessly outdoors but can accumulate indoors, and because it varies with the underlying geology, some areas have higher potential than others. It is worth understanding, but for most homes it is a low concern.
Radon potential is mapped by the UK Health Security Agency (UKHSA) and the British Geological Survey, banded from Class 1 (lowest) to Class 6 (highest). The band estimates the proportion of homes in an area likely to be above the radon Action Level.
What the bands mean
In Class 1, the lowest band, fewer than 1% of homes are estimated to be above the Action Level; the area is not a radon Affected Area, protective measures are not indicated, and UKHSA advises that measurement is not necessary. As the class rises, the proportion of homes above the Action Level increases, and in higher bands new buildings and extensions may need radon protective measures (a membrane and, in some cases, a sump).
How we report it
We report the radon potential class at your address and what it implies — whether the site is in a radon Affected Area, whether protective measures would be expected for new work, and whether measurement is advised. The report includes a radon potential figure for the surrounding area.
What it means for you
If you are buying in a low band, radon can usually be set aside. In a higher band, a cheap radon test kit (a few weeks of passive monitoring) gives a definitive answer for the specific home, and simple measures — improved under-floor ventilation or a sump — reduce levels effectively where needed. If you are building or extending in a higher band, factor radon protection into the design. A definitive per-property radon report is available from UKradon.org.
Know the risks before you commit
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