The Sequential and Exception Tests Explained (2026 Update)

Updated 17 August 2026. This guide has been rewritten for the new National Planning Policy Framework, which the Government published on 17 August 2026. The new Framework replaced the December 2024 version and changed how the sequential and exception tests work, so this article now follows Policies F5 and F6 rather than the old paragraph numbers.

The sequential and exception tests are the two planning-policy checks that decide whether new development can go ahead on land at risk of flooding. The sequential test comes first. It asks whether the scheme could be built somewhere at lower flood risk instead. The exception test only follows when a site cannot avoid the risk and the development still needs to be justified. Both sit in the National Planning Policy Framework, and because it was rewritten on that date, the paragraph numbers most guidance still quotes are now out of date.

This is a plain-English explainer of the two tests, not the service itself. If you need a Sequential Test or Exception Test prepared for a planning application, our Sequential Test and Exception Test reports page is where to go; this article is here to explain how the tests work.

Think of the two tests as one gateway with two gates. The sequential test tries to move development off flood-risk land altogether; the exception test is the narrower gate, for the schemes that genuinely cannot go anywhere else.

What are the sequential and exception tests?

The sequential and exception tests are national planning policy in England, applied when a proposal sits on land that could flood. The sequential test steers development towards the lowest-risk land available. The exception test is the second stage: where a higher-risk site cannot be avoided, it sets out what the applicant must prove for the development to be acceptable. They apply in that order, and the exception test is never reached until the sequential test has been worked through.

The tests apply in England only. In Wales the equivalent evidence is a flood consequence assessment under TAN15, not a sequential test against England's flood zones. You can look up any unfamiliar term, from functional floodplain to finished floor level, in our flood risk and drainage glossary.

The sequential test: steering development to lower-risk land

The sequential test asks a single question: is there a reasonably available site at lower flood risk that could take the development? If there is, the proposal should go there instead. The applicant defines an area of search, identifies the alternative sites within it, and compares them honestly on flood risk. Only then can they conclude that their own site is the right one.

Two things define how far the search has to reach. The area of search is now capped in policy at the development's own catchment, so a village shop or a GP surgery is measured against its local area rather than the whole district. And a site counts as a reasonable alternative even if the applicant does not own it, provided it could meet the same need in a similar timeframe.

The Government's own guidance for applicants sits behind the policy and explains how the comparison is expected to work. The flood zones themselves, from Zone 1 up to the functional floodplain, are covered in our guide to flood zones 1, 2 and 3.

The exception test: justifying development that cannot avoid flood risk

The exception test applies where the sequential test has shown there is no reasonably available lower-risk site, but the combination of flood zone and development type still needs further justification. Under the August 2026 Framework it is confined to flooding from rivers and the sea, and whether it bites is set by the vulnerability of the use against the flood zone.

To pass, a development now has to satisfy three separate limbs:

• Wider sustainability benefits. The development delivers benefits to the community that outweigh the flood risk, such as affordable housing, regeneration or needed infrastructure.
• Lifetime safety. It will be safe for its whole lifetime, taking account of the people who will use it and, now expressly, its visitors. For housing that lifetime is normally taken as at least 100 years.
• No increase in flood risk elsewhere. It does not raise flood risk on neighbouring land and, where possible, reduces it overall.

All three limbs have to be met, and the policy is now worded so that an incompatible use in the wrong flood zone should be refused rather than simply weighed in the balance.

The third limb is the genuinely new part. The old test had two limbs; the August 2026 Framework split out the "no increase elsewhere" requirement so it now has to be demonstrated on its own. Which uses need the test, and which face refusal outright, depends on the flood risk vulnerability classification, which we set out in our vulnerability classification guide.

How the two tests work together

The tests run in sequence, and most schemes never reach the second one. A site is only pulled into the exception test if it fails the sequential test and carries a use vulnerable enough, in a high enough flood zone, to need the extra justification. Read the flow from the top: the sequential test tries to relocate the development, and only what cannot be relocated, and is sensitive to flooding, meets the exception test's three limbs.

Take a worked example. A developer proposes housing on a site in Flood Zone 3a. The sequential test comes first: if a suitable, reasonably available site exists at lower flood risk nearby, the scheme should go there. If none is available, the sequential test is satisfied on that evidence. Housing is a "more vulnerable" use, and in Flood Zone 3a that combination triggers the exception test. So the developer then has to show the three limbs are met: real community benefits, lifetime safety with climate change built in, and no added flood risk elsewhere. Clear all of that, and the scheme stands on flood-risk grounds.

What changed for the two tests in the August 2026 NPPF

The August 2026 Framework rewrote the flood chapter, moving the two tests out of the old paragraphs 173 to 180 and into Policies F5 and F6. The substance largely carried over, but four changes matter for how the tests are argued. Our full analysis of the August 2026 NPPF changes works through the whole flood chapter; the ones that touch the two tests directly are these.

• The area of search is capped. The sequential test search should not be greater than the development's anticipated catchment, a firmer limit than the old proportionality wording.
• Surface water alone can now be exempt. Where a site is at risk of surface water flooding only, the sequential test falls away if the flood risk assessment shows the development will be safe for its lifetime without increasing risk elsewhere.
• The exception test has a third limb. The "no increase in flood risk elsewhere" requirement is now a free-standing test, and the exception test is confined to river and sea flooding.
• Refusal wording replaces permissive wording. Incompatible uses in the wrong flood zone should be refused, rather than merely weighed, which raises the value of getting the evidence right the first time.

These changes apply to every application decided from 17 August 2026, including those already submitted, and our NPPF flood risk guidance keeps the current position in one place.

Do the tests apply to your development?

The sequential test is normally required where a proposal sits on land at flood risk from any source and no exemption applies, most commonly a site in Flood Zone 2 or 3, or one flagged for surface water. The exception test only follows for certain vulnerable uses in higher-risk zones. Several proposals are exempt from both: householder development, small non-domestic extensions under 250 square metres, most changes of use, and sites allocated in an up-to-date Local Plan where the test was applied at allocation.

Needing a sequential test does not mean a site is undevelopable; it means the authority needs evidence that no reasonably available lower-risk site could take the scheme, and that evidence can be assembled and argued properly.

If you are not sure whether a test applies, our guide on when you need a flood risk assessment works through the common cases, and you can screen a site yourself on our free flood risk map postcode checker.

If your development needs the tests worked up into evidence a planning authority can rely on, our sequential and exception test reports are prepared as one coordinated package with the flood risk assessment for planning. Send us the site and the proposal and we will tell you whether a test is actually required, and quote within the hour.

Frequently asked questions