Parts of it, and the parts you would guess. Bath sits in a bowl with a river through the middle, which is a lovely thing to look at and a specific thing to check before exchange. Around one postcode in ten carries a high rating on at least one flood measure. Around one in ten has a recorded flood event in its history. The city is not a flood plain, but the valley floor is, and the difference between the two is about thirty metres of elevation.
On the Environment Agency's river-and-sea flood zones, around 6% of the area's postcodes fall in zone 3 and around 7% in zone 2. Those bands are exclusive rather than nested: zone 2 is the additional medium-probability fringe sitting beyond zone 3, not a wrapper around it. Between them they trace the Avon through the valley, which is why the shares are modest for the area as a whole and highly concentrated once you look at where.
Surface water is the other half of the story and behaves differently. On the Environment Agency's postcode-level indicators, which fold surface water in alongside rivers and sea, around 11% of postcodes rate high on at least one measure, around 17% medium and around 36% low. Those bands overlap the zone figures rather than adding to them. In a city on limestone slopes, water arriving off the hill matters as much as water rising off the river, and a house nowhere near the Avon can still take a wet garage in a summer downpour.
Looking forward, the Environment Agency's climate-adjusted mapping puts around 1% of postcodes in a flood zone that expands under future scenarios. That is a small increment on top of an already-mapped picture rather than a redrawing of it.
For insurance, the practical consequence is boring and expensive. Properties inside the mapped zones will attract higher premiums, higher excesses on escape-of-water and flood cover, or questions the insurer wants answered before quoting. Anyone buying should get an indicative quote for the specific address before instructing a solicitor, because the difference between two houses on the same street can be substantial.
In property terms, the Environment Agency's rivers-and-sea mapping counts around 9,700 properties across the postcodes that carry any risk at all, with 632 at high risk, around 3,050 at medium and around 3,340 at low. Of the high-risk properties, 488 are residential. Postcodes with no risk do not appear in that list, so those counts describe the exposed part of the city rather than the whole of it.
On whether anything stands between the water and the building, around 7% of the area's postcodes sit inside a high-probability flood extent with no defence present in the model, against around 4% where a defence is present. Defended in this context means a defence exists in the modelling, not that the property is safe: defences have a design standard, water occasionally exceeds it, and the Environment Agency's own record of past events here includes overtopping of defences as a recorded cause. The most recent recorded event in the area dates to November 2012, on a main river, from exactly that cause. There are 371 recorded flood events in the area's history.
The nearest long-record tide gauge, at Portsmouth, shows a measured rise of around 2 millimetres a year across its 1962 to 2023 record. That is a historic measurement rather than a forecast, and Bath is inland, so it matters here as background rather than as a direct threat.
Flood risk in Bath is a middling picture that averages badly. Most of the city is fine and a defined minority of it is not, so the area-wide number is close to useless and the address-level check is close to essential. Put the exact postcode into the Environment Agency's long-term flood risk service before you fall in love with the kitchen.