Norwood Green's flood risk comes from rain, and the river maps give it a clean bill of health. No postcode falls in a river or sea flood zone. About one postcode in eight is still rated high on at least one flood measure. A canal runs along one edge and a canalised river along another, and neither is the problem. Water that falls on the place and has nowhere to go is the risk to watch.
None of Norwood Green's postcodes falls in the Environment Agency's river-and-sea flood zones: 0% in zone 3, the highest-probability band, and 0% in zone 2, the medium-probability fringe beyond it. The agency's property-level count for rivers and sea lists one postcode with any risk at all, covering 13 properties, of which one is at low risk and none is at medium or high. For a place bounded by the Grand Union Canal and the canalised Brent, the water on the map is remarkably well behaved.
Surface water is a different story, because it ignores rivers entirely. About 12% of postcodes here have a high rating on at least one flood indicator, and with the river-and-sea zones empty, heavy rain overwhelming drains and low spots is what puts them there. It can catch a single street or a single dip in the road while the next street stays dry. Put the exact address into the Environment Agency's long-term flood-risk service and look at the surface-water layer specifically, because that is the one that matters here.
Adding the Environment Agency's allowance for a wetter climate does not change the river picture: 0% of postcodes fall inside the climate-adjusted flood zone. The rivers are not expected to reach any further into Norwood Green than they do now, on that model. Rain is the variable the model handles less neatly.
Insurers price on risk at the individual address, and a clean river-and-sea record helps. A postcode flagged for surface water can still push up a quote, and the one fact a listing will lead with is that the home is "not in a flood zone", which answers the river question and is silent on the rain.
Across all of Norwood Green's postcodes, about 12% rate high on at least one of several flood measures, 18% rate medium and 48% rate low. That count takes in surface water alongside rivers and sea, and a postcode only needs one measure to qualify, so it is the broadest view on offer. It is also the one that matches how flooding here actually works.
On the Environment Agency's modelled flood extents, 0% of postcodes are in the high-probability extent with defences in place and 0% without them. No defence stands between the rivers and the houses in the model because the model has no high-risk river flooding to defend against. A defence appearing on a model would only mean something is built there; it would say nothing about whether it holds. Here, the question does not come up.
The nearest tide gauge in the national record is at Portsmouth, where sea level rose about 2mm a year between 1962 and 2023. That is a measured rate at a south-coast harbour, many miles from here, and it has no bearing on the canal at Three Bridges.
No flooding has been recorded in the area. That is good news and fits the empty river zones, though a missing record means no flood was logged, which is not quite the same as no flood ever happening.
Norwood Green has a middling flood risk, with rivers and the sea out of the picture and rain doing all the work, so the decision comes down to which street the house is on.