How to check a home’s flood risk before you buy

Look up the long term flood risk on GOV.UK in England or on Natural Resources Wales’ map in Wales, then ask the seller, your conveyancer and an insurer about the home itself. The official maps describe the risk to an area, not a promise about one building.

Checked 16 Oct 2026

The kinds of flooding to check

Flooding has different causes, and a home can be at low risk from one and higher risk from another. The official services show each one separately, so check them all.

Rivers and the sea: water spilling over river banks or coastal defences, often after long spells of rain or during storms and high tides.
Surface water: heavy rain that cannot drain away fast enough and runs across the ground or collects in low spots. It can happen far from any river, and in England more properties are at risk from surface water than from rivers and the sea.
Groundwater: water rising up through the ground when the water table is high, most often in chalk and limestone areas. It tends to rise slowly and can last for weeks.

The services also show the area that could flood if a large reservoir failed. That is extremely unlikely, because reservoirs are inspected and maintained under strict rules.

Where to look it up

In England

The Environment Agency’s long term flood risk service gives the risk from rivers and the sea, surface water and reservoirs for an area, and from groundwater where data is available. It also shows how climate change might increase the chance of flooding there. It places each area in one of four bands:

High: a chance of more than 3.3% each year (about 1 in 30).
Medium: between 1% and 3.3% each year.
Low: between 0.1% and 1% each year.
Very low: less than 0.1% each year (less than 1 in 1,000).

A 1% chance a year sounds small, but over a 25-year mortgage it adds up to more than a one in five chance of at least one flood.

In Wales

Natural Resources Wales publishes the Flood Risk Assessment Wales map. It shows the risk from rivers, the sea, surface water and small watercourses, and reservoirs, using similar high, medium, low and very low bands, along with flood defences and the areas they protect.

Both services describe an area, not a single building. A home on raised ground, or with its floors well above the street, can be safer than its band suggests; a basement flat can be worse.

What a flood risk area or flood zone means

You will meet several similar terms while buying, and they are not the same thing.

Flood risk bands (high to very low) come from the long term flood risk services above. They take account of flood defences and describe the chance of flooding each year.
Flood zones come from the Flood Map for Planning in England, and from Natural Resources Wales’ own planning map in Wales. Councils use them to decide where new building should go. Zone 1 has the lowest chance of flooding from rivers or the sea and Zone 3 the highest. The zones leave out flood defences, so a home in Zone 3 can still sit in a low band if it is well defended.
Flood warning and alert areas are places where the Environment Agency or Natural Resources Wales can send warnings when flooding is expected. Being in one tells you flooding is possible there, and you can sign up for warnings once you move.

Questions to ask before you commit

Ask the seller whether the home, garden or garage has ever flooded and whether they have made a flood insurance claim. The property information form the seller completes asks about past flooding.
Ask your conveyancer to go through the environmental and drainage searches. The drainage and water search can show whether the water company records a risk of sewer flooding at the property.
Get a buildings insurance quote for the exact address before you exchange contracts. Your lender will want the home insured, so you need to know the cost and the flood excess early.
Ask your surveyor to look for signs of past water damage and to comment on floor levels, drainage and any flood protection already fitted, such as flood doors or non-return valves on drains.
If the home is in a higher band, read the government’s advice on how to prepare for flooding.

Insurance, Flood Re and the longer term

Insurers price flood cover using their own data as well as the official maps, so quotes for neighbouring homes can differ. In higher-risk places, cover can cost more or come with a larger excess for flood claims.

Flood Re is a scheme run jointly by the government and insurers that helps many homes at high flood risk get affordable cover through ordinary insurers. Not every property qualifies: homes built from 2009 onwards are excluded, so it does not help new-build homes in flood-prone places. Ask an insurer or broker whether it applies to the home you are buying.

Climate projections point to wetter winters and more intense downpours, which raises the chance of flooding in many places, especially from surface water. If you expect to own the home for decades, look at the climate change view in the long term flood risk service as well as today’s band. While you are checking the surroundings, see how to check noise and air quality too.

Check it for a specific home

The Flood risk section of a HouseReport report gives the risk from rivers and the sea, surface water and groundwater for the home itself where the data allows, or for its postcode, and the Planning, heritage and land checklist includes flood risk at the home. Look up any address to see in the free preview which sections it has, then take the questions above to the seller, your conveyancer and an insurer.

Look up any address

The free preview shows which of these checks the report answers for that home.