Mostly no, and where the risk exists it is small and specific. Very few postcodes fall inside the river flood zones. Only a handful of homes rate high for river flooding. Surface water is the more common worry, and it is still a minority one. For a Chilterns village, the water mostly passes through.
On the Environment Agency's river-and-sea mapping, about 3% of Chalfont St Peter's postcodes fall in flood zone 2, and under half a percent fall in zone 3. The two zones do not overlap. Zone 3 is the higher-probability core, and zone 2 is the medium-probability fringe beyond it. The village's one recorded flood came in October 2001, when a main river overflowed its channel at a point with no raised defences.
Surface water is rain that cannot drain away fast enough, and the Environment Agency maps it separately from rivers. Here it is counted within the wider postcode indicators described below, and it accounts for most of the difference between those figures and the small river zones.
Under the Environment Agency's climate-change allowance, the share of postcodes in the modelled flood zone rises to about 5%. That figure shows how the mapped zone would grow under wetter conditions, and it puts no date on any flooding.
A home in one of those zones, or on a postcode with a high surface-water flag, can cost more to insure or attract a flood excess. The rest of the village should find flood cover unremarkable. The useful check is an indicative buildings insurance quote on the exact address early on, before paying for surveys, since the insurer's view is the one that sets the bill.
The wider postcode count takes in every indicator, surface water included. On that count about 4% of postcodes rate high on at least one measure, about 8% medium and about 23% low. These bands overlap with the river zones above and measure something broader, so the two sets of numbers should never be added together. Low is the band most postcodes with any flag at all fall into.
Counted as properties, the Environment Agency's rivers-and-sea mapping lists 397 homes and buildings in the 26 postcodes that carry any river risk at all. Three of them rate high, 20 medium and 257 low, and none of the high-risk properties is residential. Postcodes with no river risk are left off that list entirely, so the 397 is the at-risk group and the rest of the village sits outside it.
The defence question has a short answer here. About 0.4% of postcodes fall inside the high-probability extent when defences are left out of the model, and the same 0.4% fall inside it when they are put back in. In this part of the map the modelled defences make no difference, which fits a flood that came from a river with no raised banks. A "defended" label would only mean a defence appears in the model, which is weak protection even where one exists.
The nearest tide gauge is at Portsmouth, where the sea has risen at about 2 millimetres a year over its record from 1962 to 2023. That is a measured past rate on the south coast. The sea is a long drive from the nearest kitchen in Chalfont St Peter.
Flood risk is one of Chalfont St Peter's better features: a few homes need a careful look, and the rest of the village can spend its worry on the mortgage.