Yes, and more than a village a mile and a bit inland ought to be. Around a fifth of postcodes sit in the highest river-and-sea flood zone. The place takes its name from the Willet, a brook that runs down through Stream and meets the Doniford Brook just beyond the houses. Water has been recorded here more than once. The valley that makes the setting is the same valley that carries the problem.
On the Environment Agency's river-and-sea mapping, around 18% of the area's postcodes fall inside flood zone 3, the highest-probability band, and a further 4% or so fall inside flood zone 2. Those two are separate bands rather than one inside the other: zone 2 is the medium-probability fringe sitting beyond zone 3, which is why it is the smaller of the two numbers here. Nearly a fifth of the village being in zone 3 is not a rounding artefact of a rural postcode covering empty fields. It is where the houses are relative to the brooks.
Surface water is not published as its own share for this area, so anyone wanting the standing-water picture has to read it through the combined postcode indicator further down rather than as a separate figure. What is recorded is history: around 5% of the area falls within historic flood outlines, and 11 flood events have been logged, the most recent in November 2012 and attributed to a main river rather than to drainage backing up. That is the pattern to expect here. The water arrives from a watercourse, not from a blocked gully.
The forward look is worse, and by a distance. Once the Environment Agency's climate change allowance is applied, around 78% of postcodes fall inside a modelled flood zone. That figure is a modelled future extent rather than today's risk, and it is the single number in this answer most worth sitting with. It means the current one-fifth is the low-water mark, not the ceiling.
For insurance, that matters more than the headline. Cover in a zone 3 postcode is generally obtainable but rarely cheap, excesses for flood claims tend to be set well above the standard policy excess, and lenders increasingly ask the question before the valuation does. Get an indicative quote for the specific address before instructing a solicitor. A survey will tell you about the roof, and it will not tell you what the premium does in year three.
Taking every indicator together, including surface water alongside rivers and sea, around 22% of postcodes rate high on at least one measure, around 23% rate medium and around 27% rate low. Those bands overlap the zone figures rather than adding to them, so this is a second view of the same village, not a second village. Roughly a quarter of it carries a high rating on something.
Counted as homes rather than postcodes, the Environment Agency's rivers-and-sea mapping puts 241 properties at high risk, 120 at medium and 41 at low, out of 868 properties across the 40 postcodes that carry any risk at all. Of the high-risk properties, 180 are residential. Postcodes with no risk do not appear in that count, so the total describes the exposed part of the village rather than the whole of it. Two hundred and forty-one homes at high risk in a village this size is the figure a buyer should carry into a viewing.
As for whether anything stands between the water and the house, around 47% of postcodes sit inside the modelled high-risk extent with defences accounted for, and around 47% sit inside it without them. The two numbers matching tells you the defences in the model are not shifting the outcome here. Worth being clear about the word: a defence being present in the model is not a statement that a property is safe, and never has been.
The shoreline management policy for the coast beyond the village is to hold the line across all three planning horizons, twenty, fifty and a hundred years. The nearest postcode sits around 1.2 kilometres from the coast, with the typical one around 2.1 kilometres inland. Hold the line is a stated intention to maintain defences over that period, decided by people who will not be around for the hundred-year horizon. It is not a guarantee, and it is not a defence that already exists. At the nearest tide gauge, Devonport, sea level rose at around 2.35 millimetres a year across the 1962 to 2015 record. That is a measured historic rate, not a forecast.
Flooding is the weakest thing about Williton, and the honest way to put it is that the risk is real, concentrated, and pointed in the wrong direction over time. Check the individual address on the Environment Agency's long-term flood risk tool before you fall for the view.