Mostly no: the houses sit on the hill, and the water stays in the valley. Only about one postcode in fifty falls in the highest-risk river flood zone. None of the homes are rated at high risk from rivers. No past flooding is on record. What risk there is stays down by the Bybrook, away from most of the houses.
Start with rivers and the sea. The Environment Agency's river-and-sea flood zones take in about 2% of Box's postcodes in Zone 3, the highest-probability band, and about 1% in Zone 2, the medium-probability fringe beyond it. The two bands don't overlap, so the smaller Zone 2 figure is a separate strip, not a subset. The geography explains the low numbers: the village is built on higher ground above the steep-sided valley of the Bybrook, and rivers are not in the habit of flowing uphill.
Surface water is the other half, and the same steep ground cuts both ways. Heavy rain on valley sides runs off fast rather than pooling on the hilltops, which suits most homes but not whatever sits at the bottom of the slope or along the lanes that act as drains in a storm. There is no separate surface-water share for Box in the Environment Agency figures used here; it appears folded into the postcode-level measure below.
Looking forward, the Environment Agency's climate-adjusted flood zone covers about 3% of postcodes, a modest step up from today's zones. That's a projection of how the modelled zone grows under a changing climate, not a date on which anything floods.
For insurance, a low-risk village doesn't guarantee a low-risk quote. Insurers price the individual address, so a cottage by the brook and a house on the ridge in the same village can get very different answers. Put the exact address into the Environment Agency's long-term flood risk checker and get an indicative quote before instructing a solicitor, not after exchange, when the surprise is harder to walk away from.
At postcode level, taking rivers, sea and surface water together, about 3% of Box's postcodes rate high risk on at least one measure, about 2% medium and about 8% low. These bands overlap with the flood-zone shares above and can't be added to them. A postcode lands in a band if any single measure puts it there.
Counting properties is more useful than counting postcodes. The Environment Agency's rivers-and-sea mapping lists five postcodes in Box carrying some risk at all, holding 48 properties between them. Of those, 10 properties are at high risk, 1 at medium and 5 at low, and none of the high-risk properties are homes. Postcodes with no river or sea risk don't appear in that count at all, which is why the total is small.
Then there's the question of defences. The share of postcodes inside the modelled high-risk extent is about 2% whether or not the model includes flood defences. In plain terms, the defences in the model make no difference to the high-risk footprint here. "Defended" only ever means a defence is present in the model, not that a property behind it stays dry, and in Box the distinction barely comes up.
The nearest tide gauge on record is Portsmouth, where the sea rose at about 2 millimetres a year over its record from 1962 to 2023. That's a measured historic rate at the coast, and for a Wiltshire valley village it is background reading rather than a threat.
Box has no recorded flooding across the area. That's reassuring, and it's worth taking at face value, but a clean record means nothing got written down, not that water has never crossed a lane. Local knowledge about the lower roads is worth an extra question to the vendor.
Flood risk is one of Box's strengths: the homes stand high above a small river, and the handful of properties in harm's way are mostly not ones anyone sleeps in.