Flood Risk Tools • How-To Guide

The Flood Map for Planning, Explained

The Environment Agency's Flood Map for Planning is the map that decides whether your development needs an FRA. Here's how to read it — and what Flood Zones 1, 2 and 3 really mean.

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What the Flood Map for Planning is

The Flood Map for Planning is the Environment Agency's official map of flood risk from rivers and the sea, used specifically in the planning system. Unlike the long-term risk checker (which is an area indicator), this map assigns a flood zone to a location — and that flood zone is what determines the planning requirements, including whether you need a Flood Risk Assessment and a Sequential Test.

It's important to understand that the flood zones ignore the presence of flood defences — they show the risk as if no defences existed. That's why a site can be shown in Flood Zone 3 yet be well defended in practice; an FRA is what assesses the actual, defended, site-specific risk.

Open the Flood Map for Planning →

How to use it — step by step

Four quick steps to get what you need from the tool.

1. Search your site

Enter the postcode, or use the map to find and outline your site. You can draw the red-line boundary to get a report for the exact area.

2. Identify the flood zone

The map colours the land by flood zone. Zone 1 is low probability, Zone 2 medium, and Zone 3 high — with Zone 3b the functional floodplain where water flows or is stored in a flood.

3. Request the detailed information

For a planning application you can request the detailed flood risk information (historic mapping, modelled extents, defences) direct from the EA — the data an FRA is built on.

4. Work out what's required

Zone 1 sites over 1ha, and all Zone 2/3 sites, need an FRA. More vulnerable development in Zone 3a (and highly vulnerable in Zone 2) must also pass the Exception Test.

Flood zones and what they require

Zone 1 (low, under 0.1%/year) — FRA only if over 1ha or a major/at-risk site. Zone 2 (medium) — FRA required. Zone 3a (high) — FRA plus, for more vulnerable uses, the Sequential and Exception Test. Zone 3b (functional floodplain) — most development is not appropriate. If your site falls in Zone 2 or 3, send us the address and we'll quote a fixed-fee FRA and tell you exactly what's needed.

Related: Flood Zone 2 & 3 FRAs  •  Sequential & Exception Test  •  Check your long-term flood risk

Frequently Asked Questions

Does the Flood Map for Planning take flood defences into account?
No — the flood zones deliberately show the risk as if no defences existed, so a well-defended site can still sit in Flood Zone 3. A Flood Risk Assessment is what establishes the actual, defended, site-specific risk.
What is the difference between Flood Zone 3a and 3b?
Both are high probability. Zone 3a is land with a 1 in 100 or greater annual chance of river flooding (1 in 200 from the sea) where development can be acceptable with an FRA; Zone 3b is the functional floodplain, where water must flow or be stored in a flood and only water-compatible or essential infrastructure is normally allowed.
Can I get more detailed flood data than the map shows?
Yes. You can request the Environment Agency's detailed flood risk information (a Product 4) for a site, giving modelled flood levels, extents, historic flooding and defence details — the data a proper FRA is built on. We obtain and interpret this as part of every FRA.

Not sure what your result means?

Send us your postcode and we'll tell you, free, whether your site needs a Flood Risk Assessment.

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