Feltham has no river problem, but heavy rain is another matter. None of it falls in the river-and-sea flood zones. About one postcode in seven is at high risk on at least one measure anyway. No flooding is on record. The water that worries Feltham comes down from the sky, and it doesn't need a river to get in.
On the Environment Agency's river-and-sea mapping, 0% of Feltham's postcodes fall in flood zone 3, the highest-probability band, and 0% fall in zone 2, the medium-probability band beyond it. The agency's property-level count of risk from rivers and the sea lists only 3 postcodes, covering 144 properties. Of those, 16 are rated very low risk and none is rated low, medium or high. On rivers and the sea, Feltham is about as clean as a London borough gets.
The risk that does exist comes from surface water: rain that falls faster than drains and soil can take it, and runs off along roads and into low ground. Feltham grew peas and cabbages on this land for generations before the market gardens gave way to housing and light industry from the 1930s, and tarmac soaks up far less than a cabbage field. Look up the exact address on the Environment Agency's long-term flood risk service, which maps surface water street by street. Two houses on the same road can come out differently.
The climate-adjusted version of the river-and-sea zones, which allows for heavier future rainfall and higher rivers, puts about 1% of postcodes inside the zone. That is a small number, and even under the climate assumptions the agency doesn't expect a river to find its way to Feltham.
For insurance, the lack of river and sea risk helps, because those are the perils insurers fear most. Surface water still counts, and an address flagged high on that measure can carry a higher premium or a larger excess than its neighbours. A quote on the exact property, early in the purchase, will tell you more than anything said about the town as a whole. Particulars that say "not in a flood zone" are right about the river and say nothing about rain.
Across all of Feltham's postcodes, about 14% rate high on at least one flood measure, about 25% medium and about 48% low. These measures include surface water alongside rivers and the sea, and they overlap with the flood zones above, so the two sets of numbers answer different questions and can't be added together. Here, nearly all of the high and medium ratings must come from rain, because the river-and-sea zones are empty.
The Environment Agency's modelled flood extents put 0% of postcodes in the high-risk river-and-sea extent, whether or not defences are counted. In the model, "defended" means a wall or embankment is present. It doesn't mean the house behind it stays dry. In Feltham the question doesn't arise, because neither the defended nor the undefended extent reaches any postcode. No wall is needed where no river reaches, and no wall stops a downpour.
The nearest tide gauge is at Portsmouth, where sea level rose by about 2 millimetres a year across its record from 1962 to 2023. That is a measured past rate on the south coast and says nothing about what happens next. The coast is a long way from Feltham, and so is the sea's flood risk.
No flooding is recorded for any part of Feltham. That is genuinely reassuring, because the records include the floods that people remember and complain about. It shows that nothing has been logged, and that is a little short of proving that nothing has ever happened.
Feltham's flood risk is middling. There is no river or sea risk to speak of, but enough surface-water exposure that the exact address matters more than anything said about the town.