Yes, and more than most places with a High Street and a cricket green. Around half the area falls inside a recorded flood outline. One postcode in five carries a high risk on at least one measure. Hundreds of homes are mapped at high risk from the river. The Thames is the reason to live here and the main thing to check.
The Environment Agency splits river and sea risk into flood zones, and the two are separate bands. In Thames Ditton, 14% of postcodes are in zone 3, the highest-probability band, and a further 32% are in zone 2, the medium-probability fringe beyond it. The village started out isolated on marshy wetland beside the river, so the map is reporting something the ground has always known. It also has an inhabited island in the Thames, which tells you how relaxed people here have long been about water.
The river is only one source. The Environment Agency holds 139 recorded flood events for the area, and 51% of it falls inside a historic flood outline. The most recent recorded event was in January 2003, when an ordinary watercourse overtopped its channel with no raised defences in the way. That's a smaller stream doing the damage, the kind of water nobody puts in a photograph of the view.
Looking ahead, the Environment Agency's climate-adjusted flood zone covers about 43% of the area, a modelled picture of where the zones would reach under its climate allowances.
For insurance, a home in zone 3 or with a flood history will draw closer questions, a higher premium or a larger excess, and some insurers may decline it. Put the exact address into the Environment Agency's long-term flood-risk service and get a written insurance quote while the survey is being arranged, because the quote is the number that turns up every year. "Riverside" earns its place in the particulars on looks alone, and an underwriter reads the same word as a question.
Counting surface water alongside river and sea, about 20% of postcodes are rated high on at least one flood measure, 23% medium and 58% low. These bands overlap with the zone figures above, so the two sets should never be added together.
Counted in homes and other buildings, the Environment Agency's river-and-sea mapping lists 2,949 properties across the postcodes that carry any risk at all. Of those, 403 are at high risk, 369 of them residential, 257 at medium risk, 1,402 at low risk and 11 at very low risk. Postcodes with no risk don't appear in that count, so it is a tally of the exposed streets.
Defences complicate the map without settling it. About 20% of postcodes sit within the high-risk extent where no defence appears in the Environment Agency's model, and about 22% within it where a defence is present. A defence in the model means a structure exists and was accounted for. It says nothing about whether a particular house stays dry when that structure is overtopped or fails.
The nearest tide gauge with a long record is at Portsmouth, where sea level rose by about 2 millimetres a year between 1962 and 2023. That's the rate measured on the coast over those years, and it's the background to every flood conversation along the Thames.
Flood risk is Thames Ditton's weakest point by a distance, and it needs checking house by house, from the map to the insurance quote.