From rivers and the sea, hardly at all. Once rain is counted too, the risk is real. Almost no postcodes sit in a river flood zone. None sit in the highest one. About one in five still rates high on at least one flood measure. The river maps look clean, but the other flood maps do not.
The Environment Agency's river-and-sea flood zones barely reach Tenterden. About 1% of the area's postcodes sit in flood zone 2, the medium-probability band, and none sit in flood zone 3, the high-probability band. The two zones don't overlap, since zone 2 is the fringe beyond zone 3. Here the fringe is thin and there is nothing inside it. The town sits on the edge of the Weald above the Rother valley, which is where anyone with sense would have built it.
Surface water is the risk those zone maps leave out. It comes from heavy rain that the ground and the drains can't absorb, and it can hit streets a long way from any river. Tenterden has no surface-water-only figure of its own. Surface water is folded into the broader postcode measures further down this page, and that is where this town's risk actually shows up. Nobody will mention it on a viewing, because the river zone check comes back clear and everybody stops looking.
For the future, the Environment Agency's climate-adjusted flood zone covers about 1% of postcodes, the same as the zone 2 figure today. That allowance deals with river and sea flooding only, and on that measure Tenterden stays on the dry side.
Insurers price the address, not the town. A postcode that rates high for surface water can cost more to cover or come with a bigger excess, even when the river maps are clean. Get an indicative quote on the exact house before you instruct a solicitor, not after you exchange.
The postcode indicators combine every source. About 19% of postcodes rate high on at least one flood measure, about 15% medium on at least one, and about 34% low on at least one. The bands overlap because each postcode is judged on its worst measure. Do not add them to the zone shares above: they are a different measure, and they are the reason Tenterden's flood picture is not as clean as the river maps suggest.
Counted as properties, the Environment Agency's rivers-and-sea register lists 4 postcodes carrying some risk, covering 49 properties. Of those, 3 are at high risk, 3 at medium and 15 at low. Only one of the high-risk properties is a home. Only postcodes with some river or sea risk are listed at all, and everything else in the town is absent because the rivers don't reach it.
On whether anything stands between the water and the house, the Environment Agency's modelled extents put no postcodes in the high-risk river-and-sea extent at all, defended or not. About 1% sit in the low-risk undefended extent. Where a defence does appear in that modelling, it only means the defence is present. It does not make the property safe, and nothing in these figures should be read as reassurance.
The nearest tide gauge, at Dover, recorded sea level rising by about 2 millimetres a year over its record from 1961 to 2010. That is a measured past rate on the coast, not a forecast for an inland town sitting above the Rother.
There is no recorded historic flooding in the area. That counts for something, but it doesn't prove water has never come through a front door. It only means nobody put a flood on the official record.
Tenterden's flood risk is below average, and all of that comes from rain rather than rivers. A buyer who stops at the river zone map will be reassured by the wrong measure.