The Environment Agency publishes two main ways of looking at flood risk in England, and they don’t always agree. A home can be in Flood Zone 3 but show ‘low’ risk from rivers and the sea on the long-term flood risk service – or sit in Zone 1 but be at ‘high’ risk of surface water flooding. Here’s why.
Flood zones: the planning map
The Flood Map for Planning divides land into Zones 1, 2 and 3. It’s built for one job: helping councils decide where new development should go. It deliberately:
- ignores flood defences, because defences can fail or be overtopped, and new homes will last longer than many defences are designed for;
- covers only rivers and the sea;
- uses fixed thresholds – Zone 3 is a 1% or greater yearly chance from rivers, or 0.5% or greater from the sea.
Long-term flood risk: the ‘what’s likely’ view
The long-term flood risk service is designed for homeowners. It takes defences into account where they exist, and gives a risk band for rivers and the sea, and separately for surface water:
- High – more than a 3.3% chance of flooding each year
- Medium – between 1% and 3.3%
- Low – between 0.1% and 1%
- Very low – less than 0.1%
It also shows reservoir flooding and says whether groundwater flooding is possible in the area.
Why they disagree
- Defences. A street behind a flood wall stays in Zone 3 on the planning map, but may be ‘low’ on the long-term service because the wall reduces the chance of water getting in.
- Surface water. A home on a hillside may be in Zone 1, far from any river, yet be at ‘high’ risk from surface water because rainwater runs off and collects there.
- Different thresholds. The bands and the zones use different cut-offs, so ‘Zone 3’ and ‘high’ don’t line up exactly.
Which one should you use?
Both. Use the flood zone if you’re thinking about planning permission, and because buyers, surveyors and some lenders will ask about it. Use the long-term risk bands to understand the day-to-day likelihood, including surface water. Insurers use neither directly – they have their own models – which is why a quote for the exact address is the final check.
If the two maps disagree, ask why. The answer is usually defences or surface water, and both are worth knowing about.
Last reviewed November 2026. This guide is general information about England, not legal, financial or insurance advice. Check the Environment Agency’s own services and speak to a professional before making decisions about a specific property.
