Partly, and the risk in Crawley comes down from the sky rather than in from a river. The river flood zones cover only a sliver of the town. The sea is nowhere near. About one postcode in five still rates high on at least one flood measure. Crawley's flooding starts at the drains, not the riverbank.
On the Environment Agency's river-and-sea mapping, about 2% of Crawley's postcodes sit in flood zone 3, the highest-probability band, and about 4% sit in flood zone 2, the medium-probability fringe beyond it. The two bands don't overlap, so zone 2 is the extra ring around zone 3, not a bigger area containing it. The town has no major river, only the streams that feed the River Mole, including the Ifield Stream and the Gatwick Stream, and the zones cling to them.
Surface water is where the risk sits. It isn't broken out as its own figure here, but it is folded into the postcode indicators below, and it is what turns a small river footprint into a town-wide question. A new town has a lot of hard surfaces and roads, and a heavy downpour doesn't check the flood zone map before it lands.
The Environment Agency's climate-adjusted mapping, which redraws the zones with an allowance for future rainfall, puts about 7% of postcodes inside a flood zone. That is a forward look at how far the zones could reach, not a promise that they will.
For insurance, a home in or near a mapped zone can mean a higher premium or a longer list of questions on the application, and a surface-water history counts just as much as a river one. Get a quote on the exact address before paying for a survey, because the insurer will look at the property, not the town's average.
Across all flood measures together, including surface water, about 20% of postcodes rate high on at least one, 21% medium and 37% low. These bands overlap with the zone figures above and measure something broader, so they should never be added to them. The high share catches every postcode where any single indicator reaches the top band, which is exactly why it is so much bigger than the river zones.
Counted as homes rather than postcodes, the Environment Agency's rivers-and-sea mapping lists 5,958 properties in postcodes carrying some risk, of which 731 rate high, 213 medium, 1,745 low and 170 very low. Of the high-risk properties, 624 are homes rather than commercial buildings. Postcodes with no river or sea risk don't appear in this count at all, so it describes the exposed edge of the town, not all of it.
On whether anything stands between the water and the house, about 2% of postcodes fall inside the high-probability river extent with no defence in the model, and about 2% fall inside it with a defence present. A modelled defence is not a guarantee, and a seller who calls a property defended is describing a line on a map, not a dry kitchen. There are 46 recorded flood events in the area, the latest in January 2014, when an ordinary watercourse overtopped its channel with no raised defences in place.
The nearest tide gauge, at Portsmouth, recorded sea level rising at about 2 millimetres a year across its record from 1962 to 2023. That is a measured historic rate on the coast, and for an inland town like Crawley it is background rather than a threat.
Flood risk is Crawley's weakest point: the rivers are a minor threat, but rain falling on a town this built-up hits a lot of doorsteps. Check the exact address on every measure, surface water included, because the town-wide average won't tell you anything about your street.