Pimlico is flood country on paper. Practically every postcode sits in the highest river-and-sea flood zone. About two in five postcodes rate high on at least one flood measure. Only a couple of properties are rated high risk once the river defences are counted. The paperwork is alarming, and the record is much calmer.
The Environment Agency's flood zones put near enough 100% of Pimlico's postcodes in Flood Zone 3, the high-probability band for flooding from rivers and the sea. Flood Zone 2, the medium-probability fringe beyond that, holds under 1%, because there's almost nothing left outside Zone 3 for it to cover. Thomas Cubitt built the district on reclaimed marshland in the 1820s, and the zone map still remembers what the ground was before he arrived.
Surface water is a separate risk. It comes from rain that lands faster than the drains can clear it, and it can reach a street the river never touches. The river zones above don't count it. It turns up in the postcode-level measure further down.
The Environment Agency's climate-adjusted flood zone, which models how the zones would grow under a changing climate, also takes in near enough 100% of postcodes. In Pimlico there is no more room for the zone to grow.
For insurance, a Flood Zone 3 postcode is the first thing an insurer's system checks, and a near-universal zone means almost every home here gets flagged, whatever its floor level. Ground-floor and lower-ground flats in the converted terraces are where cover and premiums tend to bite hardest. Get an indicative quote for the specific flat while the survey is still being arranged.
The Environment Agency's postcode-level picture combines several flood measures, surface water among them, and counts a postcode under a level if any one of those measures puts it there. By that count, about 40% of Pimlico's postcodes rate high on at least one measure, 29% medium and 34% low. A postcode can show up in more than one band, so the shares overlap.
The more useful number is homes. The Environment Agency's rivers-and-sea mapping lists about 6,700 properties in Pimlico, and only postcodes carrying some risk make the list at all. Of those, two properties are rated high risk, one of them residential, none are rated medium or low, and about 6,300 are rated very low. That property count allows for the defences, while the zone map leaves them out.
The defence question has a strange answer. In the Environment Agency's modelled flood extents, about 27% of Pimlico's postcodes fall inside the high-probability extent with no defence recorded, and 0% fall inside it with a defence recorded. Low-probability undefended extents cover about 41%. Even where a defence does appear in that model, it only means a structure is present. It says nothing about whether a particular basement stays dry. The Environment Agency has recorded five floods here, and the most recent was in 1928, when the main river overtopped its defences.
The nearest tide gauge in the national record is at Portsmouth, where sea level rose at about 2 millimetres a year over the gauge's measurements from 1962 to 2023. That's the rate recorded on the south coast, a long way downriver from Millbank, and a buyer should take it for what it is: the nearest reading on record, not a measurement of this river.
Pimlico's flood position is poor. Almost all of it is mapped as high risk, insurers read those maps, and the calm record and the low property count can't take that flag off a single postcode.