Sandy does have a real flood risk, and most of it shows up on the measures that count rainwater as well as the river. Hardly any of the town falls in the official river-and-sea flood zones. About a fifth of postcodes rate high on at least one flood measure. The River Ivel runs through the middle of town. People have run a water mill on the Ivel here since Norman times, so the town has long known where the water goes.
On the Environment Agency's river-and-sea flood zones, about 3% of Sandy's postcodes are in zone 2 and none are in zone 3. The two zones don't overlap. Zone 3 is the higher-probability band, and zone 2 is the medium-probability fringe outside it, so an empty zone 3 alongside a small zone 2 is a consistent picture. Parts of the town and the land around it are still designated a Flood Warning Area.
Surface water from heavy rain is the risk these zones leave out, and Sandy has no separate surface-water share of its own. It is counted in the postcode-level figures further down. About 2% of the area has a record of historic flooding, and 11 flood events are on record, the most recent in 1987, with no source or cause recorded.
The Environment Agency's climate-adjusted zone takes in about 6% of Sandy's postcodes. That is a model of how the zone grows as the climate changes, and it gives no date for any flood.
Insurers price individual properties, and they look at the same mapping. A house in one of the higher-risk postcodes can expect more questions and, quite possibly, a higher premium than the same house on drier ground in the same town. Getting an indicative quote for the exact property early, while the survey is still being booked, costs nothing and settles more than the brochure does.
Count every measure, surface water included, and about 19% of Sandy's postcodes rate high on at least one of them, 24% medium and 49% low. These are shares of postcodes where any one of several flood measures crosses the line, so they are bound to be larger than the river-and-sea zone shares above.
The Environment Agency's rivers-and-sea mapping counts homes and buildings directly. Across the 20 Sandy postcodes that carry some risk, it lists 493 properties, of which 92 are at high risk, none at medium and 199 at low. Of those 92, 46 are homes. Postcodes with no rivers-and-sea risk are left off the list altogether, so those 493 are the properties the mapping has flagged, not the whole town. For a buyer, 92 is a small and specific number, and the only question that matters is whether the house on the viewing list is one of them.
On the Environment Agency's flood-extent modelling, none of Sandy's 254 postcodes falls inside the high-probability extent, with or without defences counted. Because both figures are zero, defences make no difference to the picture here. Where a defence does appear in that model, it only means a defence is there. It is no promise about any particular house.
The nearest tide gauge is at Portsmouth, which recorded sea level rising about 2 millimetres a year between 1962 and 2023. That is the rate measured at that gauge over those years, and the distance between Portsmouth and an inland Bedfordshire town shows how little the sea has to do with Sandy's flooding.
Flood is where Sandy asks the most of a buyer. The river zones look mild, but the wider measures and the 92 high-risk properties mean every purchase here needs its own check.