Yes, Tewkesbury floods. It stands where the Severn meets the Avon, and parts of the town have flooded within living memory. About one postcode in six is in the outer river flood zone. Hundreds of homes are classed as high risk. Most of the town is on higher ground, but the low streets are a different matter.
The Environment Agency puts about 16% of Tewkesbury's postcodes in flood zone 2 and about 3% in flood zone 3. Those are the river-and-sea zones, and they do not overlap. Zone 3 is the highest-probability land, and zone 2 is the wider medium-probability fringe outside it. The Agency's records list 488 recorded flood events for the area. The most recent was in July 2007, from a main river. The flood plain is also why the town has not sprawled. On the old town's side of the motorway, the water has done more than any planning policy to keep the edges where they are.
There is no separate surface-water figure for Tewkesbury in the Agency's zone mapping, because those zones count rivers and the sea only. Rain that collects on hard ground before reaching any river is picked up by the postcode measure further down. A house outside both river zones can still have a drainage problem.
The Agency's climate-change version of the flood zones takes in about 27% of postcodes. It is the Agency's model of a wetter future, not a measured event, and it shows the flood-prone edge of the town extending further.
Insurance is where the risk becomes a cost. Homes in or near the flood zones can face higher premiums, larger excesses or a short list of insurers willing to quote, and a house that has made a flood claim can carry that history into every renewal. Ask the seller in writing whether the house flooded in July 2007, whether a claim was made, and whether any flood-resistance work was done afterwards. Those three answers will tell you more about the insurance than the age of the boiler.
The postcode-level picture combines several flood indicators, rivers and surface water among them. On that basis about 18% of Tewkesbury's postcodes are high risk on at least one indicator, about 20% medium and about 42% low. A postcode only needs to trigger one measure to be counted, which is why these shares are larger than the river zones alone.
Counted as properties, the Environment Agency's river-and-sea mapping lists 2,464 properties in postcodes with some risk. Of those, 226 are at high risk, 78 at medium and 749 at low, and 186 of the high-risk properties are homes. Postcodes with no river-and-sea risk at all are left out of that list, so it covers only part of the town. A count of 226 high-risk properties is more useful to a buyer than a percentage, because each one is a front door.
About 3% of postcodes are inside the modelled high-probability flood extent with no defence in the model, and about 3% are inside it with a defence present. "Defended" here means only that a wall or embankment appears in the Agency's model. It does not tell you how high the defence is, who maintains it, or whether the water has been over it before.
Postcodes here are covered by a shoreline management plan, with the nearest coast about 5.5 kilometres away at its closest. For that coast, the plan's policy is to hold the line over the next 20, 50 and 100 years. That is a stated intention to keep the shoreline where it is. The money to do it has not been committed, and the policy says nothing about which defences exist there now.
The nearest tide gauge in the national record is at Portsmouth, where sea level rose by about 2 millimetres a year between 1962 and 2023. That is a past rate from a gauge on another coast. In Tewkesbury, the rivers are the real concern.
Flood risk is Tewkesbury's weak point. A buyer here needs to check the history of the exact house as well as its price, because the riverside stretch and the higher ground carry very different risks.