For most homes, no, but for a real minority, yes. About one postcode in five rates high risk on at least one flood measure. The river flood zones cover only a thin slice of the village. Rain with nowhere to go counts too. Check the address, not the village.
The Environment Agency's river-and-sea flood zones cover a small part of East Horsley. About 6% of the area's postcodes sit in flood zone 3, the highest-probability band, and a further 3% sit in flood zone 2, the medium-probability fringe beyond it. The two bands don't overlap, so the second figure being smaller is expected. East Horsley is inland, so for this village "river and sea" mostly means river.
Surface water, the flooding that comes from heavy rain overwhelming drains and low ground rather than from a river bursting its banks, has no separate share for East Horsley. It's counted inside the postcode-level measure further down, which is why that measure runs higher than the flood-zone figures. It's the kind of flooding that doesn't care how far you are from a river, and it's the one buyers most often forget to ask about.
Looking ahead, about 10% of the area falls inside the Environment Agency's climate-adjusted flood zone, the extent modelled to allow for wetter conditions to come. That's the flood map a thirty-year mortgage will actually live alongside.
Insurance follows the address. A house in one of the higher-risk postcodes can expect an insurer to ask more questions, apply a higher premium or add a larger flood excess than a house a few streets away. Get an indicative buildings-insurance quote for the exact property before you pay for surveys and solicitors, not after. A listing that says "no flood history" describes the paperwork, not the drains.
At postcode level, and counting surface water alongside rivers and sea, about 20% of East Horsley's postcodes rate high risk on at least one measure, about 14% rate medium and about 36% rate low. Because a postcode only needs one measure to qualify, these bands overlap with the flood-zone shares above. Don't add the two sets together or treat them as the same thing.
Counting homes rather than postcodes gives a sharper answer. The Environment Agency's rivers-and-sea mapping lists 652 properties in the postcodes carrying some risk: 140 at high risk, 96 at medium and 81 at low. Of the high-risk properties, 121 are homes. Postcodes carrying no risk don't appear in this count at all, so the total covers the exposed part of the village, not all of it.
On whether anything stands between the water and the house, the modelling doesn't help much. About 7% of postcodes fall inside the high-risk flood extent with defences left out of the model, and about 7% fall inside it with defences included. "Defended" only means a defence appears in the model. It doesn't mean a property is safe, and here the modelled defences barely move the high-risk extent at all.
The nearest tide gauge is at Portsmouth, where the record from 1962 to 2023 shows sea level rising at about 2 millimetres a year. That's a measured historic rate at the coast, not a forecast, and for an inland village it matters mainly for the wider region.
No recorded historic flooding is logged for the area. That's reassuring, but a clean record means no flood made it into the official files, not proof the ground has always stayed dry.
Flood risk is one of East Horsley's weaker points. Most of the village is clear, but the minority of homes in the high-risk postcodes carry it properly, and a buyer should treat the individual address as the whole answer.