West Norwood has no meaningful river or sea flood risk, but it does have a surface-water problem. No postcodes fall in the river-and-sea flood zones. About one in six still rate high on at least one flood measure once heavy rain is counted. There is no recorded flood history in the area. A town built at the bottom of a bowl has to put the rain somewhere.
The Environment Agency's river-and-sea mapping puts none of West Norwood's postcodes in Flood Zone 3, the highest-probability band, and none in Flood Zone 2, the medium-probability band next to it. With the nearest open water about a kilometre away on average, that's no surprise. "Outside the flood zones" will be true on any West Norwood listing, but it only covers rivers and the sea, and those aren't what floods here.
The risk here comes from rain running off the hills. The centre of West Norwood sits in a bowl with high ground on three sides, so in a heavy downpour water runs downhill towards the middle. The River Effra once ran alongside what is now Elder Road and was prone to flooding. The streets near the valley floor still get the run-off from the slopes around them.
The climate-adjusted version of the river-and-sea zones also covers 0% of West Norwood's postcodes. That allowance models how the zones might grow as rivers and seas rise, and it adds nothing here, because rivers and the sea aren't the problem.
Insurers look at surface water as well as the zone maps, so a home in a postcode flagged for surface water can face higher premiums or more questions than the zone maps suggest. Get a quote for the exact address, and check the Environment Agency's surface-water map for that street, before you commit to a basement flat or a garden on the low ground.
On postcode-level flood indicators, which count rivers, sea and surface water and flag a postcode if any of them applies, about 16% of West Norwood's postcodes rate high, about 13% medium and about 30% low. A postcode only needs one measure to be flagged. Even so, a clean result on the river-and-sea zones next to that many flagged postcodes means the zone maps miss most of what floods here.
None of West Norwood's postcodes fall inside the modelled high-risk flood extent, with or without defences, at 0% in both cases. In that model "defended" only means a defence is present, so neither figure says how safe any particular home is. There is no river flood plain here for a defence to protect, so the comparison doesn't tell you much.
The nearest tide gauge in the national records is at Portsmouth, where sea level rose by about 2 millimetres a year between 1962 and 2023. That's the rate measured there over those years, and with the coast that far from West Norwood it has little to do with flooding here.
The Environment Agency has no recorded flood outlines anywhere in the area. That is reassuring, but the record doesn't go back forever, and the old descriptions of the Effra show that water collected on the valley floor long before anyone mapped it.
Flood risk is West Norwood's weak point. River and sea flooding isn't a concern, but surface water affects enough postcodes on the low ground that anyone buying there should check the street, not just the zone map.