Mostly no, and the part that is at risk has nothing to do with the river. Almost nothing here sits in the river-and-sea flood zones. The last recorded flood event was in the seventies. Around one postcode in nine carries a high rating on some flood measure. The water that troubles this town falls on it rather than arriving down the valley.
Start with rivers, because a town sitting in two of their valleys ought to be in trouble and largely is not. The Environment Agency's mapping puts around 0.3% of postcodes in flood zone 3, the highest-probability river-and-sea band, and none at all in zone 2, which is the medium-probability fringe lying beyond zone 3 rather than wrapping around it. The historic record broadly agrees. Nineteen flood events are on file for the area, around 3% of postcodes fall inside a historic flood outline, and the most recent dates to May 1979, a main-river event caused by the channel running out of capacity with no raised defences involved. The Somer and the Wellow Brook have been left enough room, which is more foresight than most former industrial towns managed.
Surface water is the different story. Rain landing on a town built across two valley floors, with hard surfaces above it and gradients doing what gradients do, has somewhere to go and it goes there quickly. Once the full set of flood indicators is used rather than the river-and-sea zones alone, around 11% of postcodes carry a high rating, and the gap between that and the 0.3% in zone 3 is almost entirely rainwater with nowhere to drain.
Looking forward, the climate-adjusted mapping takes around 6% of postcodes into a flood zone. That is the Environment Agency modelling wetter winters and heavier downpours onto the same geography, and it moves river risk from negligible to worth checking for a small minority of addresses.
For insurance, most homes here will be unremarkable to an underwriter. The minority inside a modelled extent are a different conversation, and the answer varies address by address rather than street by street, because surface-water risk turns on which side of a slope you sit and where the drains give up. Get an indicative quote on the specific address before instructing a solicitor, not after.
On the postcode picture across all measures, around 11% rate high, around 14% rate medium and around 35% rate low on at least one indicator. That phrase carries weight: it folds surface water in alongside rivers and sea into a single flag, so those bands overlap with the flood-zone shares rather than stacking on top of them.
Counted as homes rather than postcodes, which is the more useful unit, the Environment Agency's rivers-and-sea mapping identifies 5 properties at high risk, 5 at medium and 1 at low, out of 106 properties across the four postcodes that carry any river-and-sea risk at all. Just one of the high-risk properties is residential. Postcodes with no risk never appear in that list, which is why the total looks so small against a town of this size.
On whether anything stands between the water and the house, around 0.3% of postcodes sit inside a modelled high-risk extent with a defence present, and the same share sit inside one without. Present in the model is not the same as protected. A defence has a design standard it can be pushed past, and its presence tells you somebody expected water here, which is not the reassurance it sounds like.
Sea level barely enters into it this far inland, though the record exists. The nearest tide gauge, at Portsmouth, has measured a rise of around 2 millimetres a year across its 1962 to 2023 record. That is measured history rather than a forecast, and in any case the water in these valleys is heading away towards the Avon rather than arriving from the coast.
Flood risk here sits in the middle: not a reason to walk away, not something to wave through either. The rivers have been given room. It is the rain, and which slope your particular house sits on, that decides whether you are one of the awkward ones.