Survey finding
Radon mitigation: what UK buyers should check
Radon-affected areas cover meaningful parts of the UK. This page covers UKHSA mapping, the Action Level, and what mitigation costs.
Last updated: .
Finding
Radon: mitigation required
What this usually means
Radon is a naturally occurring radioactive gas formed by the decay of uranium in some rocks and soils. UKHSA (formerly Public Health England) maps radon-affected areas; certain regions (parts of the South West, Pennines, Northamptonshire) have a higher proportion of homes above the 200 Bq/m³ Action Level. Mitigation involves a sealed barrier under a new build, or a radon sump and fan retrofitted into an existing property.
Why it matters
Above the Action Level. Radon is a recognised long-term lung cancer risk and mitigation is recommended. Lenders rarely refuse on radon alone but may want documented mitigation in high-affected areas. The conveyancer's environmental search flags radon risk; a 3-month test confirms actual levels at the address.
Ask your surveyor
- Check:Is the property in a designated radon-affected area?
- Check:Are there visible signs of radon mitigation (sump, fan)?
Ask the seller
- Check:Has a radon test been carried out, and what was the result?
- Check:Is there any radon mitigation installed?
Next steps
- •Get two written quotes from local trades before negotiating with the seller.
- •Speak to your mortgage broker before exchanging if the finding affects mortgageability.
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What you need to know
Severity
Significant. Specialist follow-up usually warranted before exchange.
Typical cost to fix
3-month radon test kit: £40–£60 from UKRadon. Radon sump and fan installation: £1,000–£3,500. Membrane retrofit (more disruptive): £3,000–£8,000. New-build radon barrier: included in build cost in affected areas.
Mortgage impact
Standard for most lenders. Significant elevations with no documented mitigation may trigger a condition.
Insurance impact
Not directly insured. Health risk is the buyer's consideration.
When to pull out
Almost never. Pull out only if radon levels are very high, mitigation cost is unviable, and the seller refuses.
When to renegotiate, and by how much
If mitigation is recommended, get a quote (£1,000–£3,500). Negotiate full quote off the price or ask the seller to install before completion.
Thinking of pulling out or renegotiating? What to do after a bad survey
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The Survey Decoder explains the wording. The full report adds address-specific flood, subsidence, EPC, crime, listed status, building age and price comparison data, so a single finding isn't judged in isolation.
Run the check
Check the property before you offer
Free preview: flood risk, EPC rating, crime, tenure and air quality. The £9.99 report adds the remaining 17 checks, 22 in all, drawing on up to 15 public datasets.
Run a free previewRead next
Radon affected area , often sits near radon: mitigation required on a survey and is the next thing to check.
Radon risk when buying a house , the full buyer guide behind this finding rather than the one line a surveyor writes about it.
House survey cost UK , what a Level 2 and a Level 3 actually cost in 2026, and Level 2 vs Level 3 , what each level does and does not cover. Not every finding here is something a surveyor assesses — some are a conveyancer's search — and the comparison says which is which.
How MyPropertyScan produces this guide, and what it is not
Published by MyPropertyScan and written by Ziad Nasr, who is accountable for its accuracy. No page here is written or reviewed by a chartered surveyor, conveyancer or regulated adviser, and we do not claim otherwise.
This page is not:
- Chartered surveying: we do not inspect properties or produce RICS Home Survey reports
- Legal advice: we do not act as conveyancers or advise on title, tenure or contracts
- Mortgage or insurance advice: we are not regulated by the FCA and give no recommendations
Figures and process steps come from the published UK datasets and standards listed on this page, not from professional practice. Pages are updated when source coverage, survey cost assumptions, or lender and legal requirements materially change. Dataset limitations are set out on the methodology page.
Spotted something out of date or wrong? Email [email protected] and we will correct it and change the update date.
Sources used
We use UK public and specialist sources where they are available. Public datasets can be incomplete, delayed, or missing for some addresses. Treat them as a starting point, not as a replacement for professional advice.
Source standard: preference goes to official government datasets, statutory bodies, professional standards, and primary dataset publishers. We cite the source family on the page and explain coverage limits rather than filling gaps with unsupported estimates.
- Professional standard: RICS Home Survey StandardRICS standard for condition-based residential surveys in the UK.
- Learn more from: RICS consumer guide to surveysConsumer-facing guide to survey types and when each level is appropriate.
- Official guidance: GOV.UK buying or selling your homeGovernment overview of the home buying and selling process.