The free flood risk check
most buyers do wrong

Published 28 September 2026  ·  A RISE guide  ·  6–8 minute read  ·  Updated 1 October 2026

The government runs a free, official tool at check-long-term-flood-risk.service.gov.uk that shows flood risk by area for England. It's a genuinely good first step, and it's free. Start with the free tool. A paid property-level report can add detail, but check what it shows that the free tool does not before you buy one. But its own guidance is explicit about what it actually measures: it tells you the flood risk of an area, not a specific property within it. Two homes on the same street can sit at meaningfully different risk depending on their exact elevation, their distance from a specific watercourse or drain, and their individual drainage — detail an area-level tool was never built to capture.

The gap that matters most: groundwater

As we've covered in our separate guide to groundwater flooding, this specific flood type — water rising from saturated ground rather than arriving from a river, the sea, or an overwhelmed drain — is assessed differently to other flood risks. The government tool covers groundwater only where data exists, so a clean result is weak evidence. Ask the seller and the surveyor directly. If you're buying in Chalk geology areas like the Chilterns or the wider Thames Valley, a clean result on a standard flood risk tool tells you comparatively little about groundwater risk specifically, and it's worth asking about directly rather than assuming it's covered.

A practical checklist before you commit

• Run the free government flood risk checker for the postcode — it's the right starting point, not the finishing line.
• Ask the seller directly, in writing, via the TA6 form (see our guide to selling and buying a flooded home) whether the specific property has ever flooded, and of what type.
• Ask specifically about groundwater risk if the property sits on Chalk or river-terrace gravel geology — don't assume a clean surface water or river result covers it.
• Get a buildings insurance quote in principle before you're contractually committed. Difficulty or unusually high cost getting a quote is itself a meaningful, independent signal about real risk that a map alone won't show you.
• Ask your local council or a search agent whether a Section 19 investigation has ever been triggered for the immediate area — a published report, where one exists, is a far more specific and honest account of an area's real flood history than any generic risk map.

If you're weighing up buying a property with genuine, documented flood history and want an independent read on what a council's own records actually show — separate from anything a seller or estate agent tells you — the RISE Section 19 Case Assessment is £250, delivered to your inbox.

Sources: GOV.UK, "Check long term flood risk" service (check-long-term-flood-risk.service.gov.uk, 2026).