Potton carries a modest flood risk, and very little of it comes from the brook through the middle of the parish. The river-and-sea flood zones barely touch the town. No flooding is on record. A broader measure that counts every source of water finds more, spread in small patches. Most of the risk here sits off the map that buyers usually check first.
On the Environment Agency's river-and-sea mapping, about 1% of Potton's postcodes are in Flood Zone 2, the medium-probability band, and none are in Flood Zone 3, the high-probability band. Zone 2 is the fringe that lies outside Zone 3, so here it covers a sliver of town with no high-probability core inside it. The Environment Agency's count of individual properties at risk from rivers and the sea lists none at high risk, 3 at medium and 48 at low, all within the five postcodes that register any risk at all. Potton Brook gave the parish its central valley, and on the official river maps it does very little else.
Surface water is a different matter, and the ground explains why. The town was built on sandy, freely draining soil to the west, while the land beside Potton Brook has naturally high groundwater and a peaty texture. About 9% of postcodes fall inside the Bedfordshire and River Ivel Internal Drainage Board's district, the body that manages water levels in the low-lying land. Heavy rain that the sand soaks up on one side of town has fewer places to go on the other.
The Environment Agency's climate-adjusted flood zone, which looks ahead to wetter conditions, takes in about 1% of postcodes, the same share as Flood Zone 2 today. On the river-and-sea measure, the extra rainfall projected for the coming decades barely moves the line in Potton.
For most homes in Potton, flood cover should be an ordinary part of a buildings policy. The exceptions are the handful of properties on the river mapping and the patches that show up for surface water, where an insurer may ask more questions or quote more. Put the exact address through an insurer for a quote early, because a premium is the quickest way to learn what the underwriter's map says about that one house.
Across all the measures combined, about 7% of Potton's postcodes rate high on at least one flood indicator, 16% medium and 40% low. That measure counts a postcode if any one of several sources, surface water included, puts it in the band, which is why it reads so differently from the river zones above. "Not in a flood zone" is true for nearly every house in Potton, and it answers only the river question.
On the defence question, the Environment Agency's modelled flood extents put none of Potton's postcodes in the high-probability area, either with defences or without them, and about 1% in the low-probability extent with no defence present. Nothing needs defending on that measure, because the modelled river water does not reach far enough. A defence in the model would not have meant a dry house anyway, and here the question does not come up.
The Environment Agency holds no record of historic flooding in Potton. That is a reassuring blank, though a blank in a register means nothing was recorded, and small surface-water floods are the kind that often go unreported.
Potton's flood risk is middling: the brook leaves the town alone, and the rain still marks out enough patches to make the individual address the thing to check.