Yes, in parts, and the parts are what matter. Roughly one postcode in ten sits in the highest river flood zone. Most of the town sits clear of it altogether. The river has previous, and the modelling shows nothing standing between it and the houses. Whether Cullompton floods is the wrong question; whether your street does is the right one, and the answer changes at the end of the road.
The Environment Agency's river-and-sea mapping puts about 10% of the town's postcodes in flood zone 3, the highest-probability band, and about 3% in flood zone 2. Those two are separate rings rather than one inside the other: zone 2 is the extra fringe of medium probability sitting beyond zone 3, which is why it can be the smaller of the two and why adding them together tells you nothing useful.
Surface water is not published here as its own share. It is folded into the combined postcode indicator further down, so anyone hunting for a standalone drainage figure will not find one. What the record does carry is history: 37 flood events on file for the area, about 6% of postcodes with a recorded historic flood, and a most recent entry from August 1997 when the main river exceeded its channel capacity with no raised defences involved.
The climate-adjusted mapping, which stretches the zones to allow for future conditions, currently brings no additional postcodes into the extent. That is a model output rather than a promise, and models get rerun.
For insurance, the practical effect is that Cullompton has no single answer. An address inside zone 3 will be quoted differently from one three streets away, and some insurers price the postcode rather than the property, which cuts both ways depending on which side of the line you sit. Get an indicative quote on the specific address before instructing a solicitor, not after the survey comes back and everyone is emotionally committed.
Across all measures together, including surface water, about 14% of the town's postcodes carry a high rating on at least one indicator, 17% a medium and 24% a low. Those bands overlap with the river-and-sea zone figures and describe the same ground counted a different way, so they are an alternative view rather than an addition to it.
Counted as buildings instead, the Environment Agency's rivers-and-sea mapping records 1,250 properties across the 53 postcodes that carry any risk at all. Of those, 181 sit at high risk, 429 at medium and 33 at low, with 95 of the high-risk properties residential. Postcodes with no risk do not appear in that list, so the total is the exposed part of the town rather than the whole of it.
On the question of whether anything protects them: about 11% of postcodes fall inside the high-risk extent with no defence present in the model, against none inside a defended one. The undefended reading is what the mapping shows today. Even where a defence does appear in a model, it describes a structure's presence, not a guarantee about any particular house.
The nearest tide gauge is at Devonport, which over its 1962 to 2015 record measured sea level rising at about 2.35 millimetres a year. That is a historic rate from a coastal instrument some distance away, and this town's water arrives down the Culm rather than up the estuary, so treat it as background rather than the local threat.
Flood risk here lands in the middle: not a town to strike off the list, not one to buy in blind. A tenth of it sits in the highest river zone with nothing modelled in the way, and the other nine-tenths will never think about it.