Not from the river, which is the surprise given the town sits in the Avon valley. Nothing here falls inside the official river-and-sea flood zones. Nothing has been recorded flooding either. What risk exists comes from rain landing on the ground rather than the Avon coming over its banks, and it affects a minority of postcodes. The famous river runs through the middle of town and behaves itself.
Start with rivers and the sea, because that is the map most buyers have seen. The Environment Agency's flood zones cover none of Amesbury: zero percent of the area's postcodes sit in flood zone three, and zero percent in flood zone two. Those two zones are separate bands rather than one inside the other, with zone two the additional medium-probability fringe sitting beyond zone three, so it is worth being clear that both come back empty rather than one absorbing the other. For a town built around several bends in the Avon on the southern edge of Salisbury Plain, that is a better result than the geography advertises.
Surface water is where the actual risk lives. Rain that arrives faster than the chalk and the drains can take it has to go somewhere, and on a valley floor it goes downhill into the same low ground the river uses. That is the mechanism behind the postcode-level ratings below, and it is a different thing entirely from the river rising.
The forward look does not change the picture. With the climate change allowance applied, which pushes the modelled zones outward to account for higher future flows, the share of Amesbury postcodes falling inside them is still zero percent. That is unusual and worth noting: plenty of places sit outside the current zones and inside the climate-adjusted ones.
For insurance, that combination is about as good as a valley town gets. A property outside the river-and-sea zones with no recorded flood history is straightforward to insure on standard terms in most cases. The caveat is that insurers price the address, not the town, and a house on the lowest ground near the water with a surface-water rating against it can still attract questions and a higher excess. Get an indicative quote before you instruct a solicitor rather than after.
The broader postcode indicator, which folds surface water in alongside rivers and the sea and flags a postcode if it rates on at least one measure, gives around 8% of Amesbury postcodes a high rating, around 11% a medium one and around 24% a low one. Those bands overlap with the zone figures rather than adding to them, and they are counting postcodes rather than individual homes. Most of the town carries no rating at all on any measure, which is the number that matters most and the one nobody quotes.
On defences, the modelling is blunt: zero percent of postcodes sit inside a high-risk flood extent with a defence present, and zero percent inside one without. There is nothing here for a defence to stand in front of. That is not the same as saying a defence would protect you if there were, because a defence being present in a model tells you a structure exists, not that a given house stays dry behind it.
The nearest tide gauge with a long record is at Portsmouth, where the measurements from 1962 to 2023 show sea level rising at around 2 millimetres a year. That is a measured historic rate over six decades rather than a projection, and Amesbury sits well inland on a river valley, so it belongs here as context rather than as a threat to the town.
No historic flooding is recorded for the area at all. That is genuinely reassuring, and it is also not proof that water has never come up somewhere unlogged in a place occupied since long before anyone wrote anything down. Recorded absence is evidence, not a guarantee.
Middling, and only because of surface water. The river the town was built on turns out to be the least of its problems, and the risk that remains is the sort that lands on individual addresses rather than whole streets. Put the specific address into the Environment Agency's long-term flood risk tool before you commit, because a town-level answer of low risk is no comfort at all if your house is one of the ones with a rating against it.