Yes, Hendon carries a real flood risk, and most of it comes from rain running downhill. The river-and-sea flood zones barely touch it. Close to a fifth of its postcodes still rate high on at least one flood measure. A few dozen homes sit in the river's high-risk band. The River Brent gets the headlines, but rain falling on the streets does most of the flooding.
On the Environment Agency's river-and-sea mapping, about 2% of Hendon's postcodes fall in flood zone 2 and under 1% in flood zone 3. Zone 3 is the highest-probability band and zone 2 is the medium-probability fringe beyond it, so each figure is a separate slice of the area. Neither contains the other. By that measure, river flooding affects a small corner of Hendon.
Surface water is the risk that matters here. Hendon is highest around Church End and drops away from there, often steeply, and heavy rain follows the slope into whichever street is lowest. The River Brent runs through Hendon, and in 2009, after a day of notably heavy rain, the Environment Agency warned of flooding along it all the way from Hendon to Brentford. The premises that actually flooded that time were downstream in Brentford and Perivale.
The Environment Agency's climate-adjusted flood zone, which models how the river-and-sea zones could spread under future climate change, covers about 2% of Hendon's postcodes. That's a modelled scenario, and it adds very little to today's map.
Insurers price individual addresses, and for most homes here the river is unlikely to come up. A house at the bottom of a slope, or a basement flat, is where surface water can show up in the quote. Look up the exact address on the Environment Agency's long-term flood risk service and check the surface-water result as well as the river one.
The wider postcode picture is more cautious. Counting any of several flood measures, surface water included, about 18% of Hendon's postcodes rate high on at least one, about 17% medium and about 31% low. A postcode only needs one measure to rate high to count as high, so this figure is always going to look worse than the river zones alone.
Counted as properties, the Environment Agency's river-and-sea risk mapping lists 595 homes and premises across the 26 Hendon postcodes that carry any river risk at all. Of those, 41 are rated high risk, 56 medium, 304 low and 6 very low. Postcodes with no river risk aren't listed at all. That puts the river's real reach at a few dozen front doors, each worth checking.
In the Environment Agency's modelled flood extents, about 0.4% of Hendon's postcodes fall in the high-probability area with defences included in the model, and the same share with defences left out. The model shows nothing that shrinks the high-risk area, and a defence appearing in a model says nothing about whether a particular house stays dry. About 2% of postcodes fall within the low-probability extent without defences.
The nearest tide gauge is at Portsmouth, where sea level rose by about 2 millimetres a year on average between 1962 and 2023. Its distance from Hendon is about how much the sea figures in Hendon's flood risk.
No flooding is recorded inside the area. That's reassuring, but a clean record only goes back as far as someone wrote things down. It can't vouch for every basement on every slope.
Flood risk is a weak spot for Hendon. The river affects only a small number of homes, but surface water reaches far more postcodes than the flood-zone map suggests, and buyers should take it seriously street by street.