Yes, in parts, and the parts are the ones beside the river. About one postcode in ten is in the highest river flood zone. Around one in eight carries a high rating on at least one flood measure. The Thames has flooded the village before. Most of Cookham stays dry, but the homes that flood tend to be the ones people moved here for.
The Environment Agency maps river and sea flood risk in zones, and the zones don't overlap. About 10% of Cookham's postcodes are in Zone 3, the highest-probability band. Another 10% are in Zone 2, the medium-probability ring outside it. These shares count postcodes and cover rivers and sea only. Odney, Formosa and Sashes are islands, which shows how little attention the Thames pays to property lines.
Surface water doesn't get its own share here. It is folded into the postcode indicators below. What there is instead is a history. About 12% of Cookham's postcodes have recorded flooding in the past, and the Environment Agency lists 32 recorded flood events. The most recent was in January 2003, when the main river overflowed its channel at a spot with no raised defences.
Allowing for climate change, the Environment Agency's adjusted zone covers about 20% of postcodes. That is how far the modelled flood area reaches once future rainfall and river flows are built in. It describes the model, and it doesn't predict that any particular winter will reach that line.
Insurers price flood cover address by address. A house in or near the Thames zones can mean a higher premium, a larger excess, or fewer insurers willing to quote. Get a quote for the exact address while you are still booking the survey, because how quickly insurers respond is useful information in itself.
The postcode indicators combine rivers, sea and surface water, and each postcode is counted at the worst rating it gets on any of them. On that basis about 13% of postcodes rate high on at least one measure, 23% medium and 29% low. These bands overlap with the flood zones above. They measure something different, so don't add them to the zone figures.
Counting homes gives a clearer picture than counting postcodes. The Environment Agency's rivers-and-sea mapping lists 707 properties in the Cookham postcodes that carry any risk at all, and postcodes with no risk aren't listed. Of those 707, 55 are at high risk, 121 at medium, 237 at low and 115 at very low. Twenty-two of the high-risk properties are homes.
There is also the question of what stands between the river and the house. In the Environment Agency's model, about 10% of postcodes fall inside the high-risk extent without defences and about 5% inside it with defences. "Defended" means a defence appears in the model, and that doesn't make any house safe. In January 2003 the water came over where there were no raised defences, and that is the version of events to keep in mind.
The nearest tide gauge to Cookham is at Portsmouth, which recorded sea level rising by about 2 millimetres a year between 1962 and 2023. That is the rate measured there over those years, and Cookham is a long way inland. The sea is someone else's problem. The Thames belongs to Cookham.
Cookham's flood risk is middling: serious for the minority of homes beside the Thames, and much lower everywhere further from the water.