Not from rivers or the sea, but rain is another matter. No postcode sits in the river-and-sea flood zones. None is added once climate change is allowed for. About one in seven is still flagged high risk on at least one measure. Rivers aren't the problem here. The problem is water with nowhere to drain.
On the Environment Agency's river-and-sea mapping, 0% of Southborough's postcodes fall in Flood Zone 3, the high-probability band, and 0% in Flood Zone 2, the medium-probability fringe beyond it. The two zones are separate bands, and both are empty. For river and coastal flooding, that is as clean a result as the map gives.
Surface water is where the answer changes. It comes from heavy rain overwhelming drains and running downhill, not from a river bursting its banks, and the zone maps above don't measure it. Surface water is counted alongside the other measures in the postcode indicators below. With the river-and-sea zones empty, any flag a Southborough postcode carries comes from those other measures.
The Environment Agency's climate-adjusted zones, which model the river-and-sea picture with an allowance for a wetter future, also cover 0% of the area's postcodes. Southborough gains nothing from that forward look. That is good news, and it still says nothing about surface water.
For insurance, a clear result on the river-and-sea zones helps, but insurers look at surface water as well, and they price the individual address, not the town. A house on a clear postcode can still get a higher quote if water collects in its road. Get an indicative quote on the exact address before paying for searches, not after.
At postcode level, about 14% of Southborough's postcodes rate high on at least one flood measure, about 11% medium and about 25% low. These bands fold surface water in with everything else, so they overlap with the zone figures above and can't be added to them. They are a separate way of looking at the same ground, and the flags here are carried by the rain, not the rivers.
The Environment Agency's modelled flood extents put 0% of Southborough's postcodes in high-risk areas without defences, and 0% in high-risk areas with defences. On that model, the question of whether anything stands between the water and the house doesn't arise, because the model shows no water reaching the house from a river or the sea. "Defended" in these figures would only mean a defence appears in the model, not that a property is safe. Here there is nothing either way.
The nearest tide gauge is at Dover, which recorded sea levels rising by about 2 millimetres a year over its record from 1961 to 2010. That is a measured historical rate, not a forecast. For a town this far inland, it is background information, not a warning.
No historic flooding is recorded in the area. That is reassuring, but a gap in the record is not proof that water has never come through someone's front door. Neighbours and previous owners are worth asking.
Southborough's flood risk is middling. Rivers and the sea don't threaten it, but around one in seven postcodes flagged high on surface water or another measure means the individual address matters more than the town's clean zone map.