Not from rivers, but rain is another matter. No postcode here sits in a river or sea flood zone. About a quarter still rate high on at least one flood measure. No flooding is on record in the area. The river maps say relax, and the rain maps don't agree.
On the Environment Agency's river-and-sea flood zones, Southwater comes out clear: none of its postcodes sit in Flood Zone 3, the highest-probability band, and none sit in Flood Zone 2, the medium-probability fringe beyond it. The agency's property-level count for rivers and sea tells the same story, with no homes at high or medium risk. If the only question on your list is whether a river will come over the bank, the answer here is no.
That isn't the only question. Flooding also comes from rain that falls faster than the ground and drains can take it, and none of that appears on a river-and-sea map. In Southwater the flood ratings come from those other sources, surface water among them, and they vary from one street to the next. Buyers who stop reading at "not in a flood zone" are reading half the report.
The Environment Agency's climate-adjusted zone, which models how the river-and-sea picture shifts under future conditions, also covers none of Southwater's postcodes. On that measure the forward look matches the present one.
Insurers price by address, using their own flood models, and those models include surface water as well as rivers. A clean river-and-sea result won't guarantee a clean quote, and a postcode with a high rating on some other measure can come back with a higher premium or awkward questions. Get an indicative quote on the specific address before you instruct a solicitor. Finding out after exchange is the expensive way round.
The broader postcode picture is where the risk shows up. About a quarter of Southwater's postcodes, 25%, are rated high on at least one flood measure, 23% medium and about 45% low, with surface water counted alongside rivers and sea. These bands overlap and are a different measure from the flood zones above, so don't add them together or read them as contradicting each other. Together they say the river risk is nil and the other risk is patchy.
The Environment Agency's modelled flood extents put none of Southwater's postcodes in a high-risk extent, either with defences in place or without. There's nothing for a defence to hold back, so whether one exists doesn't come into it. A defence in the model wouldn't have been a guarantee anyway.
The nearest tide gauge is at Portsmouth, where records from 1962 to 2023 show sea level rising by about 2 millimetres a year over that period. That's a measured historic rate, not a forecast, and for an inland village with no postcode in a sea flood zone it matters mostly to the south coast.
The area has no recorded historic flood outlines. That's worth something, but it isn't proof that no garden or road has ever gone under. Surface water flooding often goes unrecorded unless enough homes are affected to prompt a survey.
Flood risk is Southwater's weak spot, not because of rivers or the sea but because of rain, and a quarter of postcodes carrying a high rating is too many to wave away. Check the exact address on the Environment Agency's long-term flood-risk service before you make an offer, and don't let the village-wide answer stand in for it.