Dunstable does have a flood problem, though rivers and the sea play no part in it. None of the town falls in the river-and-sea flood zones. Even so, more than a third of its postcodes rate high on at least one flood measure. No past flooding is on record here. The risk in Dunstable comes down as rain.
On the Environment Agency's river-and-sea mapping, 0% of Dunstable's postcodes are in Flood Zone 3, the highest-probability band, and 0% are in Flood Zone 2, the medium-probability band beyond it. Neither zone touches the town. A buyer who checks only the river map will come away thinking Dunstable is dry.
Surface water is a different matter. It is what happens when heavy rain arrives faster than the ground and the drains can take it, and in Dunstable it is the main risk once river and sea are ruled out. Surface water is mapped separately from the flood zones and it gets no mention on the river map. It shows up in the postcode-level measures described further down this page.
On the Environment Agency's climate-adjusted mapping, which redraws the river-and-sea zones for future conditions, 0% of Dunstable's postcodes fall inside. The forward look on rivers and sea is as clean as the current one.
Insurers price surface water risk address by address, and they do not care that the river map is blank. Two houses on the same Dunstable estate can get noticeably different quotes because one sits lower than the other or near a drain that backs up. The Environment Agency's long-term flood risk service lets anyone enter an exact address and see its surface water rating. It is worth looking that up for any house you are seriously considering, and getting an indicative insurance quote at the same time.
The postcode-level measures combine several kinds of flooding, surface water included, and count a postcode if it rates on any one of them. On those measures about 36% of Dunstable's postcodes rate high on at least one, 23% rate medium on at least one, and 42% rate low on at least one. A postcode can appear in more than one band because it can score differently on different measures. With river and sea flooding absent, those high ratings come from the other measures.
The Environment Agency's modelled flood extents put 0% of Dunstable's postcodes in a high-risk area with defences and 0% in one without. No river or sea extent reaches the town, so the model shows no defence because there is nothing for one to hold back. A river wall is no help with surface water anyway. A house that floods from the road needs good drainage and a raised threshold.
The nearest tide gauge to Dunstable is at Portsmouth. It recorded sea level rising by about 2 millimetres a year between 1962 and 2023. That is the rate measured on the south coast over those years. Dunstable is a long way inland, so that is as much bearing as the sea has on the town.
The Environment Agency's records show no past flooding anywhere in Dunstable. That is reassuring, but it only means no flood was recorded. A garage or driveway that took water in a downpour is unlikely to have made it into a national dataset.
On flooding, Dunstable comes out poorly. The river map is clean, but more than a third of its postcodes rate high for flooding from other sources, and that is where a buyer's risk lies.