Checking a property's flood risk before you buy

Guide · 27 October 2026

Flooding is one of the few problems with a house that you cannot see on a sunny viewing day. A home that has flooded, or sits where water collects in heavy rain, can be harder to insure, harder to mortgage and harder to sell later. The good news is that a lot of flood information in the UK is public and free, and you can check most of it before you even make an offer. This guide explains the different kinds of flooding, the official maps, what insurers look at, how Flood Re works, and what to ask.

Four kinds of flooding

Flood risk is not one thing. The maps and the questions you ask depend on where the water would come from.

• Rivers: water spilling over the banks of a river or stream after prolonged or intense rain upstream.
• The sea: coastal flooding from high tides, storm surges and waves, often combined.
• Surface water: heavy rain that cannot soak away or drain fast enough, running over the ground and pooling in low spots. It can happen far from any river, including on hillsides and in towns, and it is a common cause of home flooding.
• Groundwater: the water table rising after long wet spells, usually in chalk and other permeable rock areas, sometimes coming up through floors and into cellars and staying for weeks.

Reservoir flooding is mapped too, but it only happens if a dam fails, which is very rare in the UK.

Flood zones explained

In England, the Environment Agency's Flood Map for Planning divides land into flood zones for rivers and the sea, ignoring defences:

• Flood Zone 1: low probability. Land with less than a 1 in 1,000 chance of flooding from rivers or the sea in any year.
• Flood Zone 2: medium probability. Between 1 in 100 and 1 in 1,000 for rivers, or between 1 in 200 and 1 in 1,000 for the sea.
• Flood Zone 3: high probability. A 1 in 100 or greater annual chance from rivers, or 1 in 200 or greater from the sea.

Flood zones are mainly used to decide planning applications, so they describe the land, not your particular house, and they leave out defences. That is why there is a second service, Check your long-term flood risk, which estimates the chance of flooding for an area taking defences into account, and shows surface water, reservoir and, where available, groundwater information alongside rivers and the sea. It usually rates areas from very low to high.

A "1 in 100" chance does not mean a flood once a century. It means a 1% chance in any given year, and a flood one year does not make one the next year less likely. Over a 25-year mortgage, small annual chances add up.

The other nations have their own maps. In Wales, Natural Resources Wales publishes flood risk maps and a Flood Map for Planning. In Scotland, SEPA publishes flood maps for rivers, the coast and surface water. In Northern Ireland, the Department for Infrastructure (DfI Rivers) publishes flood maps.

Why a house in a low-risk area can still flood

Maps are built from models at a broad scale. They cannot know about a blocked culvert behind the garden, a road that channels water to a front door, a basement, or a ground floor that sits lower than the pavement. Equally, a house shown at higher risk may have a raised floor, flood doors or a history of staying dry. Treat the maps as a reason to ask questions, not as a verdict.

When you view, look at the lie of the land. Is the house at the bottom of a slope, or below the level of the road? Is there a stream, ditch or culvert nearby? Are there airbricks low down on the walls, signs of tide marks or recent replastering at low level, or new flooring that seems out of place? Do the neighbours have flood barriers fitted?

What to ask the seller

In England and Wales, the seller fills in the Property Information Form (often called the TA6), which asks whether any part of the property has flooded, what type of flooding it was, and whether a flood risk report has been prepared. Read the answers carefully, and ask follow-up questions through your conveyancer, for example:

• When did it flood, how deep was the water, and which rooms were affected?
• Was an insurance claim made, and was the work done by a professional?
• Are there any flood resistance or resilience measures, such as flood doors, non-return valves or a pump, and are they maintained?
• Is the current buildings insurance through Flood Re, and what is the excess?

Estate agents are also expected to give material information about a property in their listings, and flood risk is part of that, so check the listing and ask the agent.

What insurers look at

Insurers use their own flood models, often at the level of individual addresses, as well as postcode data and their claims history. They usually ask whether the property has flooded before and may ask about its construction and flood measures. A previous flood or a high modelled risk can mean higher premiums, a bigger flood excess, or in some cases difficulty getting cover on the open market.

It is sensible to get a buildings insurance quote for the property before you exchange contracts, not after. If you have a mortgage, your lender will expect buildings cover to be in place from exchange or completion, depending on the contract, and a surprise at that stage can be expensive.

How Flood Re works

Flood Re is a scheme set up by the government and the insurance industry to make flood cover for homes more affordable. You do not apply to Flood Re yourself. Instead, your insurer can pass the flood part of your home insurance policy to Flood Re behind the scenes, and you buy the policy as normal. It covers many homes in the UK, but there are limits:

• it is for household insurance, not businesses;
• it does not cover homes built from 1 January 2009 onwards, because new building should take flood risk into account;
• some property types are excluded, such as certain larger blocks of flats, and there are other eligibility rules;
• it is designed as a transition and is due to end in 2039, with the aim that flood insurance prices then reflect risk.

Not every insurer offers policies that use Flood Re, so a specialist broker can help if you are struggling. Check the current rules on Flood Re's own website, as they can change.

The searches your conveyancer orders

A standard environmental search usually includes a flood section covering rivers, sea, surface water and groundwater. If it flags risk, your conveyancer may recommend a dedicated flood report. You can also ask the Environment Agency (or the equivalent body in Wales, Scotland or Northern Ireland) for the flood risk information they hold for a location, and the council's lead local flood authority may have records of past surface water flooding.

Flood risk is not always a deal breaker

Many homes in flood risk areas are bought and sold every year, and live safely. What matters is understanding the risk, being able to insure the property at a cost you can live with, and knowing what you would do if water came. Signing up for free flood warnings where they are available, knowing where to turn off gas and electricity, and keeping a simple flood plan can all reduce the damage if it happens.

This guide is general information, not legal, insurance or financial advice. Check current details with your conveyancer, insurer or broker.