Some of it, yes. About one postcode in ten sits in the highest river or sea flood zone. The rest of the town is on safer ground. There are no recorded historic flood events for Seaford on the national register. Which street you buy on matters far more than the town average.
On the river and sea maps, roughly nine percent of postcodes fall inside the highest-risk zone, the one that indicates a significant annual chance of flooding. Under one percent sit in the middle zone. The rest are outside both. That reflects the town's geography: the built-up part of Seaford sits behind the shingle bar and the beach, with the Ouse valley running to the west and the Cuckmere to the east. The exposed postcodes are concentrated where the low ground meets the seafront and where the river valleys touch the built edge of the town, not distributed evenly across it.
When surface water and other flood sources are added in, the picture broadens. About seven percent of postcodes carry a high overall risk from any flood source, just under one in ten face medium risk, and close to a quarter sit with some low-level risk to weigh. Surface-water flooding is the kind that comes from heavy rainfall rather than rivers or the sea, and it hits streets whose drainage cannot cope with a summer downpour. It does not always show up on the river-and-sea maps, which is what tends to catch newer buyers off guard. In a coastal town built at varying elevations, that risk is uneven street by street.
Recalculated for climate-adjusted sea levels and river flows, the high-risk share rises to about one postcode in nine. The shift on current numbers is modest. The forward warning is that streets which sit marginal now become firmly exposed by mid-century. The sea-level trend measured at the nearest long-record tide gauge, at Portsmouth, is about two millimetres a year, which does not sound like much and adds up to more than most homeowners plan for. The shoreline management policy for this coast is currently to hold the line across the twenty, fifty and hundred-year horizons, meaning the defences will be maintained rather than allowed to retreat, at least on the current published plans.
For insurance, the practical implication is that homes in the higher-risk zones will face higher premiums and, in some cases, restricted cover. Flood Re, the government-backed flood reinsurance scheme, covers most at-risk homes but does not cover homes built since 2009. A property built in the last fifteen years and sitting in a high-risk zone can end up harder to insure than a Victorian house on the same street. Anyone buying near the seafront or in one of the low-lying pockets should get an actual quote before they exchange, not after, and should ask specifically whether Flood Re applies to the property.
The town-wide picture is not alarming, but the postcode-level picture is real. If your address sits inside one of the exposed pockets, treat the risk as a live one. If it does not, the sea is a view rather than a problem.