Yes. Stratford grew up at a ford, and much of the land around it still counts as floodplain. About three in ten postcodes fall in the highest river-and-sea zone. On the climate-change version of the map, that rises to almost half. A town named after the spot where you could wade across the river was never going to stay bone dry.
In the Environment Agency's river-and-sea flood zones, 30% of Stratford's postcodes are in Zone 3, the high-probability band, and another 4% are in Zone 2, the medium-probability fringe outside it. These are separate bands, so the 4% comes on top of the 30%. Zone 3 shows where the River Lea and the old channels around it could reach, and Stratford was settled where those channels came together.
The Environment Agency doesn't publish a separate surface-water share for Stratford, so rain that overwhelms the drains shows up only in the combined postcode measure further down. The historical record is clearer. The Agency holds 111 recorded flood events for the area, and about 14% of the area falls inside its outlines of historic flooding. The most recent recorded event was in December 1947, when a main river flooded after its channel ran over capacity at a point with no raised defences.
The Agency also maps a version of the river-and-sea zones with an allowance for climate change. On that map, the share of Stratford's postcodes in the zones rises to almost half. The map shows what planners are told to allow for when they plan new homes.
An insurer prices a property on its own exact location, so two flats in neighbouring blocks can get quite different quotes. In a high-zone postcode, expect the insurer to ask more questions and possibly charge more. A new flat by the Lea and an older terrace further from the water are different risks, even when both carry an E15 postcode.
The broadest measure counts a postcode if it rates high, medium or low on at least one of several flood measures, surface water included. On that basis, about 10% of Stratford's postcodes rate high on something, 22% medium and 52% low. Because one bad measure is enough to put a postcode in a band, this count reads higher than any single map.
Counting homes gives a much smaller number. The Environment Agency's rivers-and-sea mapping covers about 10,160 properties in the postcodes that carry some risk, and postcodes with no risk at all are left out. Of those properties, just two are at high risk and none at medium. Another 853 are at low risk and about 8,450 at very low risk. Neither of the two high-risk properties is a home. The zone maps ignore defences and the property count allows for them, so the zone maps look much worse. To see which figure applies to a particular flat, put the full address into the Environment Agency's long-term flood risk service and compare it with an insurance quote.
The Agency's modelled extents add a detail the zone maps leave out. About 30% of Stratford's postcodes are inside the high-probability extent with no defence present in the model, and the defended share is 0%. A defence being in the model would only mean a structure exists. It wouldn't mean the house behind it stays dry. Here, for those postcodes, the model doesn't record a defence at all.
The nearest tide gauge with a long record is Portsmouth, where sea level rose by about 2 millimetres a year between 1962 and 2023. Portsmouth is a long way from Stratford, but the Lea's branches here were tidal when the Roman road crossed them.
Stratford's flood risk is poor on the maps lenders and insurers check first, even though the Environment Agency counts very few homes at high risk. Treat the flood check as part of every purchase here, whatever the property count says.