Parts of it, and they are the parts you would guess. The harbour edge and the low ground behind it carry real risk. Most of the town sits outside the river and sea flood zones entirely. More than half the postcodes lie within a few hundred metres of open water, which is the whole appeal and the whole problem in one sentence. Penzance is not a flood town. It is a town with a flood edge, and the edge is where the views are.
Taking rivers and the sea first, the Environment Agency's mapping puts about 6 percent of the area's postcodes in flood zone 3, the higher-probability band, and under 1 percent in zone 2, the additional medium-probability fringe that sits beyond zone 3 rather than around it. Zone 2 being the smaller number is not an error; it is what a coastal town looks like when the risk comes from the sea rather than from a river spreading slowly across a floodplain. Under 1 percent of postcodes fall inside a historic flood outline, and three flood events are on the record, the most recent in October 2004, caused by the sea when channel capacity was exceeded with no raised defences present.
Surface water is a separate problem and does not appear in those zones at all. Rain that arrives faster than the drains can take it does not care about a flood zone boundary, and in a town built on a slope down to a harbour it collects at the bottom. The only measure here that folds surface water in alongside rivers and sea is the combined postcode indicator, which is set out further down.
Looking forward, the Environment Agency's climate allowance widens the picture to about 9 percent of postcodes inside the adjusted zone. That is the same map with the sea given room to do what it is already doing.
For insurance, this matters more than most buyers expect. A property inside a mapped zone can attract higher premiums, a larger excess specifically for flood, or conditions on cover, and the quote you get depends on the individual address rather than the town. Get an indicative quote before you instruct a solicitor, not after the survey comes back.
On the combined indicator, which counts a postcode as at risk if it rates on at least one measure including surface water, about 15 percent of postcodes rate high, 13 percent medium and 35 percent low. Those bands overlap with the flood zone figures rather than adding to them, because a single postcode can appear in both. They describe a different question: not whether the sea reaches you, but whether water of any kind does.
Counted as homes rather than postcodes, the Environment Agency's rivers and sea mapping lists 1,492 properties carrying some level of risk, of which 327 are high, 94 medium and 119 low. Of the high-risk properties, 239 are residential. Only postcodes carrying some risk appear in that list at all, so this is the affected slice of the town rather than the whole of it.
The defended question is the one most flood summaries skip. About 6 percent of postcodes sit inside a high-risk modelled extent with no defence present in the model, against about 4 percent where a defence is present. Present in the model means a structure exists in the mapping, not that the house behind it is safe, and not that the structure will hold in the storm that eventually tests it.
Proximity is the underlying fact. Around 54 percent of postcodes sit within 500 metres of the coast, which is a threshold the mapping uses rather than a statement about any one address, and the median distance to the water is about 457 metres. The closest postcode is effectively on the shoreline, a metre from it.
The shoreline management policy for the area is to hold the line across the 20, 50 and 100 year horizons. That is a stated intention to maintain defences, written by people who will not be around to be held to it. It is not a guarantee, and it is not a defence that already exists.
At the nearest tide gauge, at Devonport, sea level rose by about 2.35 millimetres a year across the record from 1962 to 2015. That is a measured historic rate over half a century, not a forecast, and it is the reason the climate-adjusted map is wider than the current one.
Flooding is one of the weaker parts of the case for Penzance, and the risk is concentrated rather than general. Check the individual address against the Environment Agency's long-term tool before you fall in love with the view, because in this town the view and the risk are frequently the same thing.