Yes, and most of it has nothing to do with a river. Hardly any postcodes sit in the river-and-sea flood zones. About one in six rate high risk on at least one flood measure. Fifty properties carry a high risk from rivers alone. The danger is the rain that has nowhere to go, not the map most buyers check.
On the Environment Agency's river-and-sea flood zones, about 1% of the area's postcodes sit in zone 3, the highest-probability band, and under 1% sit in zone 2, the medium-probability fringe beyond it. The two zones are separate bands, so zone 2 being the smaller number is not a mistake. The records hold two flood events, the latest in July 2007, when a main river overtopped because its channel could not carry the water and there were no raised defences in the way.
Surface water is the part the river zones miss entirely. Water that pools on roads, gardens and low ground after heavy rain does not care which flood zone a house sits in, and a buyer who checks only the river map and relaxes has checked the wrong thing. The measures further down fold surface water in, which is why they look so different from the zone figures.
The Environment Agency's climate-adjusted zones, which allow for heavier future rainfall and higher river flows, put about 2% of postcodes inside the flood extent. That is a modelled forward look, and it is small, but it points in one direction.
For insurance, the high-risk pockets are what count. Homes flagged high risk can face higher premiums, larger excesses or fewer insurers willing to quote, and a surface-water flag can do that as readily as a river one. Getting a quote on the exact address before instructing a solicitor costs nothing and prevents the kind of surprise that arrives after exchange.
At postcode level the picture widens. Counting any flood measure, surface water included, about 16% of postcodes rate high risk on at least one measure, 17% rate medium on at least one, and 37% rate low on at least one. These bands overlap with the river-and-sea zone figures and with each other, so they cannot be added together or read as the same thing as the zones.
Counting homes lands harder than counting postcodes. The Environment Agency's rivers-and-sea mapping lists 22 postcodes carrying some risk, covering 520 properties. Of those, 50 are at high risk, 29 at medium and 24 at low, and 34 of the high-risk properties are homes. Postcodes with no river-and-sea risk do not appear in the count at all, so those 520 are the ones worth looking at, not the whole area.
Defences make no difference to the modelled high-risk share. About 1% of postcodes sit inside the high-probability flood extent with defences left out, and the same 1% with defences included. A defence appearing in a model is not the same as a house staying dry, and nobody selling a property will volunteer that distinction.
Sea level is a distant concern for an inland parish. The nearest tide gauge, at Portsmouth, recorded a rise of about 2 millimetres a year across its record from 1962 to 2023. That is a measured historic rate on the coast, not a forecast for Swindon's north-eastern suburbs.
Flooding is Stratton St Margaret's weak spot, driven far more by surface water than by rivers. Anyone serious about a house here should run the exact address through the Environment Agency's long-term flood-risk check before making an offer, not after the survey.