NPPF Flood Risk Assessment Guidance and Advice

NPPF flood risk assessment guidance starts with one document: the National Planning Policy Framework, the Government's statement of national planning policy for England. On 17 August 2026 a new version came into force, replacing the December 2024 Framework in full and applying to every planning decision taken from that date. If your development touches flood risk in any form, this is the policy that decides which reports you must submit — a flood risk assessment, a sequential test, sometimes an exception test, and increasingly a drainage strategy. This page explains what the current Framework requires and points you to the right report for your site. We have completed more than 5,000 flood risk assessments since 2014.

The NPPF is planning policy, not a report you can buy, but it sets the evidence every flood-affected application has to carry, and getting that evidence right is usually what decides the application.

What is the National Planning Policy Framework?

The National Planning Policy Framework (NPPF) is the Government's national planning policy for England. It sets out how councils should plan for new development and how they should decide individual planning applications. Flood risk runs right through it: the Framework steers development away from the places most likely to flood, and where building in a flood-risk area is unavoidable, it sets the tests a scheme has to pass to be allowed.

The Framework was first published in 2012, replacing the old Planning Policy Statement 25 that introduced the sequential and exception tests. It was revised in December 2024, then rewritten and republished in August 2026. That August 2026 version is the one in force today. It does not apply in Wales, where development on flood-risk land is governed by TAN15 and Planning Policy Wales and the report you need is a flood consequence assessment rather than an FRA.

What changed when the August 2026 NPPF came into force?

The August 2026 NPPF is a full rewrite rather than a set of amendments. The old flood paragraphs 170 to 185 have gone; flood risk and coastal change now sit in a dedicated chapter of nine coded policies, F1 to F9, backed by a new Annex F that brings the flood zone definitions, the vulnerability classification and the zone compatibility table inside the Framework for the first time. Climate change policy moved to Chapter 5 and water and drainage infrastructure to Chapter 10. Our full guide to the August 2026 NPPF changes works through each policy in turn.

Six changes matter most for day-to-day flood risk and drainage work, and the map below shows where the old rules landed.

The changes are more than tidying. The permissive wording of the old flood paragraphs has become refusal-worded policy, and Annex A gives local plan policies that conflict with the new Framework very limited weight. That combination raises the value of getting the flood evidence right the first time.

How does the NPPF manage flood risk?

The Framework takes a sequential, risk-based approach, supported by the Government's Planning Practice Guidance on flood risk and coastal change: keep development out of the highest-risk areas where you can, and where you cannot, make it safe for its lifetime without pushing flood risk onto anyone else. Two separate classifications drive this, and it helps to keep them apart.

• Flood zones describe how likely a piece of land is to flood from rivers or the sea, from Zone 1 (low probability) up to Zone 3b, the functional floodplain that has to store or convey flood water. Annex F Table 1 now defines them, including the Zone 3a and 3b split that the Flood Map for Planning does not show.
• The vulnerability classification describes how sensitive a proposed use is to flooding, from water-compatible uses up to highly vulnerable ones such as basement dwellings. Annex F Table 2 sets it out, and Table 3 shows which combinations of zone and use are appropriate, which need the exception test, and which should be refused outright.

Reading those two tables together is how you find out whether a scheme is acceptable in principle, whether it needs the exception test, or whether it faces a refusal instruction before design even begins. Our guide to the flood risk vulnerability classification and our explainer on flood zones 1, 2 and 3 go through both in plain terms.

When is a flood risk assessment required under the NPPF?

Under policy F4, a site-specific flood risk assessment must accompany all development in Flood Zones 2, 3a and 3b. In Flood Zone 1, the low-probability zone, an FRA is now needed in a wider set of cases than before, because the old qualifier that development had to introduce a more vulnerable use has been dropped. You need an FRA on a Zone 1 site if any of the following apply.

• The site is one hectare or more. Size alone brings a Zone 1 site into scope.
• The land is shown at risk from any source. If a strategic flood risk assessment or the Flood Map for Planning shows the land at risk from any source now or in the future, an FRA is required — and since the May 2026 map update added surface water climate change layers, that now catches many sites the old maps left clear.
• The Environment Agency has flagged critical drainage problems on the land.
• A change of use raises the vulnerability classification of the site, for example a more sensitive residential use replacing a commercial one.

Because the Flood Map for Planning now displays surface water risk, more Flood Zone 1 sites formally need an FRA than under the December 2024 Framework. If you are not sure whether your site is caught, our guide on when you need a flood risk assessment sets out the triggers, and you can screen the location yourself on our free flood risk map postcode checker.

Which flood risk report does your planning application need?

This page explains the policy; it is not itself the report you submit. Once you know what your site needs, these are the services that produce each piece of evidence. If you have landed here but your situation is more specific, use the list below to reach the right page.

• A planning application in England. You need a flood risk assessment for planning, the core site-specific report submitted with the application.
• A site in Flood Zone 2 or 3, or flagged for surface water. You are likely to need sequential and exception test reports alongside the FRA.
• A council asking how surface water will be managed. You need a surface water drainage strategy, or one of our wider drainage strategies.
• A development in Wales. The NPPF does not apply; you need a flood consequence assessment under TAN15.
• A BREEAM assessment. You need a flood risk assessment for BREEAM, scoped for the Pol 03 credit.
• Buying a home flagged for flood risk. You need an independent flood risk survey for property purchase, not a planning FRA.
• An insurer questioning your risk. You need a flood risk assessment for insurance.
• A basement, or chalk or gravel ground. You may need a groundwater flood risk assessment.
• A site where the national maps do not fit. You may need flood modelling to quantify levels and extents.

If none of those is quite right, speak to our consultants and we will point you to the correct evidence for your site.

The sequential and exception tests under the NPPF

The sequential test, now policy F5, is the Framework's central mechanism for steering development to lower-risk land. Its aim has not changed: where the test applies, a proposal should not go on flood-risk land if there are reasonably available sites, suitable for the development, in an area at lower risk. Two changes in the August 2026 version matter for how the test runs.

• The area of search is capped. It should not be greater than the development's anticipated catchment in terms of its likely occupiers or users — a firmer limit than the old proportionality wording, and useful when a council presses for a borough-wide search on a local scheme.
• Surface-water-only sites can be exempt. Where a site is at risk of surface water flooding alone, the sequential test is not required if the FRA demonstrates clearly that layout, design and mitigation will keep people safe for the development's lifetime without increasing flood risk elsewhere. This shifts the weight onto the surface water chapter of the FRA, which now has to prove the case the test used to.

The exception test, now policy F6, applies only to river and sea flooding in Flood Zones 2, 3a and 3b, and it now has three limbs rather than two: wider sustainability benefits, lifetime safety, and no increase in flood risk elsewhere with a reduction where possible. When a use is incompatible with its flood zone under the Annex F table, the policy says the application should be refused. Recent case law, including Mead and the Yatton judgment, still governs how a failed test is weighed, but the refusal-worded policy changes the ground it is argued on. Our sequential and exception test reports build the evidence for both, and our review of the September 2025 PPG update covers the guidance behind them.

Drainage, SuDS and the NPPF

Drainage is where the August 2026 Framework changed most. Policy F8 makes design in accordance with the 2025 National Standards for Sustainable Drainage Systems a national policy requirement, and it applies to all development, not just major schemes. Only the requirement to take Lead Local Flood Authority advice is still confined to major development. In practice this means the national standards, the discharge hierarchy and lifetime maintenance now bear on small schemes as well as large ones, and a SuDS statement showing how those standards have been met is a national information requirement for any application that could affect drainage.

Policy F8 also breaks new ground on watercourses: no new culverting without compelling reasons, and existing culverts should be removed and channels renaturalised where that can be done without increasing flood risk or causing other harm. On constrained urban sites with a culverted watercourse crossing them, that is now a layout consideration from day one. Our guides to the 2025 National Standards for SuDS, the SuDS discharge hierarchy and the four pillars of SuDS unpack what the standards ask for, and our surface water drainage strategy service produces the statement councils now expect.

What an NPPF-compliant flood risk assessment must show

Whatever the site, an FRA prepared to the current Framework has to do more than repeat the published maps. Policy F4 ties the assessment to the sequential and exception tests, and policy F7 sets the safety tests it has to answer. A compliant report demonstrates the following.

• Every flood source assessed. Rivers and the sea, surface water, groundwater, sewers and artificial sources, and the effect of climate change on each.
• The flood data appraised, not just quoted. Since April 2025 an FRA has to judge whether the datasets it relies on are suitable for the site, and note their provenance and limitations.
• Current climate change allowances applied over the development's lifetime, taken as at least 100 years for housing, using the Environment Agency's published climate change allowances. Our guide to how the allowances are chosen explains them in plain terms.
• Finished floor levels set to Ordnance Datum with resistance and resilience measures where they are needed.
• Safe access and escape demonstrated for the people who will use the development, including visitors.
• No flood risk displaced elsewhere, shown for the site and its surroundings.

A report that is thin on any of these is the one most likely to draw a further-information request, an objection, or a refusal. Our guides on how a flood risk assessment is done and whether you need an FRA and a drainage strategy show what a strong submission looks like.

Flood zones and the vulnerability classification

Annex F now carries the definitions the Framework used to leave to guidance. The table below sets out the flood zones by annual probability of river or sea flooding. Zone 3b, the functional floodplain, is identified in strategic flood risk assessments in agreement with the Environment Agency and is not separately shown on the Flood Map for Planning.

Two catches trip up otherwise sound schemes. A basement is a highly vulnerable use, which can pull a proposal out of Zone 3a even where the rest of the building would be acceptable; and a mixed-use scheme is generally assessed at the highest vulnerability present unless it can be considered in its separate parts. The August 2026 classification also moved data centres, electric vehicle charging, hydrogen production and heat networks into essential infrastructure, which changes how those uses are treated on flood-risk land.

Coastal change under the NPPF

If your site is on or near the coast, an estuary or a tidal river, policies F3 and F9 apply as well. The August 2026 Framework strengthened them: Shoreline Management Plans and the National Coastal Erosion Risk Map are named in policy for the first time, and F9 now reaches beyond designated Coastal Change Management Areas to any land likely to face erosion or tidal inundation over the next century. New residential development in such areas is treated as inappropriate unless the F9 tests are met. Our explainer on Shoreline Management Plans covers how those plans are read.

Who enforces NPPF flood risk policy?

Policy is only as strong as the people applying it, and on a flood-affected application that is usually a small group of consultees.

• The local planning authority decides the application and weighs the flood evidence against the Framework and its local plan.
• The Environment Agency is the statutory consultee on river and sea flood risk, generally where a site is in Flood Zone 2 or 3 or within 20 metres of a main river, and publishes its own flood risk assessment standing advice. Our guide to planning appeals in 2026 explains why an unresolved objection is now so hard to recover from.
• The Lead Local Flood Authority advises on surface water drainage for major development, and can now object by citing a named national standard rather than a local preference. Our guide on resolving an LLFA objection covers the common failures.
• The strategic flood risk assessment is the council's own evidence base, and policy F5 makes it and the Flood Map for Planning the joint basis for the sequential test.

What the August 2026 NPPF means for your application

The new policies are material to every application decided from 17 August 2026, including those submitted under the December 2024 Framework, so any live application on flood-affected land is worth re-checking against F4 to F9 and Annex C. Some proposals gain: a surface water site may lose its sequential test, and an allocated site may escape re-running the exception test. Others are exposed, such as a Zone 1 site that now needs an FRA it did not have, or a drainage strategy with no national-standards statement.

Two timing points are worth holding in mind. A drainage statement and the FRA are increasingly validation-stage documents rather than things to be conditioned later, so the technical work moves earlier in the programme. And with the appeals regime restricting new evidence from April 2026, and most decisions moving to officers from the end of October 2026, a weak first submission is harder to rescue than it used to be. Our note on why flood-risk schemes are approved or refused sets out what that means in practice.

How Unda helps you comply with NPPF flood risk policy

We are a specialist flood risk and drainage consultancy, and flood policy is the core of what we do. Our experienced consultants are Chartered members of CIWEM, and every report is signed off by a senior consultant before it goes to a council. Because we track policy as it moves, through the September 2025 PPG update, the December 2025 draft and now the August 2026 Framework, the evidence we produce is written to the rules in force, not the ones that have just been replaced.

• One joined-up evidence package. The FRA, the sequential and exception tests, the drainage strategy and any modelling are prepared together, so the documents agree with each other rather than contradict.
• Deep local knowledge. Published flood risk guides for more than 230 towns, cities and counties, the major rivers, and individual local planning authorities.
• Free tools to screen a site. A flood risk map postcode checker, a live river levels map and a full suite of drainage calculators, plus a 444-term flood risk and drainage glossary.
• A quote within the hour. Tell us about the site and we return a fixed, tailored quote within 60 minutes on a working day.

Frequently asked questions

To talk through what the current NPPF requires for your development, speak to our experienced consultants on +44 (0) 1293 214444 or email enquiries@unda.co.uk. We will tell you which reports your site needs and return a fixed, tailored quote within the hour.