East Ham carries more flood risk on paper than almost anything else about it. About half its postcodes fall in the highest river-and-sea flood zone. With climate change allowed for, that grows to about seven in ten. Not one flood is on record. The map and the memory disagree, and the insurer reads the map.
In the Environment Agency's river-and-sea flood zones, about 51% of East Ham's postcodes fall in Flood Zone 3, the highest-probability band, and about 2% more fall in Flood Zone 2, the medium-probability fringe that runs beyond it. The two are separate bands, so Zone 2 being the smaller number is how the map is drawn. Low ground between the Thames and the Roding was always going to colour in like this. Beckton, which this page also covers, was open marshland known as the East Ham Levels before the gasworks and the sewage works brought houses, and the flood zones still follow the old marsh more closely than the street plan does.
There is no separate surface-water share for East Ham in this assessment. Rain falling on hard ground is folded into the postcode-level picture further down, alongside rivers and sea.
The Environment Agency's climate-adjusted flood zone, which redraws the map for future rainfall and sea levels, takes in about 72% of East Ham's postcodes. That is the modelled shape of the zone under a changing climate, and it attaches no date to anything.
For insurance, a postcode in Flood Zone 3 is the first thing an underwriter checks, and the premium and any excess follow from it. A quote on the exact address is the one check worth doing early here, because two houses on the same East Ham terrace can sit either side of a zone line and get quoted as different risks.
A broader count looks at every postcode on at least one of several flood measures, surface water included. On that basis about 8% of East Ham's postcodes are at high risk on at least one measure, 14% at medium and 66% at low. Because it counts any measure, it overlaps with the zone figures and answers a different question.
Counting homes gives a calmer picture. The Environment Agency's rivers-and-sea risk mapping lists about 10,200 properties in East Ham, and only postcodes carrying some risk appear in it at all. Of those, just 1 property is at high risk, none at medium, about 8,600 at low and 51 at very low, and not one of the high-risk properties is a home.
Then comes the question of what stands in the way. In the Environment Agency's modelled flood extents, about 26% of East Ham's postcodes fall inside the high-probability extent with no defence counted, and none fall in the defended version of that extent. A defence showing up in a model is a line on a drawing, and on this measure East Ham's high-risk postcodes have no such line to point to.
The nearest tide gauge with a long record is at Dover, where sea level rose by about 2.2 millimetres a year between 1961 and 2010. That is the rate measured there over those years.
None of East Ham falls inside the Environment Agency's record of historic flood outlines. That counts for something on land this low, though a blank record only says nothing was mapped.
Flood risk is East Ham's weak point, measured by how much of it the river-and-sea map claims. The homes have stayed dry so far, and the paperwork is written as if they might not.