Quick answer
To check flood risk before buying a house in England, enter the postcode on GOV.UK's Check your long term flood risk service.1 It rates the area's risk from rivers and the sea, surface water and reservoirs as high (more than a 3.3% chance a year), medium (1–3.3%), low (0.1–1%) or very low (under 0.1%).2 Then ask the seller whether the home has flooded, and get an insurance quote before you exchange.
Key takeaways
- Free check: GOV.UK's long-term flood risk service, by postcode.1
- It covers rivers and the sea, surface water and reservoirs. Groundwater is not modelled.2
- High risk means more than a 3.3% chance of flooding each year; very low means under 0.1%.2
- Risk is for the area around the address, not the building itself.2
- Flood Re helps insure homes built before 1 January 2009; newer homes are not eligible.5
Flood risk is one of the few problems you can check in five minutes, for free, before you spend anything on a survey. The Environment Agency's data was rebuilt in 2025 from a new national assessment, so a check done on an old listing may be out of date.3
This guide covers England. In Wales, check Natural Resources Wales' flood maps instead; in Scotland, SEPA's.
How do you check a house's flood risk for free?
Go to Check your long term flood risk on GOV.UK1 and enter the postcode, then choose the address area on the map. The service gives a separate rating for each source of flooding and shows the area at risk on a map, so you can see whether the house sits at the edge of a risk area or in the middle of it.
Look at both the river and sea risk and the surface water risk. Surface water flooding, from heavy rain that drains cannot cope with, affects many homes nowhere near a river.
What do high, medium, low and very low mean?
A 1% yearly chance sounds small, but over a 25-year mortgage it is about a 22% chance of at least one flood. A 3.3% yearly chance is more likely than not over 25 years.
| Rating | Chance of flooding each year | Roughly |
|---|---|---|
| High | More than 3.3% | More than 1 in 30 |
| Medium | 1% to 3.3% | 1 in 100 to 1 in 30 |
| Low | 0.1% to 1% | 1 in 1,000 to 1 in 100 |
| Very low | Less than 0.1% | Less than 1 in 1,000 |
Source: GOV.UK flood risk data definitions. Ratings for rivers and the sea allow for flood defences.
What are flood zones, and do they matter to a buyer?
Flood zones come from the Flood Map for Planning, which councils use for planning decisions.4 Zone 1 has less than a 0.1% yearly chance of river or sea flooding; Zone 2 between 0.1% and 1% from rivers (0.5% from the sea); Zone 3 has 1% or more from rivers or 0.5% or more from the sea. The zones ignore flood defences, so they can look worse than the long-term risk rating.
They matter if you plan to extend or rebuild: building in Zones 2 and 3 usually needs a flood risk assessment. They were redrawn in March 2025, so check the current map rather than an old search.3
How do you check flood insurance before you buy?
Get a buildings insurance quote for the exact address before you exchange contracts. Your lender will require buildings cover from exchange, and an unaffordable quote is a reason to renegotiate or walk away while you still can.
Flood Re, the scheme that keeps flood cover affordable for high-risk homes, only covers homes built before 1 January 2009.5 A newer home in a flood risk area relies on the open market, which can mean a high premium or a large flood excess.
Checklist: questions to ask about flooding
Ask the seller, through the agent, before you offer:
| Question | Why it matters |
|---|---|
| Has the property ever flooded? When, and from what? | Past flooding is the best predictor of future flooding |
| Have you made a flood insurance claim? | Claims affect future premiums |
| Is the home insured through Flood Re? | Shows the insurer treats it as high risk |
| Are there flood defences or resistance measures (barriers, raised sockets)? | Can cut damage and sometimes premiums |
| Is there a flood excess on the current policy? | A high excess signals how insurers view it |
The seller answers these again in writing on the property information form your conveyancer receives.
After your offer is accepted, your conveyancer's environmental search covers flood risk for the exact address, and a surveyor will note signs of past water damage.
Use the calculator for this topic
Frequently asked questions
Is checking flood risk free?+
Yes. GOV.UK's Check your long term flood risk service is free and covers every address area in England.
Does the flood risk check cover groundwater?+
Not as a modelled risk. The service covers rivers and the sea, surface water and reservoirs, and only gives information about groundwater flood alerts.
Can I get a mortgage on a house at high flood risk?+
Often yes, but the lender will need buildings insurance in place from exchange. Get an insurance quote before you commit.
Is a new-build home covered by Flood Re?+
No. Flood Re only covers homes built before 1 January 2009.
Did the flood maps change recently?+
Yes. The Environment Agency published a new national flood risk assessment from December 2024, and flood zones were updated in March 2025.
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OfficialThe figures and rules on this page are drawn from the official UK government sources below. Rates are the confirmed 2026/27 amounts. Each link opens the relevant official page in a new tab.
- GOV.UK: Check your long term flood risk check-long-term-flood-risk.service.gov.uk Rivers and sea, surface water and reservoirs; high, medium, low and very low.
- GOV.UK: Flood risk data definitions check-long-term-flood-risk.service.gov.uk/risk-data High: over 3.3% a year; medium 1–3.3%; low 0.1–1%; very low under 0.1%. Groundwater is not modelled.
- GOV.UK: Updates to national flood and coastal erosion risk information www.gov.uk/guidance/updates-to-national-flood-and-coastal-erosion-risk-information New national assessment (NaFRA2) published from December 2024; flood zones updated March 2025.
- GOV.UK: Flood risk and coastal change (flood zones) www.gov.uk/guidance/flood-risk-and-coastal-change Flood Zones 1, 2, 3a and 3b defined by annual probability.
- Flood Re: eligibility www.floodre.co.uk/eligibility/ Homes built after 1 January 2009 are not eligible.
Verified against published UK government guidance. See also Methodology and Editorial standards.