The Flood Risk Sequential Test Under the NPPF 2026
The sequential test under NPPF 2026 has been rewritten in a way that genuinely helps applicants, and almost nobody is using it yet. Policy F5 of the August 2026 National Planning Policy Framework now caps the geographical area over which alternative sites must be searched — a limit that did not exist in December 2024 — and adds a new exemption route for sites at risk from surface water only. It also carries a trap, because being exempt from the sequential test is not the same as being exempt from the policy that decides whether your development is safe. Here is how F5 now works.
What the sequential test is, and what F5 sets out to do NPPF 2026
F5(1) states the purpose: "The aim of the sequential test is to steer new development to areas with the lowest risk of flooding from any source. Where the test applies, development proposals should not be located in areas at risk of flooding where alternative sites, appropriate for the development, are reasonably available in areas with a lower risk of flooding."
Three qualifiers carry the weight. Sites must be alternative, they must be appropriate for the development, and they must be reasonably available. A site that could not accommodate the scheme, or that is not on the market and shows no realistic prospect of becoming available, is not a reasonably available alternative. The test is comparative, not aspirational.
Note also that F5 is framed around risk "from any source". It is not a rivers-and-sea test. Surface water, groundwater and other sources are within scope, which is a change of emphasis worth carrying into how you frame the assessment.
The biggest change: the area of search is now capped
December 2024 paragraph 174 said: "Development should not be allocated or permitted if there are reasonably available sites appropriate for the proposed development in areas with a lower risk of flooding. The strategic flood risk assessment will provide the basis for applying this test."
It said nothing about how large an area you had to look at. That silence caused years of argument. Applicants proposed a ward or a village; officers came back with the whole administrative area; occasionally an authority pushed for a region.
F5(1) closes the gap with a sentence that has no equivalent in December 2024: "The area to which the test is applied should not be greater than the anticipated catchment of the development in terms of its likely occupiers or users."
This is a relaxation, and it is the single most useful change in Chapter 18 for anyone trying to keep a scheme in a lower-risk location argument. The area of search is now defined by who the development is for, not by administrative convenience. In practice:
A single self-build or replacement dwelling for an identified household has an anticipated catchment measured in streets, not districts.
A local convenience store or nursery draws from a walkable neighbourhood.
A care home with a local admissions policy draws from the settlement and its immediate surrounds.
A regional distribution shed genuinely does have a wide catchment, and F5(1) will not shrink it.
The evidential burden runs with the claim. If you say the catchment is a 1 km radius, you need something behind it — the client's household circumstances, an existing customer or membership base, a school or employment catchment, comparable trade area evidence. Our view, and it is our view rather than policy, is that authorities will resist narrow catchments at first and that the arguments that succeed will be the ones with documented evidence of who the occupiers or users actually are. Assert a catchment without support and you have handed the officer a reason to widen it.
The routes out of the sequential test at F5(2)
F5(2) requires the sequential test in areas known to be at risk now or in the future from any form of flooding, "other than for" four categories.
Allocated sites — F5(2)(a)
"Sites allocated in the development plan which were subject to the sequential test during plan preparation." Check that the allocation was in fact sequentially tested at plan stage; the exemption is conditional on it, and the plan's own evidence base will show whether it was.
No built development at risk — F5(2)(b)(i)
Where a site-specific flood risk assessment demonstrates clearly that "no built development within the site boundary, including access or escape routes, land raising or other potentially vulnerable elements, would be located on an area that would be at risk of flooding from any source, now and in the future". This route existed in December 2024 at paragraph 175 and is essentially carried forward. It is exacting: access, escape routes and land raising all count, so a dwelling on a dry platform served by a road that floods does not qualify.
The new surface water route — F5(2)(b)(ii)
This one is new. Where the site "would be at risk of surface water flooding only", the exemption applies if "the proposed layout, design, and mitigation measures would ensure that occupiers and users would remain safe from current and future surface water flood risk for the lifetime of the development without increasing flood risk elsewhere in accordance with policy F7."
There was no equivalent in December 2024. Under the old wording, a site in Flood Zone 1 with a mapped surface water flow path could be dragged into a sequential test with no clean way out. F5(2)(b)(ii) provides one.
The conditions are tight, and each is a separate test:
"Surface water flooding only." Any material risk from rivers, the sea, groundwater, sewers or reservoirs closes this route. You have to evidence the absence, not assume it.
Layout, design and mitigation, not just mitigation. The exemption is earned by how the scheme is arranged — levels, thresholds, the position of vulnerable rooms, the location of flow routes kept clear — as much as by drainage.
Current and future risk, for the lifetime of the development. That means applying Environment Agency peak rainfall intensity allowances for surface water and small urban catchments, for the relevant epoch, over a design life of 100 years for residential or 75 years for non-residential development per Planning Practice Guidance.
Without increasing flood risk elsewhere, in accordance with policy F7. The route is expressly tied back to F7, which is the point of the next section.
Householder, small extensions and changes of use — F5(2)(c)
The sequential test is not required for:
(i) "Householder development";
(ii) "Small non-residential extensions (with a footprint of less than 250m2)"; and
(iii) "Changes of use, other than changes of use to a caravan, camping or chalet site, or to a mobile home or park home site."
December 2024 handled this differently. Paragraph 176 said that "applications for some minor development and changes of use should also not be subject to the sequential test, nor the exception test set out below, but should still meet the requirements for site-specific flood risk assessments", and left the actual definition in footnote 62. Now the categories sit in the policy body itself, which makes them harder to argue about at the margins, and the carve-out for caravan, camping, chalet, mobile home and park home sites is stated in the policy rather than tucked away.
Exemption from the sequential test is not exemption from F7
This is the point that costs applicants permissions, so it is worth stating flatly.
F5(2)(c) exempts householder development from the sequential test. F6(2)(a) then disapplies the exception test for anything where the sequential test is not required. Both of those are real. Neither of them touches policy F7.
F7(1) requires that development proposals "should not present a risk from flooding to potential occupiers, users, or visitors, and should not increase flood risk elsewhere." F7(2) provides that where development is proposed in a location known to be at risk from any form of flooding, now or in the future, "it should be refused unless" five limbs are satisfied — including F7(2)(e), "it can be demonstrated that flood risk will not be increased elsewhere."
There is no householder exemption in F7. So the sentence we hear constantly — "it's a householder extension, so the sequential test doesn't apply" — is true and does not get the application approved. An extension built in the floodplain displaces flood water into the surrounding area. That is a loss of flood storage and it engages F7(2)(e) directly. Planning Practice Guidance expects on-site level-for-level compensatory storage where flood storage from any source is lost, accounting for climate change over the lifetime of the development.
We are seeing this decided against applicants now: small extensions in Flood Zone 2 and 3, and in areas of high surface water risk, refused because no compensation was offered and no displaced volume was ever calculated. A Planning Inspectorate appeal decision has given significant weight to the Environment Agency's objection as statutory consultee and to the cumulative effect of many similar small developments in Flood Zone 3 each being permitted without compensation. The flood risk assessment is where that arithmetic belongs.
Note too that the December 2024 wording at paragraph 176 already said exempt schemes "should still meet the requirements for site-specific flood risk assessments". The August 2026 structure keeps that: F4(1) requires an FRA for all proposals in Flood Zones 2, 3a and 3b, with no exemption for householder development.
How F6 connects the exception test to F5
F6(1)(a) requires refusal in Flood Zones 2, 3a or 3b where "the use is incompatible with the risk from river or sea flooding, as set out in Annex F, table 3". F6(1)(b) requires the exception test in the other circumstances Table 3 identifies, in addition to the sequential test where applicable, and now sets three criteria rather than two: wider sustainability benefits to the community that outweigh the flood risk; safety for the anticipated lifetime in accordance with policy F7; and no increase in flood risk elsewhere, reducing it overall where possible.
December 2024 paragraph 178 had two limbs, with safety and the no-increase requirement bundled together in limb (b). Splitting them into F6(1)(b)(ii) and (iii), and tying limb (ii) to F7, means each has to be evidenced on its own terms.
F6(2) then sets out when the exception test is not needed: where the sequential test is not required under F5, or where the site is a plan allocation to which the exception test was applied at plan-making stage — the latter "unless there has been a significant increase in the risk of flooding to the site subsequently, or the nature of the development itself has changed significantly from that which was allocated so as to introduce a more vulnerable use". If you are relying on an allocation, check both conditions, because updated flood mapping or a change from commercial to residential use will reopen the test.
Because Annex F, Table 3 is now inside the Framework and paragraph 9 confirms that "the annexes included with this Framework are also national planning policy", the incompatibility matrix that decides whether you need the exception test at all carries policy status rather than guidance status. Our note on the sequential and exception tests sets out how the two run together on a live application.
Evidence: what F5(3) expects
F5(3) states that "the strategic flood risk assessment covering the area of the proposed development and the Flood Map for Planning should provide the evidential basis for applying the sequential test."
December 2024 paragraph 174 named only the SFRA. Adding the Flood Map for Planning is sensible, because SFRAs date quickly and mapping is updated more often. Use both, and record the date of the data you relied on. Where the two disagree, say so and explain which you have followed. Remember the note to Annex F, Table 1: Flood Zones 2 and 3 "only account for river and sea flooding, and do not account for the benefits of flood defences or the possible effects of climate change." Screening alternative sites on flood zone alone will not address risk from other sources, which is what F5(1) asks about.
How to build a sequential test that stands up
Check the exemptions first. Run through F5(2)(a), (b)(i), (b)(ii) and (c) before doing any site searching. If F5(2)(c)(i) or (ii) applies, say so in one paragraph with the policy reference and move on.
If you are relying on F5(2)(b)(ii), evidence the "surface water only" premise. Rule out river, sea, groundwater, sewer and reservoir sources with named data sources, then show layout, design and mitigation delivering safety for the design life.
Define the area of search explicitly, and justify it under F5(1). State the anticipated catchment, state who the likely occupiers or users are, and attach the evidence. Agree it with the case officer before you search if you can.
Set the site requirements honestly. Size, use, access, deliverability and timescale. Requirements written to exclude every alternative will be seen for what they are.
Search with a dated, reproducible method. Portal listings, agent enquiries, the SHLAA or brownfield register, plus council allocations, with the search date and search terms recorded.
Flood-zone every candidate and record why each is not reasonably available or not appropriate. One reason per site, evidenced.
Do not stop at the sequential test. Carry on into F6 where Table 3 requires the exception test, and into F7 in every case, including the F7(2)(e) demonstration on flood risk elsewhere. If your development sits in the floodplain, quantify the displaced volume in m³ and set out the compensation.
Cite precisely. F5(1), F5(2)(c)(ii), F6(2)(b), Annex F Table 3. Paragraph-level citation is what makes an assessment easy for an officer to agree with.
Where drainage design is part of the answer, our SuDS page covers the Defra national standards, and where safe access and egress is in issue, see flood evacuation plans.
Frequently asked questions
How large does the area of search have to be?
F5(1) provides that the area "should not be greater than the anticipated catchment of the development in terms of its likely occupiers or users." There is no fixed radius. A single dwelling for a named household and a regional logistics unit will have very different catchments, and the evidence you provide about who will occupy or use the development is what sets it.
Does a householder extension need a sequential test?
No. F5(2)(c)(i) exempts householder development, and F6(2)(a) therefore also removes the exception test. It does not remove the requirement for a site-specific flood risk assessment under F4(1) in Flood Zones 2, 3a and 3b, and it does not remove policy F7, which is worded as a refusal unless all five limbs of F7(2) are met.
What counts as a "reasonably available" alternative site?
A site that could accommodate the proposed development and could realistically be acquired and brought forward. Sites that are not on the market, are in fragmented ownership with no prospect of assembly, or are too small or constrained for the scheme, are generally not reasonably available — but you must evidence that rather than assert it, site by site.
Can I use the surface water exemption on a site partly in Flood Zone 2?
F5(2)(b)(ii) applies where the site "would be at risk of surface water flooding only". A site with any part in Flood Zone 2 is identified as at risk from rivers or the sea, so on the wording that route is unlikely to be available. F5(2)(b)(i) may still be, if a site-specific FRA can show that no built development, access or escape route would be at risk from any source now or in the future.
If you need an area of search agreed, an exemption argued under F5(2), or a full sequential test with a site comparison matrix that an officer can follow, we do this work every week across England. Get a quote with the site address, the flood zone and a brief description of the scheme, and we will tell you whether a sequential test is required before you spend anything on one.
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