Cam's flood risk comes mostly from rain, and much less from rivers. The river-and-sea flood zones cover under one postcode in a hundred. Count surface water as well, and about one postcode in fourteen rates high. Only a handful of homes are rated high for river flooding. For most of Cam, a heavy downpour is a bigger worry than a river rising.
On the Environment Agency's river-and-sea mapping, under 1% of Cam's postcodes fall in Flood Zone 3, the highest-probability band, and under 1% in Flood Zone 2, the medium-probability fringe outside it. The two bands are separate and both cover very little. The Agency has two recorded floods on file for the area. The latest was in July 1968, when the main river ran over its channel with no raised defences in the way.
Surface water is a different measure from river and sea flooding, and in Cam it matters more. It is rain that has nowhere to go: it pools at the bottom of a slope or backs up where the drains give out. It does not follow the river corridor, so a house can be well away from any watercourse and still sit on a wet patch.
The Environment Agency's climate-adjusted mapping, which looks ahead to a wetter future, puts about 1% of postcodes in the flood zone. That is a modelled scenario for the decades to come, and on this measure Cam's river exposure stays small.
For most homes in Cam, the river-and-sea numbers should not trouble an insurer. The exceptions are the few postcodes inside the zones and any street with a surface-water flag, where cover may cost more or come with more questions. Get an indicative insurance quote on the exact address early, and look up its surface-water rating on the Environment Agency's long-term flood risk service while you're at it. The quote will show how the insurer reads that particular street.
Postcode by postcode, about 7% rate high on at least one of several flood measures, with surface water counted alongside rivers and sea. Another 11% rate medium on at least one, and about 33% rate low. One flag on any of those measures is enough to put a postcode in a band, which is why these shares are larger than the river-only zones.
Counted as homes, the river-and-sea picture shrinks to a short list. The Environment Agency lists 12 postcodes in Cam with some river or sea risk, covering 254 properties. Of those, eight are rated high, six medium and 17 low, and only one of the eight high-rated properties is residential. Postcodes with no river or sea risk don't appear in that count at all. So for most buyers, Cam's river risk comes down to a single house.
Whether anything holds the water back makes little difference to Cam's figures. Under 1% of postcodes fall in the high-probability extent with defences left out of the model, and the same small share with them included. "Defended" here only means a defence appears in the model. It says nothing about whether a given house stays dry.
Cam's nearest point is about 4.5 kilometres from the coast, and the median postcode about 6 kilometres, yet every postcode falls under a shoreline management plan. For the next 20 years the plan's policy is managed realignment, which means letting the shoreline move back in a controlled way. For the 50- and 100-year horizons the policy is to hold the line. These are intentions for those periods. They depend on money nobody has committed yet, and they say nothing about what defences stand on the shore today.
The nearest tide gauge with a long record is at Portsmouth. It measured sea level rising by about 2 millimetres a year between 1962 and 2023. That is a past rate from one gauge, and Cam is a long way inland from it.
Flood risk is middling in Cam. The river barely registers. Surface-water risk varies from street to street, so it is worth looking up before choosing a house.