Radon affected areas, postcode area by postcode area
Across the 411 postcode districts with a guide so far, in 14 postcode areas, parts of the surrounding 1 km square are a radon Affected Area at 1872 of the 3712 postcodes we checked (in B6, B7, B20, B21, B23, B31 and 255 more districts).
The highest band found is up to 30% or more of homes above the action level (in BS13, DE4, DE45, LE14, NG32, S32 and 2 more districts). The map describes each square, not any home: only a three-month test measures a house.
From UK Health Security Agency and British Geological Survey radon map, checked at 7 to 9 postcodes in each district guide, the newest built in October 2026. These are the postcode areas we've built guides for so far, not a map of the whole country. Facts with their sources, not a rating: an area with nothing found isn't safe, and one with findings isn't unsafe. The maps describe the ground, not any home.
Check a postcode
Free, from the UKHSA and British Geological Survey radon map for Great Britain. No account needed.
Postcode area by postcode area
Sampled: the 1 km squares around 7 to 9 postcodes in each district
| Postcode area | Districts with a guide | Postcodes in an Affected Area | Highest band found | Found in |
|---|---|---|---|---|
| B Birmingham | 77 | 153 of 720 postcodes | Up to 10–30% of homes above the action level | B6, B7, B20, B21, B23, B31, B32, B42, B43, B44, B45, B49, B50, B60, B61, B62, B63, B64, B65, B67, B68, B69, B70, B71, B74, B75, B77, B78, B96 |
| BL Bolton | 9 | 65 of 72 postcodes | Up to 10–30% of homes above the action level | BL1, BL2, BL3, BL4, BL5, BL6, BL7, BL8, BL9 |
| BS Bristol | 37 | 304 of 336 postcodes | Up to 30% or more of homes above the action level | BS1, BS3, BS4, BS5, BS6, BS7, BS8, BS9, BS10, BS11, BS13, BS14, BS15, BS16, BS20, BS21, BS22, BS23, BS24, BS25, BS26, BS27, BS28, BS29, BS30, BS31, BS32, BS34, BS35, BS36, BS37, BS39, BS40, BS41, BS48, BS49 |
| DE Derby | 23 | 80 of 196 postcodes | Up to 30% or more of homes above the action level | DE1, DE4, DE5, DE7, DE12, DE21, DE22, DE24, DE45, DE55, DE56, DE65, DE72, DE73, DE74, DE75 |
| LS Leeds | 29 | 247 of 260 postcodes | Up to 5–10% of homes above the action level | LS1, LS2, LS3, LS4, LS5, LS6, LS7, LS8, LS9, LS10, LS11, LS12, LS13, LS14, LS15, LS16, LS17, LS18, LS19, LS20, LS21, LS22, LS23, LS24, LS25, LS26, LS27, LS28, LS29 |
| LE Leicester | 21 | 116 of 208 postcodes | Up to 30% or more of homes above the action level | LE2, LE3, LE5, LE6, LE7, LE8, LE9, LE12, LE13, LE14, LE15, LE17, LE18, LE19, LE65 |
| L Liverpool | 40 | 36 of 364 postcodes | Up to 10–30% of homes above the action level | L12, L24, L25, L27, L34, L35, L36 |
| M Manchester | 42 | 95 of 420 postcodes | Up to 10–30% of homes above the action level | M4, M6, M12, M13, M24, M25, M26, M27, M28, M29, M35, M38, M40, M45, M46 |
| NG Nottingham | 29 | 157 of 264 postcodes | Up to 30% or more of homes above the action level | NG1, NG3, NG4, NG6, NG7, NG8, NG9, NG10, NG11, NG12, NG13, NG14, NG15, NG16, NG17, NG19, NG20, NG23, NG31, NG32, NG33, NG34 |
| OL Oldham | 16 | 120 of 128 postcodes | Up to 10–30% of homes above the action level | OL1, OL2, OL3, OL4, OL5, OL6, OL7, OL8, OL9, OL10, OL11, OL12, OL13, OL14, OL15, OL16 |
| S Sheffield | 45 | 354 of 400 postcodes | Up to 30% or more of homes above the action level | S1, S2, S3, S4, S5, S6, S7, S8, S9, S10, S11, S12, S13, S14, S17, S18, S20, S21, S25, S26, S32, S33, S36, S40, S41, S42, S43, S44, S45, S60, S61, S62, S63, S64, S65, S66, S70, S71, S72, S73, S74, S75, S80, S81 |
| SK Stockport | 19 | 63 of 152 postcodes | Up to 30% or more of homes above the action level | SK4, SK6, SK11, SK14, SK15, SK16, SK17, SK22, SK23 |
| WA Warrington | 16 | 41 of 128 postcodes | Up to 10–30% of homes above the action level | WA5, WA6, WA7, WA8, WA9, WA10, WA11 |
| WN Wigan | 8 | 41 of 64 postcodes | Up to 10–30% of homes above the action level | WN1, WN3, WN4, WN5, WN6, WN7, WN8 |
Each district guide checks 7 to 9 postcodes spread across the district, so "5 of 61 postcodes" means five of those centres, not a share of homes. Open a district for its own guide, with every postcode listed.
Radon town by town
The same check, district by district, for the towns with enough guides:
What it means when you buy
It depends on the rocks and soil. The radon map gives each 1 km square the share of homes estimated to be above the action level:
- Below 1%: the square isn’t a radon Affected Area.
- 1% or more: it’s a radon Affected Area, and a test is recommended.
- The map describes the area, not the house: only a test measures a particular home.
- Raised radon can usually be reduced, for example with a radon sump.
Raised radon is common in some parts of the country and rare in others. Knowing the area’s potential tells you whether to ask about testing and protection before you commit.
A higher-radon area isn’t a reason on its own to walk away. Raised levels in a home can usually be reduced, for example with a radon sump, and a specialist can quote for it.
Questions to ask about a home
- Has the house been tested for radon, and what was the result?
- Was radon protection fitted when it was built or since?
- If levels were raised, what was done, and was it tested again afterwards?
The full report checks the house itself, not the postcode, and ties each question to what it found. See an example report.