Yes, and for more of Byfleet than a dry afternoon would suggest. About a quarter of its postcodes have flooded before. Over a third fall inside the flood zone once climate change is allowed for. More than a hundred properties face a high chance of river flooding. The Wey Navigation looks like scenery, and it is also the village's drainage.
The Environment Agency's river-and-sea mapping puts about 6% of Byfleet's postcodes in Flood Zone 3, the highest-probability band. Another 28% are in Flood Zone 2, the medium-probability band that runs beyond it. The two bands do not overlap, so a Zone 2 postcode is the next ring out from Zone 3 and is in no sense a share of it. Most of Byfleet's river exposure is the medium kind, which is the kind people talk themselves out of.
Byfleet has no standalone surface-water figure on this page, and rain flooding is counted in the postcode measure below. The history is clear enough. About 26% of postcodes fall inside the Environment Agency's outlines of past floods, from 133 recorded events. The most recent on that record was in December 1990, when the main river overflowed its channel at a point with no raised defences. Thirty-odd dry years count as a gap in the record. They do not mean the river has moved.
Once the Environment Agency adds its allowance for climate change, the share of postcodes inside the flood zones grows to about 39%. That is the agency's modelled view of where the zones would reach under a wetter future, and it is the line a lender's surveyor may be reading in twenty years.
Insurance is where this turns into money. A home in Zone 3, or one with a flood claim in its past, can mean higher premiums, a higher excess or fewer insurers willing to quote. A home in Zone 2 usually costs less to cover, though each insurer prices it differently. The seller's answer on the property information form about past flooding and claims is the most useful paragraph in the whole conveyancing bundle, so read it as closely as the price.
Taken postcode by postcode, about 9% of Byfleet rates high risk on at least one flood measure, about 16% medium and about 42% low. Those bands include surface water alongside rivers and sea, and they overlap with the flood-zone figures above, so the two sets should never be added together. "Low" in these bands still means somebody modelled water reaching the postcode.
Counted in homes, the Environment Agency's rivers-and-sea mapping lists 2,682 properties in the 137 postcodes that carry any risk at all. Postcodes with no risk are left out entirely. Of those listed, 119 properties are at high risk, 96 of them homes, 275 at medium risk and 1,861 at low risk. Six are rated very low. The 96 homes at high risk are a short enough list that their owners probably know who they are.
On whether anything stands in the water's way, about 6% of postcodes fall inside the high-risk extent with no defence in the model, against about 5% where a defence is modelled. "Defended" here only means the Environment Agency's model includes a wall or bank somewhere along the river. It makes no promise about how that defence performs, and in Byfleet the undefended share is the bigger of the two.
The nearest tide gauge, at Portsmouth, recorded sea level rising about 2 millimetres a year between 1962 and 2023. That is the rate measured on the coast over those years. Byfleet's water arrives by the Wey, not the sea, so the gauge matters less here than the river does.
Flood risk is Byfleet's weak spot, and most of the village is still dry ground. The postcode decides which side of that line a house is on, and the river has the deciding vote.