Yes. Woodford Green has a real flood risk, and most of it comes from rain with nowhere to go. Very few postcodes are in the river flood zones. About a quarter carry a high-risk flag once surface water is counted. Almost no homes are at high risk from rivers. The trouble is the rain running off the roads, and an area with this much hard surface has plenty of it.
The Environment Agency's river-and-sea flood zones barely touch the place. About 3% of the area's postcodes are in Flood Zone 3, the highest-probability zone, and about 4% more are in Flood Zone 2, the medium-probability fringe beyond it. The two are separate bands, so the zone 2 share is on top of the zone 3 one. On that measure Woodford Green is mostly dry.
Surface water is a different matter, and the river zones don't measure it at all. It comes from heavy rain that the drains and the clay cannot take away fast enough, and it collects in dips in the road, low gardens and basements, wherever the street happens to slope. The single most useful check here is the Environment Agency's long-term flood risk service for the exact address, and the surface-water result in particular. A house well outside every river zone can still sit at the bottom of a road that drains into its front garden.
The Environment Agency's climate-adjusted mapping widens the river-and-sea zone to about 8% of the area's postcodes. That figure models how the zone could grow as rainfall changes over the coming decades. It doesn't mean anything will flood in a given year.
For insurance, the picture splits in the same way as the risk. A home outside the river zones and clear of surface-water flags should be routine to insure. A home with a high surface-water flag can face higher premiums or a flood excess, whatever the river maps say. Get a quote early on any house that matters to you.
Look at each postcode on every measure the Environment Agency publishes, surface water included, and the share at risk jumps. About 26% of the area's postcodes rate high on at least one measure, about 27% medium on at least one, and about 44% low on at least one. Each figure counts a postcode once if any single measure puts it at that level, which is why the totals look so different from the river zones alone.
Counted as properties, the river-and-sea picture is small. The Environment Agency's mapping lists 2,233 properties in the 71 postcodes here that carry some river or sea risk. Of those, 4 are at high risk, 143 at medium and 1,347 at low, with 24 more at very low risk. None of the high-risk properties are homes. Postcodes with no river or sea risk are not listed at all, so these numbers cover only the part of Woodford Green that has some exposure.
The Environment Agency has 81 recorded flood events here. The most recent was in December 2000, when a main river burst its banks with no raised defences in the way. That event is the reason the defences question below matters.
In the modelled high-risk river extent, about 3% of postcodes have no defence in the model and about 1% have one. A defence in the model means a wall or embankment exists in the calculation. It doesn't promise a dry kitchen, and it lowers the chance of flooding without taking it away. For most of the small high-risk area, though, nothing stands in the way at all.
Flood risk is a genuine weak spot for Woodford Green, mostly because of surface water. The river zones look reassuring, but a quarter of the postcodes deserve a closer look at the rain.