Only along the river, and that is a smaller part of town than the question suggests. Blandford is named for a fishing ford, which is the place admitting where the water goes. The high-probability river zone covers a strip of postcodes and then stops. One property in the whole area rates high risk from rivers, and it is not a home. Flooding here is an address question rather than a town question.
The Environment Agency's river-and-sea flood zones put around 7% of the area's postcodes in zone 3, the high-probability band, and around 1% in zone 2. Zone 2 being the smaller figure is not a misprint. The two are exclusive bands, with zone 2 the additional medium-probability fringe lying beyond zone 3 rather than a larger area containing it. Ten flood events sit on the Environment Agency's recorded register for the area, the most recent in December 1979, when a main river exceeded its channel capacity with no raised defences in place.
Surface water is the flooding that ignores the river map entirely. The town sits on chalk bedrock, with alluvium through the floodplain, head deposits around the southern and south-western edges and clay with flints at the highest ground in the north, which is why the answer changes street by street rather than neatly by distance from the Stour. The measure that captures surface water here is the postcode-level indicator set rather than the river zones.
On the climate-adjusted flood zone, which models where the high-probability boundary moves as rainfall and sea level change, none of the area's postcodes currently fall inside it. That is a zero produced by a model rather than a promise, and models get revised.
For insurance, the figure that matters is attached to the address, not the town. A property inside zone 3 will be asked about, can carry a flood-specific excess, and sometimes takes longer to place than the seller's timetable allows for. Get an indicative quote before instructing a solicitor rather than after, because the answer is cheap to obtain early and expensive to discover late.
Across all the flood indicators combined, including surface water, around 8% of the area's postcodes carry a high rating on at least one measure, around 12% a medium rating and around 31% a low rating. Those bands overlap with the river zones rather than sitting alongside them, so they cannot be added together. A postcode can appear in both counts for the same puddle.
Counted as homes rather than postcodes, the Environment Agency's rivers-and-sea mapping lists 1,086 properties across the 55 postcodes that carry any risk at all. Of those, one rates high, 76 medium, 609 low and 18 very low. None of the high-risk properties are residential. Postcodes with no risk do not appear on that list, so the total describes the exposed edge of the town rather than the town itself.
Whether anything stands between the water and the building is the question most flood summaries skip. Around 3% of the area's postcodes sit inside a modelled high-risk extent with no defence present in the model, against under 1% where a defence is present. Around 10% sit inside a modelled low-risk extent with nothing defending them. Defended is a modelling label meaning a structure exists in the calculation. It is not a statement that a property is safe, and reading it as reassurance is how people end up surprised.
The nearest tide gauge is at Portsmouth, where the record from 1962 to 2023 gives a measured rise of around 2 millimetres a year. That is a historic rate across six decades of readings rather than a forecast, and Blandford is an inland river town where the working mechanism is rainfall and channel capacity, not the sea. The gauge is background to the river's behaviour rather than a threat of its own.
Flood risk here sits squarely in the middle of the range: real along the water, absent across most of the town, and entirely knowable before anyone signs anything. Put the exact address into the Environment Agency's long-term flood-risk tool, and the town-level answer stops mattering.