Elm Park is almost untouched by river and sea flooding, and what risk it does carry mostly comes from rain. Barely any postcodes fall inside the river flood zones. Nearly half carry at least a low reading on some flood measure. About one in twelve carries a high reading. The rivers are rarely the problem here; rainwater that can't drain away fast enough is.
The Environment Agency's river-and-sea mapping puts under 1% of Elm Park's postcodes in flood zone 3, the high-probability band, and under 1% in flood zone 2, the medium-probability fringe beyond it. The two zones are separate bands, so the second figure adds to the first and doesn't include it. Both shares are so small that on this measure Elm Park barely counts as at risk.
Surface water is where the risk lies. Rainfall that overwhelms gardens, roads and drains doesn't follow the rivers, so the river-and-sea zones leave it out entirely. In Elm Park it drives most of the higher readings in the postcode-level picture below. A street a long way from any watercourse can still find itself the low point when a heavy storm arrives.
Allowing for a changing climate, the Environment Agency's modelled flood zone grows to cover about 1% of Elm Park's postcodes. That is a projection of how the modelled zone would spread under the climate assumptions, and it stays small.
For insurance, the river zones will rarely cause trouble here. Insurers also look at surface-water mapping for the individual address, so a house well clear of any river can still be asked questions if its own postcode carries a high rain-driven reading. The quote follows the property, and the estate as a whole tells the insurer very little.
Across Elm Park's postcodes, about 8% rate high on at least one flood measure, about 19% medium and about 47% low. Those readings combine several measures, surface water included, with rivers and sea, and a postcode lands in a band if any one of them puts it there. "Low" means a small chance in any given year, and that is still more than none. The useful check is the Environment Agency's long-term flood risk service, run on the exact address, with the surface-water result read first. That is the line that matters in Elm Park.
Counting properties is more concrete. The Environment Agency's rivers-and-sea mapping lists only 4 of Elm Park's postcodes as carrying any risk at all, holding 23 properties between them. Of those, 3 are at high risk, 3 at medium, none at low and 1 at very low, and none of the high-risk properties is residential. Postcodes with no river or sea risk don't appear in that count at all, so it covers the at-risk corner of the map and nothing else.
On whether anything stands in the water's way, the Environment Agency's high-probability extent covers the same 0.2% of postcodes with defences included in the model as without them. In that model a "defended" postcode simply has a defence present. It says nothing about whether the defence would keep the water out on the night. Here the comparison changes very little, because the share is tiny with or without defences.
The nearest tide gauge, at Dover, recorded sea level rising by about 2 millimetres a year over its record from 1961 to 2010. That is a past measurement from a gauge some distance away, and on its own it says little about the drains on The Broadway.
Elm Park's flood risk is middling. The river and the sea barely register, and storm rain on the wrong street is what a buyer here should look up.