Radon
You will use the basement as a room and the only radon information is an area map. Why is the map not a reading in that room?
The map is not a reading in that room. An area map describes radon likelihood across ground, not the air in the basement you will use. Using the space as a room does not sample it. The survey has not measured radon there, and it has not turned a published map into a detector result. Until a proper test is done in the house, the room itself is unmeasured. The basement air remains unknown.
Last reviewed 24 October 2026. Written for buyers in England and Wales unless this answer says otherwise. No named surveyor has signed this page. It is general guidance, not a report on your house, and not legal advice.
What is the fuller explanation?
UKradon maps are a way of seeing whether a district is one where testing is worth considering. They are not a measurement of a named basement. A room below ground sits closer to the soil, which is why the question comes up, but closeness is not a reading and a plan to sleep or work there does not create one. The home survey did not place detectors and did not report a level. The map can stay in the pack as a map.
If you will use the basement, arrange a radon test in that room rather than resting on the area map. Tell the solicitor the survey has not measured the air. Do not tell a lender the basement has a radon result when the only paper is a map. Any later test is a different product from this home survey, and the map remains what it was.
What should you ask your surveyor?
- Is the only radon information an area map, with no reading in the basement?
- Has the survey left the air in that room unmeasured?
- Are you keeping the map separate from a test of the room you will use?
What are the typical next steps?
- Do not treat the area map as a reading in the basement.
- Arrange a radon test in the room if you will occupy it.
- Tell the solicitor the survey did not measure the air.
Costs vary with the building and with who you instruct. Where this page does not cite a published figure, ask the surveyor, a relevant specialist, or your solicitor for a written quote. Do not treat a forum average as the price.
Also asked about this
If the map colour looks low, is the basement cleared?
No. A colour on an area map is still a map. It is not a reading in the room you will use. The survey has not measured that air, and a reassuring district does not sample the basement. Colour is not a detector.
Does airing the basement replace a test?
No. Opening a window changes the air for a while. It is not a measurement, and it does not turn the area map into a result for that room. The survey still has not measured radon in the basement. Ventilation is not a result.