Some of it, and the some is predictable. The water is at the end of most streets. Around one postcode in ten carries a high rating on at least one flood measure. The rest of the town climbs a hill and sits well clear of the question. Flood risk here is a question about which door you buy, not about the town.
Start with rivers and the sea, which the Environment Agency maps as exclusive zones. About 6% of Newlyn's postcodes fall inside flood zone 3, the higher-probability band, and about 3% fall inside zone 2, the medium-probability fringe that sits beyond zone 3 rather than containing it. Zone 2 being the smaller figure is a feature of how the bands are drawn, not an error. Anywhere else on this site that a surface-water number appears, it comes from a different indicator and should not be read against these.
Surface water is not mapped here as a separate zone, so it arrives folded into the combined postcode indicator below rather than standing on its own. The recorded history is more concrete: 11 flood events are on the register for this area, the most recent in November 2012, logged as coming from the sea with channel capacity exceeded and no raised defences in place. Historic flood extents cover about 4% of postcodes.
Looking forward, the climate-change allowance widens the picture considerably. Once that allowance is applied, about 14% of postcodes fall inside the mapped zone, against 6% in zone 3 today. That is the number a buyer planning to still be here in thirty years should be reading, rather than the current one.
For insurance, the practical consequence is that address-level risk drives the quote, and in a town with this split the difference between two houses a hundred metres apart can be substantial. Anyone buying near the harbour should get an indicative buildings quote before instructing a solicitor rather than after, and should ask specifically whether flood cover is included or excluded rather than assuming a headline premium covers it.
Taking all measures together, including surface water, about 11% of Newlyn's postcodes rate high on at least one indicator, about 14% medium and about 40% low. Those bands overlap with the river-and-sea zone figures rather than adding to them; a postcode can appear in both, and reading the two sets as cumulative produces a town that does not exist.
Counted as homes rather than postcodes, the Environment Agency's rivers-and-sea mapping puts 63 properties at high risk, 38 at medium, 65 at low and 77 at very low, out of 469 properties across the 31 postcodes that carry any risk at all. Of the high-risk properties, 23 are residential. Postcodes with no modelled risk do not appear in that count, which is why the total is a fraction of the town.
On whether anything stands between the water and the building, about 6% of postcodes sit within a high-risk extent with no defence present in the model, against about 4% where a defence is present. A modelled defence is not a guarantee of dry floors. It is an asset that exists, with a design standard it can be exceeded, and it should be treated as a fact about the model rather than as reassurance.
The coast is close by any measure. About 89% of postcodes sit within 500 metres of it, which is a threshold the mapping defines rather than a claim about any particular address, and the typical postcode is around 160 metres away. The closest sits 8 metres from the water.
Every postcode here is covered by a shoreline management plan, and the stated policy across the twenty, fifty and hundred-year horizons is to hold the line, meaning maintain the existing coastal defence position. That is an intention held by public bodies over those horizons, subject to funding and review, rather than a promise or a defence that already exists everywhere the policy applies.
At the nearest long-record tide gauge, at Devonport, sea level rose by about 2.35 millimetres a year across the 1962 to 2015 record. That is a measured historic rate at that gauge, not a projection for this coast.
Flood risk in Newlyn lands somewhere in the middle: real and concentrated at the bottom of the hill, close to irrelevant at the top, and the sort of thing that rewards checking the exact address instead of the town name.