Yes. On the official maps, Greenwich is one of the most exposed stretches of the Thames, and how much that matters comes down to the defences. More than half the area is in the highest river-and-sea flood zone. About a hundred homes are rated high risk once the defences are counted. The last recorded flood is nearly a century old. The water is held back, and a buyer here is relying on it staying that way.
In the Environment Agency's river-and-sea flood zones, about 57% of the area's postcodes fall in flood zone 3, the band with the highest chance of flooding. A further 7% fall in zone 2, the medium-probability band just beyond it. The two bands don't overlap, so zone 2 is smaller here because most of the low ground near the river is already counted in zone 3. These zones map where the river could reach, and they show it with no flood defences in place.
The Environment Agency has 11 recorded flood events on file for Greenwich. The most recent was in January 1928, when the main river overtopped its defences. Surface water, the rain that pools when drains can't cope, is a separate risk with its own map, and it feeds into the postcode figures below.
The Environment Agency's climate-change allowance draws a wider line. On that version of the map, about 74% of postcodes fall inside the flood zone.
Insurers price the specific property. A flat several floors up a riverside block and a ground-floor flat or a basement in the same postcode are very different risks to cover, and the premium will reflect that. The street name on the address matters much less.
Counted by postcode, about 16% of Greenwich rate high on at least one flood measure, 21% medium and 38% low. Each figure counts a postcode once if any of several measures flags it, including surface water as well as rivers and the sea. That makes it a broader net than the flood zones above.
Counting homes gives a narrower result. The Environment Agency's rivers-and-sea mapping lists 9,620 properties in Greenwich postcodes that carry some risk. Of those, 109 are rated high, 1,175 medium and 742 low, and 6,437 very low. Only 95 of the high-risk properties are homes. Postcodes with no risk at all don't appear in this count. The flood zones cover more than half the area, while the property count finds about a hundred, and the gap between those two figures is what the defences are worth on paper.
The modelled flood extents show the same thing from a different angle. About 24% of postcodes fall inside the high-probability extent when the model ignores defences, and about 1% when it includes them. "Defended" means only that a defence appears in the model. A wall in a computer model can still be breached, overtopped or left unmaintained, as the 1928 record shows. For any particular home, put the exact address into the Environment Agency's long-term flood risk service and get an insurance quote on the strength of it. The buyer pays for any gap between what the map says and what the insurer charges.
The nearest tide gauge in the national record used here is at Portsmouth. Between 1962 and 2023 it measured sea level rising by about 2 millimetres a year. That is a measured past rate, at a gauge a long way down the coast.
Flood risk is Greenwich's weak point. The modelled defences are what keep it to a hundred high-risk properties, and a buyer here is relying on them.