Romford does have a flood risk, and the river is the smaller part of it. About one postcode in twenty sits in the river's highest-risk zone. About one in five is at high risk once every kind of flooding is counted. Modelled defences don't reduce the high-risk area at all. For a town that moved itself away from its river in the Middle Ages, that's a lot of water still to think about.
On the Environment Agency's river-and-sea flood maps, about 5% of the area's postcodes fall in flood zone 3, the highest-probability band. Another 6% are in flood zone 2, the medium-probability fringe beyond it. Neither band includes the other. The Environment Agency has 12 recorded flood events for the area. The most recent was a main river flood in December 1974, when the channel could not carry the water and no raised defences were in place. Romford's river is called the Rom here and the Beam further downstream, and it has flooded under either name.
The river zones leave rainwater out entirely. Surface water forms where the drains and ground can't take a downpour, and that risk can sit in streets nowhere near a river. The River Rom now runs through the town centre in underground channels, but a river you can't see is still on the map.
Allowing for climate change, the Environment Agency's mapping puts about 14% of postcodes in the river-and-sea flood zones. That is how the zones look once the Agency builds in heavier rainfall and higher flows, and the extra postcodes are ones that look dry on today's map.
Insurers price cover on the individual property, using their own flood models, so two houses on the same road can get very different quotes. A house on the highest-risk land may cost more to insure, carry a higher excess, or be accepted by fewer insurers. Get an indicative buildings quote for the exact address while you are still negotiating, so the cost is known before you commit.
Across every measure combined, including surface water as well as rivers and sea, about 21% of Romford's postcodes are at high risk on at least one of them. About 22% are at medium risk on at least one, and about 40% at low risk. These figures count a postcode once its worst measure reaches each level, so they overlap with the river zones above. That's why they run so far ahead of the zone shares.
Counted as properties, the Environment Agency's rivers-and-sea mapping puts 379 at high risk, 195 at medium risk and 840 at low risk, out of 2,107 properties listed across the area. Only postcodes with some risk appear in that list. Of the high-risk properties, 376 are homes, so almost all of that exposure is residential.
About 5% of postcodes sit inside the Environment Agency's high-risk extent with no defences modelled, and the share is the same about 5% once defences are included. In the model, the defences don't reduce the high-risk area. A defence being present on the map doesn't mean the house behind it stays dry. A sales brochure that mentions a nearby defence is describing the map's legend, not the water.
Romford's flood risk is a real weakness and worth taking seriously. The river zones are fairly narrow, but the wider risk reaches about a fifth of postcodes, and the modelled defences don't shrink the high-risk zone.