EA Flood Map for Planning: May 2026 Update — Surface Water Climate Change Data

On 28th May 2026 the Environment Agency added surface water climate change extents and banded depth layers to the Flood Map for Planning. The Check Your Long Term Flood Risk (CYLTFR) surface water data should no longer be used for development planning. Some sites now sit inside a mapped surface water risk area for the first time, which can trigger a new or updated flood risk assessment for planning, a Sequential Test, or a revised drainage strategy. Flood Zones are unchanged. And since the EA made these changes, the published August 2026 NPPF has put them on a statutory policy footing. Here is what the May 2026 update to the EA Flood Map for Planning means for your site, and what to do next.

Two changes now reinforce each other. Since 28th May 2026 the Flood Map for Planning carries surface water climate change extents and banded depth. Since 17th August 2026 the new NPPF names that map as the evidence base for when an FRA and the Sequential Test are required.

Key takeaways

• What was added: surface water climate change extents and banded depth layers, live on the Flood Map for Planning (FMfP) since 28th May 2026.
• Climate change basis: the extents use the upper-end (95th percentile) allowance for the 2070s epoch, replacing CYLTFR's central (50th percentile) 2050s assumption.
• Banded depth: seven depth bands for the 3.3%, 1% and 0.1% AEP events, present day and with climate change.
• Stop using CYLTFR: from 28th May 2026 the Check Your Long Term Flood Risk surface water layers are out for development planning.
• Flood Zones unchanged: the river and sea Flood Zones, and the present-day surface water extents already on FMfP, are the same.
• New policy weight: the August 2026 NPPF (Policy F4) can require an FRA on any site the maps show at risk from surface water, and Policy F5 lets a well-evidenced FRA lift the Sequential Test for surface-water-only sites.
• Practical point: pull the new layers into your GIS through live data feeds, not static downloads, so your tools always show the current version.

The Environment Agency added the surface water climate change extents and banded depth layers to the Flood Map for Planning on 28th May 2026. It is the third major refresh in just over a year, after the March 2025 NaFRA2 launch and the August 2025 Flood Zones plus climate change layer. The CYLTFR surface water datasets stopped being used in development planning on the same day. For the wider planning picture, from how surface water feeds the Sequential Test to climate change allowances and SuDS design, see our complete guide to surface water flooding and planning.

What changed on 28th May 2026

The May 2026 Flood Map for Planning update added two datasets. First, surface water flood risk extents with climate change, modelled against the upper-end (95th percentile) climate change allowance for the 2070s epoch (2061 to 2125). Second, banded depth information for surface water, for both present day and with climate change.

Depths come in seven bands (<150 mm, 150 to 300 mm, 300 to 600 mm, 600 to 900 mm, 900 to 1,200 mm, 1,200 to 2,300 mm and >2,300 mm) for the 3.3%, 1% and 0.1% annual exceedance probability (AEP) events. The same layers sit on the Defra Data Services Platform (DSP) for download into GIS. The Flood Zones and the present-day surface water extents already on FMfP are unchanged.

Why this matters for FRAs, SuDS and SFRAs

The new layers do two specific things for the planning case. The climate change scenario has moved from CYLTFR's central (50th percentile) 2050s allowance to the upper-end (95th percentile) 2070s allowance. That puts surface water on the same time horizon as the EA's flood risk assessment climate change allowances and the climate change layers already running for rivers and sea. Some sites that previously screened out of surface water risk now fall within a mapped risk area. Others pick up more detail on their flow paths. If you need the percentiles and epochs unpicked, our 2026 guide to climate change allowances sets out which figure applies where.

CYLTFR told you the chance of flooding to a given depth. The new bands give the depth expected in a given scenario, which is the number a planning-grade assessment actually needs to set finished floor levels and size a drainage design.

That second change is the more useful one. The banded depth data finally provides a design flood depth. The new bands match the AEP events planning policy already references, so on routine sites they can cut bespoke modelling, and they give LLFAs a consistent depth dataset to assess submissions against. It feeds straight into a surface water drainage strategy: attenuation volumes, exceedance routing and finished floor levels can now be read off a national dataset rather than argued from probability. Strategic Flood Risk Assessments (SFRAs) benefit from the same change. LPAs whose SFRAs lean on CYLTFR for surface water climate change information will need to refresh those passages, and sites allocated on the back of the old mapping may need a fresh look.

What the update means for developers and planners

For many sites, nothing changes. The present-day picture is the same and the site stays clear of mapped surface water risk. But on sites near existing flow paths or low spots, the new climate change extents can pull land into a mapped surface water (pluvial) flood risk area that was previously clear. Surface water now dominates urban flood risk in England, and rising rainfall intensity is pushing more sites over the threshold. In practice the new layers can mean one or more of the following.

• A surface water FRA, or a surface water section added to an existing FRA. If you are unsure what that involves, see our guide on how to do a flood risk assessment.
• A Sequential Test, unless a site-specific FRA shows occupiers stay safe for the lifetime of the development, the surface-water-only route now written into Policy F5.
• A revised drainage strategy informed by banded depth rather than probability-of-depth. Our note on what drainage information is needed for planning covers what a validating authority expects.
• Higher finished floor levels or a revised layout where the banded depths are significant, which interacts with the flood risk vulnerability classification of the proposed use.

The earlier you check a site against the new layers, the cheaper any redesign is. It is far better to find this at feasibility than at the consultation stage.

A worked example

Take a small residential scheme on the edge of an existing built-up area. Under the old CYLTFR surface water mapping, central (50th percentile) allowance on a 2050s horizon, the site screened out: no mapped surface water risk, no surface water section needed in the FRA. Under the new 28th May layers, modelled at the upper-end (95th percentile) allowance for the 2070s, a shallow flow path along the site's northern boundary now appears, carrying a 300 to 600 mm banded depth in the 1% AEP event with climate change.

That single change cascades. The site now needs a surface water assessment within the FRA. Finished floor levels along the affected frontage have to sit above the modelled depth plus freeboard. The SuDS layout has to keep that flow path clear and convey it safely. And because the site has moved into a mapped risk area, the LPA may ask for a Sequential Test unless the FRA demonstrates occupiers stay safe for the development's lifetime. None of this is fatal to the scheme. Found late, it is expensive. Found at feasibility, it is a layout tweak.

The May 2026 update and the August 2026 NPPF

The map change did not happen in a policy vacuum. Two moves had already raised the bar on surface water before the data landed, and a third has since hard-wired it. The September 2025 PPG update confirmed that the Sequential Test must consider all flood sources, including surface water with climate change. The December 2025 draft NPPF then treated flood risk as a primary spatial constraint rather than a sub-heading of climate change.

On 17th August 2026 the Government published the new National Planning Policy Framework, and it applies to every decision made from that date, including applications already submitted under the December 2024 version. Flood risk now sits in a dedicated Chapter 18 with nine coded policies, F1 to F9, and the flood zone definitions and vulnerability classification move into the Framework itself as a new Annex F. Our analysis of the August 2026 NPPF changes walks through all nine policies; three of them bear directly on this map update.

• Policy F4 drops the old "more vulnerable use" qualifier, so any site the SFRA or the Flood Map for Planning shows at risk from any source, surface water included, can now need an FRA. The May 2026 layers are what put more Flood Zone 1 sites into that net.
• Policy F5 names the FMfP and SFRA as the Sequential Test evidence base, caps the area of search at the development's likely catchment, and adds a surface-water-only exemption where a site-specific FRA proves lifetime safety. Seventeen insurance and flood bodies, including the ABI, Aviva and Flood Re, opposed that exemption in consultation and it survived unchanged.
• Policy F8 makes design to the 2025 National Standards for Sustainable Drainage Systems mandatory for all development, major or minor, so the banded depth you read off the new map has to carry through into a compliant SuDS scheme.

Two knock-on points are worth flagging. The vulnerability classification that decides what can go where, once at Annex 3, is now Annex F, Table 2, and the compatibility table now carries explicit "should be refused" outcomes. And the tests themselves, renumbered into Policies F5 and F6, are set out in our guide to the Sequential and Exception Tests. If you would rather hand the policy read-across to someone else, our NPPF flood risk guidance service does exactly that.

How to read the new banded depth data

The seven depth bands are the most practically useful part of this release, but only if they are read correctly. Each band gives the modelled depth of water in a given scenario, not the probability of reaching a depth, which is the change from CYLTFR. Read alongside the relevant AEP event (3.3%, 1% or 0.1%), the bands map onto real design decisions.

Because the bands now match the AEP events planning policy already references, they can usually be used directly to set finished floor levels and to size SuDS, rather than commissioning bespoke modelling on routine sites. Where depths or flow paths are complex, or where you need to demonstrate level-for-level compensatory storage, site-specific modelling is still the right route. For larger or more sensitive schemes, EA Product 4 flood risk data requested through the FMfP service remains the better source where a suitable local model exists.

How to access the new layers in your GIS

The single most important practical point is to connect to the data as a live feed rather than downloading a static copy. The surface water climate change extents and banded depth layers are on the Flood Map for Planning and are also published on the Defra Data Services Platform for download into GIS. Pulling them through the published web feeds means your QGIS or ArcGIS project always reflects the current version, which matters on a dataset the EA will keep refining.

If you maintain your own flood-data layers, retire the CYLTFR surface water layers, present-day and climate change, extents and depths, at the same time, so old and new data cannot be confused. It is also worth understanding how this dataset sits alongside the wider Environment Agency flood data products and the national picture in NaFRA2, so the right source is used for the right question.

What planners, developers and LPAs need to do

The EA did not release the new datasets to LPAs or LLFAs ahead of publication, so 28th May was a single switch day for the whole sector. Now the layers are live, the practical steps are straightforward.

1. Add the new layers via data feeds, not static downloads, so your GIS always shows the latest version.
2. Remove the CYLTFR surface water layers, present-day and climate change, extents and depths, from your development planning tools.
3. Agree transitional arrangements with the LLFA. Sites that have moved into a mapped risk area may trigger a new FRA, a Sequential Test (subject to exemptions), or an update to an existing FRA, Sequential Test or surface water drainage strategy.
4. Where the LLFA has already advised on a live application, agree with the LPA whether re-consultation is needed. There is no need to re-consult the Environment Agency, which is not a statutory consultee on surface water flood risk.

If you have a live application caught by the switch, the most common pressure points are an LLFA objection on drainage or an EA flood-risk objection arriving after the data changed. With the April 2026 planning appeal rules raising the bar on getting flood risk and drainage right first time, it is worth a quick review of any in-flight scheme now rather than at decision. And if you believe a site has been mapped into surface water risk incorrectly, there is a defined route to challenge the EA flood map.

What you should stop using

From 28th May 2026, stop using the Check Your Long Term Flood Risk (CYLTFR) surface water layers for development planning. Remove both the present-day and the climate change surface water layers, extents and depths, from your GIS tools, and use the surface water layers on the Flood Map for Planning instead, pulled via live data feeds. Version 4.0 of the EA's Product Suitability for Planning Diagram (May 2026) classifies every CYLTFR surface water layer as unsuitable for development planning, and marks the new banded depth layers as suitable. If a site reads Flood Zone 3 on the FMfP but "Low" on the public long-term map, our explainer on why you cannot use the long term flood risk map for planning sets out which map governs and why.

Supporting resources

The Town and Country Planning Association hosts version 4.0 of the EA's Product Suitability for Planning Diagram, which applies from 28th May. Every CYLTFR surface water layer is classified as unsuitable for development planning, and the new surface water banded depth layers are marked as suitable. The diagram, the EA's briefing note and the supporting e-learning sit together on the TCPA's resources page. The EA refreshed several supporting documents on the same day. They include how-to guidance on using FMfP data, the National Flood Risk Standing Advice for LPAs, the guidance on preparing an SFRA, and the developer and consultant guidance "Flood risk assessments: applying for planning permission".

Looking beyond 28th May

Two FMfP updates landed in May: the 20th May routine refresh of the Flood Zones and Flood Zones plus climate change layers, and the 28th May surface water release. Anyone using FMfP through GIS should pull updates via data feeds. Rivers and sea banded depth information is due later in 2026, on the Defra Data Services Platform first and only in locations covered by the national model. Where a suitable local model already exists, Product 4 flood risk assessment data requested through the FMfP service is still the better source for site-specific depth, and any new modelling should meet the EA's 2026 river modelling technical standards.

How Unda can help

We are seeing a steady stream of sites that need a fresh look against the new FMfP layers, FRAs that reference CYLTFR and need updating, and live applications that straddled the 28th May switch. If any of that sounds familiar, get in touch. We can take a look and talk through what the new data and the August 2026 NPPF mean for your flood risk assessment and your surface water drainage strategy.

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