Not much, and what risk exists arrives from the sky rather than up a river. Almost none of the town sits in the mapped river-and-sea flood zones. Twelve properties carry a high rating, and they cluster in a few postcodes rather than spreading across the place. Surface water is the mechanism that actually matters here. For a town this close to the water, there is remarkably little to declare.
The Environment Agency's river-and-sea mapping places about 1% of Northam's postcodes in flood zone 3, the highest-probability band, and none at all in flood zone 2. Those two zones are separate bands rather than one nested inside the other. Zone 2 is the medium-probability fringe lying beyond zone 3, so the smaller zone 2 figure is not a contradiction: it means the fringe barely extends past the core.
That leaves surface water as the realistic route to a wet carpet. Water in a town shaped like this one comes off roofs, roads and slopes rather than out of a channel, and the postcode indicators further down fold that source in alongside rivers and sea.
Adding the climate allowance barely shifts anything. About 1% of postcodes sit inside the climate-adjusted zone, which is the same share as the mapping shows today. The forward view and the present view agree, which is not something the flood pages of most coastal towns can say.
For insurance, that combination is workable rather than alarming. A property outside the mapped zones is usually quoted as normal, while one inside them, or one with a history of water coming in, can attract a higher excess and more questions on the proposal form. Get an indicative quote for the exact address before instructing a solicitor, because the postcode answer and the address answer are two different documents.
On the broader postcode indicators, which rate each postcode against at least one flood measure and include surface water, about 11% of Northam postcodes rate high, about 14% medium and about 31% low. Those bands overlap the zone figures rather than adding to them, and a count of postcodes is not a count of homes.
Counted as homes, the Environment Agency's rivers-and-sea mapping covers 126 properties across the five postcodes here that carry any risk at all. Of those, 12 are rated high, 9 of them residential, while 9 are low and 1 is very low, with none sitting in the medium band. Postcodes with no risk never appear on that list, so 126 describes the exposed edge of the town rather than the town.
Whether anything stands between the water and the building is the question flood summaries tend to leave out. About 1% of postcodes fall inside a modelled high-risk extent with no defence present in the model, and a smaller share, rounding to about the same, fall inside a high-risk extent where a defence is present. Present in the model means a structure exists in the modelling. It does not mean the structure is adequate, maintained, or standing between any particular house and the sea.
The water is close. Roughly 7% of postcodes sit within half a kilometre of the coast, which is a threshold the mapping uses rather than a statement about any one address, and the nearest postcode is about 82 metres from it. The median distance across the town is about 930 metres, so most of Northam watches the sea from a sensible step back.
Every postcode here falls under a shoreline management plan, and across the twenty-year, fifty-year and hundred-year horizons the policy is hold the line: a stated intention to maintain the existing defence position. An intention is not a guarantee, and it is not a wall. It is a planning position that future funding decisions are free to revisit.
The nearest long-record tide gauge, at Devonport, measured sea level rising about 2.35 millimetres a year across its record from 1962 to 2015. That is a measured historic rate over those years, not a projection of the next fifty.
No flooding appears in the area's historic flood record. That is genuinely reassuring, and it deserves to be read precisely: nothing has been logged, which is not the same as nothing ever having come up a drain on a bad November night.
Flood risk here sits mid-table. A small and identifiable set of properties carry real exposure and should be checked address by address, while everyone else is buying the ordinary amount of coastal weather.