Mostly no, and where the answer turns to yes the water arrives from underneath. None of Andover sits in the highest river-and-sea flood zone. A thin slice sits in the medium band beyond it. The last recorded flooding here came up through the ground rather than over a bank. The risk is real, narrow, and not attached to the river you would think to watch.
Start with the Environment Agency's river-and-sea flood zones, measured here as the share of the area's postcodes falling inside each. No Andover postcode sits in zone 3, the highest-probability band. About 4% sit in zone 2, which is the additional medium-probability fringe lying outside zone 3 rather than a wider ring containing it, so the two are separate bands and a smaller figure in the higher one is not a contradiction. For a town built along the River Anton, a tributary of the Test, that is a better result than the map of it suggests.
Surface water is a different animal and does not appear in those zones at all, because the zones describe rivers and the sea and nothing else. Rainwater coming off roads, roofs and hard ground is caught by the separate postcode indicators further down this answer, and in Andover that is where the higher ratings come from rather than from the Anton itself.
As a forward look, about 5% of postcodes fall inside the zone that carries the Environment Agency's climate change allowance, a slightly wider footprint than today's zone 2. That is a modelled future extent rather than a statement about any particular winter.
For insurance, this is a workable position rather than a difficult one. Most Andover addresses will be quoted as ordinary risks, and the handful inside the mapped extents are where an insurer starts asking questions and pricing the answers. An indicative quote before instructing a solicitor costs nothing and settles more than a map ever will.
The broader postcode indicators fold surface water in alongside rivers and sea, and rate a postcode on at least one measure. On that basis about 8% of Andover's postcodes come out high, about 12% medium and about 25% low. Those bands overlap the zone figures rather than adding to them, which is exactly why a house can read as clear on one map and flagged on another without either being wrong.
Counted as homes rather than postcodes, the Environment Agency's rivers-and-sea mapping records 373 properties in the area at some level of risk: 3 at high risk, 18 at medium and 171 at low. Only postcodes that carry some risk appear in that count at all, so it describes the exposed edge of the town rather than the town.
On whether anything stands between the water and the building, no Andover postcode falls inside the modelled high-probability extents, defended or undefended, and about 4% sit inside the low-probability undefended extent. Where the word defended does appear, it means a defence exists in the model. It does not mean the house behind it is safe, and it should never be read as though it does.
The nearest tide gauge is at Portsmouth, where the record from 1962 to 2023 shows sea level rising at about 2 millimetres a year. That is a measured historic rate across six decades on the coast, not a forecast, and for an inland town on the Anton it belongs in the context column.
No Andover postcode falls inside the recorded historic flood outlines. The recording system does hold twelve events for the area, the most recent in April 1995, caused by groundwater and a high water table in a watercourse that only runs part of the year. Nothing recorded is genuinely good news. It is not proof that nothing has ever happened, and that caveat carries more weight than usual where the mechanism is groundwater, which rarely leaves a tidy line for anyone to draw.
Flood risk here lands in the middle of the range: not a reason to walk away, not a box to leave unticked on the strength of a reassuring headline. Put the exact address into the Environment Agency's own mapping before you commit, because where the risk is underfoot rather than over the bank, two houses on the same road can get two very different answers.