Yes, in a narrow band of it, and the band follows the water. The village grew up along the Avon, and the meadows either side of the channel are not decoration. A small share of postcodes sit inside the river and sea flood zones. Most of the village sits outside them completely. Flood risk here is an address question rather than a village one.
The Environment Agency's mapping puts about 4% of Downton's postcodes in flood zone 3, the higher-probability band, and about 7% in flood zone 2. Those two zones are exclusive bands rather than nested ones, so zone 2 is the additional medium-probability fringe lying beyond zone 3, not a larger area containing it. They are read alongside each other, never added together.
Surface water is not published as its own share for this area, so anyone looking for a separate number will not find one. It sits folded into the combined postcode indicator instead. What the village does carry on the formal record is a single river event, logged in January 1959 as the main river exceeding its channel capacity with no raised defences to slow it down, and roughly 1% of postcodes fall inside the historic flood outlines. Defence work followed a later severe flood in 2002.
The climate-adjusted zone layer returns nothing for Downton, with none of its postcodes falling inside it. That is a modelling output on the same set of maps rather than a statement about the next fifty years, and treating a zero as a promise is a mistake the maps themselves never make.
For most of the village, insurance never becomes a conversation. For an address inside zone 3, or one that appears on the risk mapping at all, expect the question on every application form, expect flood to carry its own excess, and expect at least one insurer to decline politely. The order of operations matters: get an indicative quote before instructing a solicitor, not after the survey has already cost money.
Taking every measure together, including surface water, about 9% of Downton's postcodes rate high on at least one indicator, about 9% rate medium on at least one, and about 37% rate low. Those bands overlap the flood zones above rather than adding to them, and the same postcode can appear in both.
Counted as homes rather than postcodes, the Environment Agency's rivers and sea mapping lists 340 properties across the 14 postcodes that carry any risk at all. Ten of them are rated high, eight of those residential. None are rated medium. A further 154 are low and 21 very low. Postcodes with no risk do not appear in that list, so it describes the exposed edge of the village rather than the whole of it.
Then the question the flood maps usually bury. About 5% of postcodes fall inside the modelled high-risk extent undefended, and about 5% fall inside it defended, with roughly 12% inside the low undefended extent. Defended in this context means a defence exists in the model, not that the house behind it stays dry, and the two high-risk shares landing at the same level tells you how much the modelled defences move the number.
On sea level, the nearest tide gauge is at Portsmouth, which has been recording since 1962. Over that run to 2023 it measured a rise of about 2 millimetres a year. Downton is inland and the gauge is a regional reference point rather than a local threat, but it is the measured history rather than anyone's projection.
Downton comes out middling on flooding, which is the honest verdict for a village that chose a river valley and then stayed in it. The village as a whole is fine, a specific handful of addresses are not, and the only way to know which one you are buying is to check the address rather than the place.