Yes, and Boscastle has fewer illusions about it than most places do. Around one postcode in seven carries a high rating on at least one flood measure. Nearly half the village sits within a few hundred metres of the sea. Seven flood events are on the record, and the valley funnels two rivers into one harbour mouth. The risk is real, it is concentrated, and it is also the reason the village looks the way it does.
Taking rivers and sea first, the Environment Agency's flood zones cover about 8% of the area's postcodes in zone 3, the highest-probability band, with a further 6% in zone 2, the medium-probability fringe that sits beyond zone 3 rather than around it. That is the mapped river and sea picture only. It is a different measure from the surface-water indicators, and mixing the two produces a number that means nothing.
Surface water is the part the zones handle least well and the part that did the damage here. The recorded cause of the most recent event, in August 2004, was channel capacity being exceeded on a main river with no raised defences behind it, which is what happens when steep ground, thin soil over slate and two watercourses meeting at a harbour all agree to cooperate on the same afternoon. The postcode indicators used later in this answer fold surface water in alongside rivers and sea, because for a valley like this one the distinction matters less to a kitchen floor than it does to a map.
Looking forward, the Environment Agency's climate change allowance lifts the share of postcodes inside the flood zones to about 14%. That is a modelled extent under a future climate scenario rather than a forecast for any particular year, but it is the number a lender's valuer and a long-term buyer should both be working from.
For insurance, expect the question to come up and expect the answer to depend on the exact address rather than the village. Get an indicative buildings quote before instructing a solicitor, ask the current owner for the property's claims history, and read any exclusion for flood carefully, because a policy that covers the building but excludes the thing most likely to damage it is not cover.
On the broader postcode picture, which counts a postcode if it rates on at least one flood measure including surface water, about 14% rate high, 22% medium and 39% low. Those bands overlap with the zone shares above rather than adding to them. Roughly 14% of postcodes also fall within recorded historic flood extents, which for this village is less a statistical curiosity than a memory.
Counted as homes rather than postcodes, the Environment Agency's rivers-and-sea mapping puts 156 properties in the nine postcodes that carry any risk at all, of which 8 are at high risk and 92 at medium. Three of those high-risk properties are residential. Postcodes with no risk do not appear in that count at all, so this is the exposed end of the village described in full, not the village as a whole.
On whether anything stands between the water and the buildings, about 8% of postcodes sit inside a modelled high-risk extent with no defence present, and about 8% sit inside a high-risk extent where a defence does appear in the model. A defence appearing in a model is not a guarantee of dry floors. It means the modelling accounts for a structure, not that the structure will hold in the event that matters.
The sea is close. About 47% of postcodes lie within 500 metres of the coast, which is a threshold the mapping defines rather than a claim about any one house, and the median distance to the water across the area is roughly 520 metres. The closest postcode sits about 22 metres from the coast.
Every postcode here falls under a shoreline management plan, and the stated policy at the twenty, fifty and hundred year horizons is to hold the line. That is an intention to maintain defences over those timeframes, subject to future funding decisions, and not a promise or a description of what exists on the ground today. Separately, the nearest long-record tide gauge at Devonport measured sea level rising at about 2.35 millimetres a year across its 1962 to 2015 record, which is a historic measurement rather than a projection.
Boscastle's flood position is middling rather than alarming, which will surprise anyone who only knows the village from the helicopter footage. The exposure is genuine but tightly drawn around the valley floor and the harbour, and the address matters far more here than the postcode does.