Planning policy
National planning policy on flood risk and drainage is in the middle of a change. This page sets out what applies to your application today, what is proposed, and what it would mean in practice — so you can see which of the two your scheme is likely to be determined under.
Where this stands at the time of writing (September 2026). The NPPF of December 2024 is the operative version and is what your application is assessed against. A revised draft was published in December 2025 and remains a draft — it is not planning policy, and nothing on this page about it should be treated as a requirement yet. We review this page when the position changes.
What applies now: the December 2024 NPPF
Sustainable drainage is the default, not an option
Applications that could affect drainage should incorporate sustainable drainage systems to control flow rates and reduce runoff volumes, and development should include SuDS unless there is clear evidence that they would be inappropriate. The burden sits on demonstrating why not, rather than on justifying why.
That is a wider test than many people expect. It is not confined to major development — it attaches to applications that could affect drainage, which on a constrained site can include a good deal less than ten dwellings.
Three extra requirements on major development
Where the development is major, the drainage also has to:
- take account of advice from the lead local flood authority
- have appropriate proposed minimum operational standards
- have maintenance arrangements in place to ensure an acceptable standard of operation for the lifetime of the development
The third of those is the one most often left until last. A maintenance plan is part of the policy test, not an afterthought — which is why so many authorities condition it separately. See example drainage conditions.
A sequential, risk-based approach
Applications in areas at risk of flooding from any source are approached sequentially, steering development towards the lowest risk. Where development in a higher-risk area is necessary, it has to be made safe for its lifetime without increasing flood risk elsewhere.
“Any source” is doing real work in that sentence. Surface water, groundwater and sewer flooding count, not only rivers and sea — which is why a site in Flood Zone 1 can still need a flood risk assessment.
What the December 2025 draft proposes
Draft only. None of the following is policy at the time of writing.
Flood risk becomes its own chapter
Flood risk and coastal change are pulled out into a standalone chapter rather than sitting inside the wider climate change section. That is presentational on the face of it, but it reflects a shift in emphasis — flood risk treated as a primary constraint on where development goes, rather than one sustainability consideration among many.
Safe for its lifetime, or refused
The draft states more plainly that development which cannot be shown to be safe for its lifetime should be refused. The principle already exists; the drafting makes it harder to argue around.
Clearer triggers for flood risk assessments
More explicit requirements for site-specific flood risk assessments are proposed, including for development in Flood Zones 2, 3a and 3b, with defined triggers. In practice that would remove some of the current argument about whether an assessment is needed at all.
Explicit reference to national SuDS standards
The draft proposes referring directly to the national standards for sustainable drainage systems, with the aim of applying them consistently across the country. At the moment local standards vary considerably between authorities — as anyone who has designed in two neighbouring boroughs will know — and this is intended to narrow that gap.
What it would mean in practice
If it is adopted broadly as drafted, the practical effect is that more technical work moves earlier. Drainage and flood risk questions that are currently resolved at condition stage would need answering before permission, and in some cases before a site’s value is settled.
- Earlier cost. Assessment and percolation testing before permission rather than after it
- More certainty. Clearer rules cut both ways — fewer arguments, but fewer arguments available to you
- Some sites stop working. Marginal sites that currently get through on judgement may not under a more rules-based test
None of that is a reason to wait. Applications are being determined under the December 2024 Framework now, and a scheme designed properly against it is not made worse by a later change — the direction of travel is towards evidencing things that a sound design evidences anyway.
Which one applies to you
Today, the December 2024 Framework. If your application is likely to be determined some way off, it is worth designing with the draft’s direction in mind, because doing so costs little and removes a re-work risk. We will tell you which of those two situations you are in when we look at the site.
Sources: NPPF chapter 14 and the flood risk and coastal change guidance on GOV.UK. Page written September 2026 and reviewed when national policy changes.
Wondering whether you need separate SuDS approval? There is no SuDS Approving Body in England — despite what some council websites still say.