Yes, though rivers and the sea have nothing to do with it. None of Upper Holloway's postcodes are in a river or sea flood zone. Nearly a third still get a high flood rating on at least one measure. The risk comes from heavy rain with nowhere to drain, and a sunny viewing will never show it.
The Environment Agency's river-and-sea mapping puts none of Upper Holloway's postcodes in Flood Zone 3, the highest-probability band, and none in Flood Zone 2, the medium-probability band beyond it. As far as rivers and the sea go, the area is clear. That covers only one of the ways water gets into a house.
Surface-water flooding happens when rain falls faster than drains and gutters can carry it away, and it collects on roads, in dips and against walls. The river-and-sea zones don't measure it at all, so a flat can be clear on that map and still sit on a street that collects water in a cloudburst. Calling the area Upper does nothing for the drains.
The Environment Agency's climate-adjusted flood zones, a forward look at river-and-sea risk with an allowance for climate change, also put none of the area's postcodes inside them. On that measure, the projected future looks the same as the present.
Insurers price surface water at the level of the individual address, and this is the risk that actually sets premiums here. A flat on a street rated high may cost more to insure, or come with a bigger excess, than one around the corner. Get an indicative quote on the exact flat before you pay a surveyor, because the premium will tell you more about that address than any area-wide figure.
Upper Holloway's postcodes are rated high, medium or low on any of several flood measures, and surface water counts alongside rivers and the sea. On that basis, about 30% are high risk on at least one measure, 28% medium and 44% low. With nothing in the river-and-sea zones, those high ratings are coming from the other measures. A buyer who stops at the zone map has answered the easy question and skipped the one that applies here.
In the Environment Agency's modelled flood extents, none of the area's postcodes fall in a high-risk extent, either with flood defences in the model or without them. The question of whether anything stands between a river and these houses doesn't come up, because the model has no river reaching them. Defences don't help with surface water anyway, which is decided street by street by drains and gradients.
The nearest tide gauge in the record is at Portsmouth, where sea level rose by about 2mm a year between 1962 and 2023. That is a measured past rate at a gauge a long way from north London, and it has very little to do with the water risk in these streets.
There is no recorded history of flooding anywhere in the area. That is reassuring, but it only covers flooding that was reported and mapped. A short downpour that filled a front garden and drained away by morning would leave no mark on the record.
Flood risk is Upper Holloway's main weakness. The risk comes from rain, it is spread across nearly a third of the postcodes, and none of it shows up on the map most people check first.