Yes, though mostly from rain. River flooding touches only a sliver of the town. About one postcode in six rates high on at least one flood measure once surface water is counted. No flooding is on the record. Ewell's flood risk falls out of the sky and spreads through the streets, and very little of it comes over a riverbank.
The Environment Agency puts about half of one per cent of Ewell's postcodes in flood zone 3, the highest-probability band for flooding from rivers and the sea, and just under 1% in flood zone 2. Zone 2 is the medium-probability fringe beyond zone 3, so the two shares are separate slices and should be read alongside each other. Both are small, and they cover river and sea flooding only.
Surface water is the bigger concern. Ewell grew up along the spring line where the chalk of the North Downs meets the London clay, and its name comes from the Old English for a spring. When heavy rain falls on clay, it pools in dips and low roads and has nowhere quick to drain. The postcode figures further down count that kind of flooding alongside the rivers, which is why they come out much higher than the zone shares. The town is named after its water, and that water mostly comes up out of the ground.
Under the Environment Agency's climate-change allowance, the share of postcodes in the river-and-sea zones grows to about 2%. That is a modelled future extent, and it still covers a small part of the town.
Insurers price each address on its own mapping, and surface-water risk counts with them even where the river zones are clear. Get a buildings insurance quote on the exact address early on, because a high surface-water rating can lift the premium or the excess well before a solicitor finds anything to raise.
Counting every measure together, including surface water, about 16% of Ewell's postcodes rate high on at least one flood measure, 20% rate medium and 38% rate low. These bands overlap with the zone figures and are a wider net, so they should never be added to them. They do explain why two houses on the same road can come back with different results.
The Environment Agency's rivers-and-sea mapping lists 879 properties across the 34 Ewell postcodes that carry any river or sea risk. Postcodes with no risk at all are left out of that list. Of those properties, 46 are at high risk, 23 at medium and 179 at low, and 45 of the high-risk ones are homes. As a count of actual houses, river flooding is a problem for a few dozen households.
In the Environment Agency's high-risk modelling, about half of one per cent of postcodes fall inside the undefended flood extent, and about the same share fall inside the extent where a defence is present. A defence in the model means something is shown standing between the water and the house. It says nothing about how well that defence will hold, so it should not be read as a promise that the house stays dry.
The nearest tide gauge, at Portsmouth, recorded sea level rising by about 2 millimetres a year between 1962 and 2023. That is a past rate at a harbour a long way south, and it matters to Ewell mostly as a sign of where the climate is heading.
No flooding is recorded in Ewell's historic flood outlines. That is reassuring, though records only hold the floods somebody mapped, and surface-water floods are the least likely to be mapped.
Flood risk is one of Ewell's weaker points, below average because surface water reaches far more streets than the rivers do. Few homes face a real threat from a river, and the rain is the thing to check at each address.