Ashchurch has more flood risk than its river map suggests. Almost none of it is in the river-and-sea flood zones. Nearly a quarter of postcodes still rate high on at least one flood measure. The sea is miles away. Rivers are the small part of this question and rain is the big one.
On the Environment Agency's river-and-sea flood zones, 3% of Ashchurch postcodes fall in zone 2, the medium-probability band, and none fall in zone 3, the high-probability band. The two zones are separate bands, so zone 2 is the fringe beyond zone 3 and doesn't include it. By that measure, the rivers barely touch the village.
The trouble shows up on the measures that include surface water. Rain that lands on hard surfaces and can't drain away fast enough never shows up on a river map, and in a village where 23% of homes went up between 2000 and 2008, a lot of the ground is roofs, drives and roads. Where the river-and-sea zones are close to empty and the wider indicators are not, the water is coming from the sky.
Under the Environment Agency's climate allowance, the share of Ashchurch postcodes in the flood zones stays at about 3%. That's a modelled view of how the zones could grow as the climate changes, and on that model the rivers don't creep much further in.
Insurers price from the full picture, and that includes surface water. A home outside every river zone can still be quoted as a flood risk if surface water is mapped across the plot. The Environment Agency's long-term flood risk service shows surface water and river risk separately for each address, and an insurance quote on the exact house will tell you whether that matters more cheaply than the first wet winter will.
Across the measures folded together, 23% of Ashchurch postcodes rate high on at least one of them, 23% rate medium on at least one, and 37% rate low on at least one. A postcode only needs one measure to count, so these shares overlap with each other and can't be added up. They cast a wider net than the river zones, which is why the numbers are so much bigger.
The Environment Agency's modelled flood extents put 0% of Ashchurch postcodes in the high-risk river-and-sea extent, with or without defences. Where a defence does appear in that model, it means a structure exists. It doesn't mean the house is safe. Here the question barely arises, because the modelled river water doesn't reach the postcodes in the first place.
About a quarter of Ashchurch postcodes fall under a shoreline management plan, though the nearest coast is about 10 kilometres away. The policy is to hold the line at the 20, 50 and 100-year horizons. That's a statement of intent for the shoreline, and it depends on funding nobody has yet committed. It says nothing about the defences standing there today.
The nearest tide gauge in the record is at Portsmouth, where sea level rose by about 2 millimetres a year between 1962 and 2023. That's the rate measured at that gauge over those years. That the nearest gauge is on the south coast tells you how little the sea has to do with Ashchurch.
The Environment Agency's historic flood records show no recorded flooding across Ashchurch's postcodes. That's a good sign, but a record only shows what someone measured and mapped, and the absence of an entry isn't proof that no water ever came through.
The rivers stay away and the rain doesn't, so Ashchurch's flood risk is worse than its flood zones claim. It's one of the village's weaker points, and it varies from plot to plot more than from one end of the village to the other.