The house is 400 metres from a river you cannot see from the garden, the seller says it has "never flooded", and the estate agent has changed the subject twice. Flood risk is one of the few things about a house that is mapped and published by a government agency, so you do not have to take anyone's word for it. But there are three maps and they do not always agree.
What do flood zones 1, 2 and 3 mean?
The zones come from the Environment Agency's Flood Map for Planning and cover rivers and the sea only. Zone 1 is a chance of flooding below 1 in 1,000 in any year. Zone 2 is between 1 in 1,000 and 1 in 100 from rivers, or 1 in 1,000 to 1 in 200 from the sea. Zone 3 is 1 in 100 or greater from rivers, or 1 in 200 or greater from the sea, and 3b is the functional floodplain where water is meant to go.
The zones ignore flood defences. A house behind a well maintained embankment can sit in zone 3 and be fairly dry in practice, which is why the separate "risk of flooding from rivers and sea" layer, which does count defences, often tells a different story. Wales and Scotland have their own maps, from Natural Resources Wales and SEPA.
Why is surface water a separate map?
Because most flooding in England now comes from rain that cannot drain away, not rivers bursting. It hits houses at the bottom of a slope or on a road where the gullies block, and it does not show up in the flood zones at all.
The long term flood risk service has its own surface water layer, rated very low to high, and it is the one lenders and insurers increasingly ask about. Zone 1 with high surface water risk is a common and slightly confusing result.
Will I get insurance and a mortgage?
Flood Re is a government backed scheme that lets insurers offer affordable cover on homes built before 1 January 2009, whatever their flood risk. It ends in 2039, and later homes are not eligible, so a new build in zone 3 relies on the open market.
Most lenders will lend on zone 2 with a standard quote in hand; some want a flood risk report on zone 3. Ask the broker early.
What about sewage overflows?
Combined sewer overflows are the points where a water company is allowed to release untreated sewage into a river or the sea when the network is full, usually after heavy rain. Since 2023 every overflow in England has had Event Duration Monitoring fitted, and the companies publish how often each one spilled and for how long.
This matters if the house backs onto a river or is near a beach you plan to swim from, and a sewer that spills often is a sewer that is often full.
Who looks after the stream at the bottom of the garden?
If a watercourse runs through or along the boundary, you are probably the riparian owner: you own the bed to the centre line and must keep it clear, culvert under the drive included. The lead local flood authority (usually the county council) can require maintenance, so look at the banks.
What should I ask?
Ask the seller, through your solicitor, the flooding question on the TA6 form and then ask again in person: "Has the house, the garden or the road flooded while you have lived here, and did you claim?" Ask your solicitor: "Which flood zone is the property in, what does the surface water map say, and is there a watercourse on the title plan?" And ask the neighbours, who remember 2007 and 2014 better than any map.
How Eavesdrop checks this
Eavesdrop reads the Environment Agency flood zones, the risk of flooding from rivers and sea layer, the surface water map, the historic flood outlines, and the water company's Event Duration Monitoring returns for the nearest overflow, then cites each one. Start with [check: flood-risk]. Before you offer. Before you sign. Eavesdrop.
Quick answers
What does flood zone 2 mean? Flood zone 2 means a 1 in 1,000 to 1 in 100 chance of river flooding in any year, or 1 in 1,000 to 1 in 200 from the sea, ignoring defences.
Can I get insurance on a house in a flood zone? Usually yes. Flood Re lets insurers offer affordable cover on homes built before 2009 regardless of flood risk, until the scheme ends in 2039.
How do I check flood risk by postcode? Use the Environment Agency's "check the long term flood risk" service for England, which shows river, sea and surface water risk for any postcode.
Sources: Environment Agency Flood Map for Planning and long term flood risk service; Flood Re scheme guidance; Environment Agency Event Duration Monitoring storm overflow data; Law Society TA6 Property Information Form.
