Welham Green has a real flood risk, and it comes from the sky. Rivers and the sea barely reach the village. Even so, about one postcode in five rates high on at least one flood measure. Nothing has flooded on record. The river maps clear the village, and the rain maps are a different story.
In the Environment Agency's river-and-sea flood zones, about 1% of Welham Green's postcodes fall in zone 2 and none fall in zone 3. The two zones are separate bands: zone 3 is the higher-probability land nearest the water, and zone 2 is the medium-probability fringe beyond it. In Welham Green the higher band is empty and the fringe is a sliver.
Surface water is where the risk is. When heavy rain falls faster than the ground and the drains can take it, water collects on roads and in low-lying gardens, whether or not there's a river nearby. In a village with no flood zone 3 to speak of, rain accounts for most of what turns up on the flood maps. The Environment Agency maps surface-water risk separately from rivers and the sea, so look up the exact house on that map. The river map has very little to say about Welham Green.
Once the Environment Agency adds its allowance for a changing climate, about 1% of the village's postcodes are inside the flood zone. That leaves the river-and-sea picture much as it is now.
Insurers price on the risk at a particular house, and surface-water risk varies from one end of a close to the other. A home on a high-risk postcode can cost more to insure or come with tighter terms than a neighbour that sits a little higher, even though both are well clear of any river. Ask for an insurance quote early and give the full address.
On the postcode indicators, which count a postcode if any one of several flood measures puts it at that level, surface water included, about 22% of Welham Green's postcodes rate high, about 25% medium and about 39% low. Because these indicators include rainfall flooding, they run far higher than the river-and-sea zones. That gap is the whole story here.
The Environment Agency's rivers-and-sea mapping counts properties as well as postcodes, but only on postcodes with some risk, and just two of Welham Green's postcodes appear. Between them they hold 22 properties: 3 at high risk, none at medium and 3 at low. None of the 3 high-risk properties is a home.
On the same modelling, no postcode falls inside the high-risk flood extent, whether a defence is in the model or not, and about 1% falls inside the low-risk extent with no defence modelled. The defended-or-undefended question barely comes up, because the river water is modelled as stopping short of the village. Even where a defence does appear in that model, it only means something is there. It says nothing about whether the defence will hold.
The nearest tide gauge to Welham Green is at Portsmouth, where the sea rose by about 2 millimetres a year between 1962 and 2023. That is the rate measured on the south coast over those years, and it shows how far this village is from the sea.
There is no recorded history of flooding anywhere in Welham Green. That is reassuring, though small surface-water floods are the kind that often go unrecorded.
Welham Green's flood risk is below par. The rivers stay well away, but the rain finds enough of the village that a buyer needs to check the exact house.