Yes, Peckham carries a real flood risk, and it shows up on more than one map. About a quarter of the district falls in the highest river-and-sea flood zone. A quarter of postcodes rate high on at least one flood measure, surface water included. Allow for climate change and the river-and-sea zone stretches to about half the district. The one consolation is a blank history, with no flooding on record.
On the Environment Agency's river-and-sea mapping, about 27% of Peckham's postcodes are in flood zone 3, the high-probability band. A further 3% are in flood zone 2, the medium-probability fringe that lies beyond zone 3. The two bands don't overlap, which is why the fringe can be the smaller number of the two.
Surface water has no separate figure here. It is folded into the postcode-level measures further down, which is where a downpour that overwhelms the drains on a built-up street shows up. Peckham once had its own river, the Peck, and enclosed it in 1823, so the water a modern buyer is likeliest to meet now arrives from the sky and leaves through the drains, when they cope.
The Environment Agency's climate-change version of the zone map covers about 53% of the district's postcodes. That is a modelled scenario of how the zone grows as conditions change, with no date attached to any of it. It still moves a lot of addresses from someone else's problem to a question for the buyer.
Insurers price flood cover on the exact address, and in a district where a quarter of postcodes fall in the top zone, plenty of addresses will get asked more questions and quoted more for the answers. The practical step is to get an indicative buildings-insurance quote on the specific property while the solicitor is still at the paperwork stage, since a premium is the quickest way of finding out what the flood map means for that one house.
Counted another way, about 25% of Peckham's postcodes rate high on at least one of several flood measures, about 33% medium and about 47% low. Those measures cover rivers, the sea and surface water together, and a postcode only needs one of them to qualify, so the shares overlap each other and also overlap the zone figures above. They answer a different question from the zone map and shouldn't be added to it.
On whether anything stands between the water and the house, about 2% of postcodes lie inside the Environment Agency's high-probability flood extent with no defence present in its model, and none lies inside that extent with a defence. "Defended" in that model only ever means a defence is drawn in. For the small share it catches here, the model doesn't even draw one.
The nearest tide gauge in the national record is at Portsmouth, where sea level rose at about 2mm a year between 1962 and 2023. That is the rate measured at that gauge over those years, and the fact that the nearest one is on the south coast tells you how indirect the sea's interest in Peckham is.
The Environment Agency records no historic flooding anywhere in Peckham's postcodes. That counts for something, and it only covers events somebody wrote down.
Flood is the weak point in Peckham's case: a quarter of the district in the top zone and a climate map that reaches half of it put this below average, and the street matters more than the postcode.