Yes. In Harold Wood the flood risk comes mostly from rain rather than from any river. The river flood zones barely touch the place. About a third of its postcodes still carry a high flood flag. The difference between those two figures is surface water on suburban streets. "Not in a flood zone" is true here and does not settle the question.
On the Environment Agency's river-and-sea mapping, about 0.4% of Harold Wood's postcodes are in Flood Zone 3, the highest-probability band. Another 0.4% are in Flood Zone 2, the medium-probability fringe outside it. The two bands do not overlap, and together they cover less than 1% of the place. Only one flood is on record, in December 1968, when a main river overflowed its channel with no raised defences in place. The River Ingrebourne once marked the old parish boundary, and in modern flood records it hardly appears.
Surface water is the main risk. It is rain that falls faster than drains and soil can take it, and it pools wherever the ground is lowest. The river zones account for almost none of Harold Wood's flood flags, so nearly all of the risk in the postcode figures below comes from the other measures, surface water among them. A slight dip in a road can matter more here than any distance from a river.
The Environment Agency's climate-adjusted zone, which allows for heavier future rainfall and higher river flows, covers about 1% of postcodes. That is more than today's zones, but only slightly.
Insurers look at more than whether a home is in a river flood zone. Surface-water flags are part of how they set cover and premiums, and a street that pools after a storm can cost more to insure than its river map suggests. The phrase "not in a flood zone" in a property listing is literally true for almost every home in Harold Wood. It says nothing about rain. Look up the exact address on the Environment Agency's long-term flood-risk service and read the surface-water result, not just the rivers-and-sea one.
At postcode level, Harold Wood looks much worse. About 32% of postcodes rate high on at least one of several flood measures, rivers, sea and surface water included. About 29% rate medium on at least one, and about 51% low on at least one. One postcode can carry several flags, so a single risk level does not describe a street, and the numbers vary from one road to the next.
The rivers-and-sea mapping also counts individual properties. Only postcodes with some risk are listed, and they hold 498 properties. Of those, 2 are at high risk, 6 at medium, 88 at low and 6 at very low. Just one high-risk property is a home. On the river measure alone, Harold Wood has hardly any homes at serious risk. The trouble is that the river measure is not the main source of risk here.
On whether anything holds the water back, about 0.4% of postcodes lie inside the high-risk modelled flood extent with no defence included, and about 0.5% lie inside it with a defence in the model. Either way, these are tiny shares. "Defended" here only means a structure appears in the Environment Agency's model. It does not mean the water stays out of the house.
Flood risk is one of Harold Wood's real weaknesses. The rivers are not the problem. Rain is, falling on streets that do not drain fast enough, across about a third of the place.