If you have searched a property for flood risk recently and got a different answer depending on which tool you used, you are not imagining it. There are now two official Environment Agency flood datasets in circulation, they use different language, different risk bands and different methodologies — and most property professionals do not know which one they are looking at.
This post explains the difference, shows you where it matters in practice, and tells you what to check before your next site assessment or valuation.
The Short Version
The Flood Map for Planning is the older dataset. It uses Flood Zones 1, 2 and 3. It is the dataset used in the planning system and it is what most platforms — including LandLens — display by default because it is the legally relevant dataset for planning applications.
NaFRA2 (National Flood Risk Assessment 2) is the newer dataset. It was launched by the Environment Agency in December 2024. It uses Low, Medium and High risk bands. It includes surface water flooding as well as river and sea flooding. It is a more sophisticated risk picture but it does not replace the Flood Map for Planning in the planning system — yet.
The problem is that these two datasets do not always agree. A postcode that shows as Flood Zone 1 (lowest risk) on the planning map can show as Medium or even High risk on NaFRA2. For a surveyor, a developer or a lender, that difference matters enormously.
What the Flood Map for Planning Actually Shows
The Flood Map for Planning has been the standard reference for development control decisions in England for over two decades. It divides land into three zones:
- Flood Zone 1 — Low probability. Less than 1 in 1,000 annual probability of flooding from rivers or the sea. The majority of England falls here. Most development is acceptable without a flood risk assessment.
- Flood Zone 2 — Medium probability. Between 1 in 100 and 1 in 1,000 annual probability. A flood risk assessment is required for most development types. Sequential and Exception Tests may apply.
- Flood Zone 3 — High probability. Greater than 1 in 100 annual probability from rivers, or greater than 1 in 200 from the sea. The most restrictive zone. Certain development types are not permitted at all. Flood resilience measures are mandatory for those that are.
This dataset is what planning officers use when assessing applications. It is what the NPPF references. It is the dataset that determines whether your Sequential Test is required and whether your development is appropriate in principle.
What NaFRA2 Shows — and Why It Is Different
NaFRA2 was developed to give a more complete picture of flood risk across England. It was published in December 2024 and represents a significant methodological step forward from its predecessor NaFRA1.
Key differences from the Flood Map for Planning:
It includes surface water flooding
The Flood Map for Planning only covers river and coastal flooding. NaFRA2 adds surface water risk — the kind of flooding caused by heavy rainfall overwhelming drainage systems. This is increasingly significant given changing weather patterns, and it is the type of flooding most likely to affect urban properties that sit nowhere near a river.
It uses probability bands rather than zones
Instead of Zone 1/2/3, NaFRA2 expresses risk as High (greater than 1 in 30 annual probability), Medium (1 in 30 to 1 in 100), Low (1 in 100 to 1 in 1,000) and Very Low (less than 1 in 1,000). These bands do not map directly onto the Zone 1/2/3 framework.
It models future climate scenarios
NaFRA2 includes projections for how flood risk is expected to change under different climate scenarios. This is particularly relevant for mortgage lenders assessing long-term asset risk and for developers planning schemes with 20 to 30 year horizons.
It is not yet used in the planning system
This is the critical point. Despite being more sophisticated, NaFRA2 does not replace the Flood Map for Planning for development control purposes. Planning officers are still required to use Flood Zone classifications when determining applications. NaFRA2 is currently used for strategic flood risk assessment and emergency planning, not for individual planning decisions.
Where the Two Datasets Disagree — and Why It Matters
The most important thing to understand is that a property can look very different depending on which dataset you consult.
Scenario 1: Zone 1 but High NaFRA2 surface water risk
A property sits in Flood Zone 1 — so from a planning perspective it has the lowest flood risk classification and development is generally acceptable. But NaFRA2 shows it has High surface water risk because it sits at the bottom of a hill in a drainage catchment area. The planning system says it is fine. A mortgage lender using NaFRA2 data may flag it as a risk.
This scenario is common in older urban areas with Victorian drainage systems that are increasingly unable to handle peak rainfall events.
Scenario 2: Zone 3 but Low NaFRA2 overall risk
A property sits on the edge of a floodplain and is technically in Flood Zone 3 — triggering all the planning restrictions that come with it. But the property is protected by a flood defence scheme, and NaFRA2 — which accounts for current defences — shows residual risk as Low. The planning system still requires a Sequential Test. But the actual probability of the property flooding is lower than the Zone classification implies.
Scenario 3: Different answers for adjacent properties
Because the two datasets use different spatial resolution and different methodologies, two properties on the same street can receive genuinely different risk classifications on NaFRA2 even if they share the same Flood Zone on the planning map.
For valuers and surveyors, this is the scenario that creates the most difficulty. When two comparable properties in the same street have different NaFRA2 risk profiles, it raises questions about whether flood risk should be reflected in the valuation — and if so, by how much.
What This Means for Different Professionals
Planning consultants
For planning applications, always use the Flood Map for Planning as your primary reference. That is what the planning officer will use. NaFRA2 is not currently material to planning decisions in England. However, if you are advising on a strategic site or a long-term masterplan, NaFRA2 climate projections are worth understanding because they may inform future policy changes.
Property developers
The Flood Zone classification determines whether you need a Sequential Test and a Flood Risk Assessment — and those documents cost time and money. Check the Flood Zone early, before you commit to a site. If you are in Zone 2 or 3, budget for the assessment and build in time for the Exception Test if needed. Do not rely on NaFRA2 to override a Zone 3 classification — it will not help you with the planning officer.
Surveyors and valuers
You need to be aware of both. Flood Zone classification is relevant to planning consent risk and any future development potential of the property. NaFRA2 surface water risk is increasingly relevant to mortgage lenders who are updating their risk models. If you are valuing a property for a lender, understand which dataset their risk model references. Some lenders have already moved to NaFRA2 for portfolio risk assessment even though the planning system has not.
Mortgage lenders and investment funds
NaFRA2 is where your industry is heading. The inclusion of surface water risk and climate projections makes it a more complete basis for long-term asset risk assessment than the Flood Map for Planning. If your current risk models still reference Zone classifications only, NaFRA2 represents a material gap in your flood risk picture — particularly for urban portfolios.
The Practical Checklist
Before your next site assessment or valuation, run through these five checks:
- What Flood Zone is the property in? Zone 1, 2 or 3 from the Flood Map for Planning. This determines planning requirements.
- Is there a flood defence in place? Zone 3 properties protected by a formal defence scheme may have a lower residual risk than the zone implies. Check the EA’s flood defence data.
- What is the NaFRA2 surface water risk? Even Zone 1 properties can have significant surface water risk. This is increasingly relevant to lenders.
- Has the property flooded before? Historical flood events are recorded separately from zone classifications. Check the EA’s recorded flood outlines.
- Are there any planning constraints that compound the flood risk? A property in Zone 2 that is also in a conservation area or contains a listed building faces a more complex planning position. Flood resilience measures may conflict with heritage requirements.
How LandLens Handles This
LandLens displays Flood Map for Planning data — Zone 1, 2 and 3 — as part of the constraint map for any UK postcode. This is the legally relevant dataset for planning decisions and is what we prioritise because it is what planning officers, consultants and developers need to make site assessments.
We are actively evaluating the addition of NaFRA2 surface water risk as a separate layer, which would allow you to see both datasets side by side for any postcode in a single search. We will publish an update when that is live.
In the meantime, for any UK postcode you can check flood zone classification alongside conservation areas, listed buildings, green belt, Article 4 directions, brownfield register, ancient woodland, AONBs, national parks, SSSIs, planning applications and INSPIRE parcel boundaries — all in under 10 seconds.
Summary
The Flood Map for Planning and NaFRA2 are two different tools built for two different purposes. The planning system uses Flood Zones. Lenders and strategic risk assessment are increasingly using NaFRA2. Both matter depending on what you are trying to answer.
The confusion between them is causing real problems — sites being misjudged, valuations being challenged, and professionals giving conflicting advice to clients because they are referencing different datasets without realising it.
Know which dataset you are looking at. Know what question it answers. And check both before you advise a client on a property near water.