What Are The Sequential And Exception Tests?

The sequential test and the exception test are the two national policy tests that steer development away from land at risk of flooding in England. The sequential test (National Planning Policy Framework Policy F5) asks whether the same development could go on a reasonably available site at lower risk of flooding from any source. The exception test (Policy F6) applies only in river and sea Flood Zones 2, 3a and 3b, where Annex F, table 3 requires it, and since 17 August 2026 it has three parts, not two. Aegaea prepares both, together with the flood risk assessments that support them.

What Is The Sequential Test?

The sequential test is a site-selection test in England’s planning system. It steers new development towards land at the lowest risk of flooding by asking whether the same development could reasonably be built on another available site at lower risk. Under Policy F5(1) of the NPPF (August 2026), its aim is “to steer new development to areas with the lowest risk of flooding from any source”. It therefore covers rivers, the sea, surface water, groundwater, sewers and reservoirs, not only Flood Zones 2 and 3.

The test is applied at two stages. The local planning authority applies it when it allocates sites in a local plan. For planning applications on sites that were not allocated and tested in that way, it is applied to the individual application.

Who does what. Planning Practice Guidance (paragraph 029) splits the roles. The local planning authority determines the area of search. The applicant identifies whether there are any other reasonably available sites within it, beyond those the council has already identified in its site allocations and land availability assessments. The decision maker decides whether the test is passed. In practice, the applicant’s flood risk consultant or planning consultant prepares the sequential test report, and the council or, on appeal, the planning inspector decides.

Policy F5(3) says the council’s strategic flood risk assessment (SFRA) and the Environment Agency’s Flood Map for Planning should provide the evidential basis for the test.

Do I need a sequential test?

You need a sequential test for development in an area at current or future risk of flooding from any source, unless one of the exemptions in Policy F5(2) of the August 2026 NPPF applies. There are six routes to exemption. The table sets out each one.

Do you need a sequential test? (NPPF Policy F5(2))

Case study: no sequential test needed in Lewisham. The council’s pre-application advice on a Flood Zone 2 site said a sequential test would be required. Our flood risk assessment used detailed flood model outputs to show the site was at low risk from all sources of flooding, the council agreed that no sequential test was needed, and planning permission was granted. Read the Lewisham case study.

Exemption from the sequential test is not exemption from a flood risk assessment. In England a site-specific flood risk assessment should accompany all development proposals in Flood Zones 2, 3a and 3b (Policy F4(1)). In Flood Zone 1, Policy F4(2) says one should inform and accompany “all development proposals involving: (a) Sites of one hectare or more; (b) Land which has been identified by the Environment Agency as having critical drainage problems; and (c) Land identified in a strategic flood risk assessment or the Flood Map for Planning as being at risk of flooding from any source, whether now or in the future.” Any one of these is enough to need a flood risk assessment. Footnote 55 to F4(2)(c) names the Flood Map for Planning as the Environment Agency’s online service at flood-map-for-planning.service.gov.uk. Planning Practice Guidance (paragraph 051) adds that for minor extensions “a shorter, simpler assessment is likely to be sufficient in most such cases”. Our minor developments page explains what that shorter assessment covers.

Flood Zone 1 is not the end of the question. Flood Zones 2 and 3 cover rivers and the sea only. Annex F of the NPPF says they “only account for river and sea flooding, and do not account for the benefits of flood defences or the possible effects of climate change”, and that “reference should therefore also be made to the Environment Agency’s other data on the Flood Map for Planning, and any current strategic flood risk assessment(s), when considering potential future flood risks to developments and land uses”. The Flood Map for Planning now shows both main sources for the present day and with climate change:

• Rivers and the sea: Flood Zones 2 and 3, and, since 27 August 2025, Flood Zones plus climate change.
• Surface water (risk of flooding from surface water): present-day extents since March 2025 and, since 28 May 2026, spatial planning extents and depths with climate change.

So a site in Flood Zone 1 for rivers and the sea can still need a flood risk assessment under F4(2)(c) if any of these layers, or the council’s strategic flood risk assessment, shows it at risk now or in the future. The same evidence decides the sequential test, which applies “in areas known to be at risk now or in the future from any form of flooding” (Policy F5(2)), with the strategic flood risk assessment and the Flood Map for Planning as its evidence base (Policy F5(3)).

Check the date of the strategic flood risk assessment. A strategic flood risk assessment is a live document: Policy F1 expects plans to be informed by “an up-to-date strategic flood risk assessment which considers current and future flood risk from all sources”. Many were prepared before the Environment Agency’s 2025 and 2026 mapping updates. Where the council’s assessment is out of date, the Flood Map for Planning should generally be relied on, and that is the approach we take.

In its May 2026 briefing for developers and flood risk consultants, the Environment Agency said the new surface water datasets “may trigger a new requirement for a flood risk assessment and sequential test (exemptions apply)”. A site that is clear of the flood zones today can still need both if it is at risk from surface water, or from rivers and the sea with climate change.

Not sure which row you are in? Send us the site address and what you plan to build. We’ll tell you whether either test applies - free and without obligation.

How do you carry out a sequential test?

A sequential test for a planning application in England follows five steps. It can be presented in any format, but in our experience planning officers and inspectors expect each step to be visible, sourced and dated.

1. Agree the area of search. Under Policy F5(1) the area of search “should not be greater than the anticipated catchment of the development in terms of its likely occupiers or users”. Because the council determines the area of search (PPG paragraph 029), agree it with the planning officer before you start. Planning Practice Guidance (paragraph 027a) says the catchment should always be appropriate to the nature and scale of the proposal, and that for non-major housing it would not usually be appropriate to search beyond the town or city, or beyond the village and its immediate neighbouring settlements.
2. Identify alternative sites. Start with the sites the council already knows about: site allocations and housing or economic land availability assessments. Then add sites that are not in those documents, such as sites currently available on the open market, and, where needed, check each site’s current status (PPG paragraph 029). Some councils keep a register of reasonably available sites ranked by flood risk.
3. Decide which sites are reasonably available. Planning Practice Guidance (paragraph 028) says a site is reasonably available if its location is suitable for the type of development, it can meet the same development needs, and it has a reasonable prospect of being developed at the same time as the proposal. Where relevant, an alternative can be a series of two or more smaller sites, and it does not need to be owned by the applicant.
4. Compare flood risk from all sources, now and in the future. Compare each reasonably available site with the application site on the same basis: flood zone, surface water, groundwater, sewers, reservoirs and climate change. Planning Practice Guidance (paragraph 024) says to look first for sites in low-risk areas, then medium-risk, then high-risk, and initially to ignore existing flood defences, because their long-term funding, maintenance and renewal is uncertain.
5. Reach and record a conclusion. Policy F5(1) says 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”. If no such site exists, the test is passed and the proposal moves on to the exception test (if table 3 requires it) and to Policy F7.

How proportionate should a sequential test be?

Planning Practice Guidance (paragraph 027a, revised September 2025) asks for the test to be applied proportionately, “focusing on realistic alternatives in areas of lower flood risk that could meet the same development need”. It gives four practical pointers:

• Extensions that are small relative to the existing premises: take a pragmatic approach where it may be impractical to put the extra space anywhere else.
• Towns built in the floodplain: where large areas are in Flood Zones 2 and 3, such as coastal towns and settlements on major rivers, and development is needed there to sustain the community, sites outside them are unlikely to be reasonable alternatives.
• Regional or national infrastructure: the area of search may reasonably extend beyond the local planning authority boundary.
• Large schemes: splitting a development across several lower-risk sites is relevant only where those sites would still serve the intended market as effectively.

Paragraph 027 adds that the absence of a five-year housing land supply “is not a relevant consideration in applying the sequential test for individual applications”, although housing land supply may be relevant in the planning balance alongside the outcome of the test.

What planning officers look for

In our experience of sequential tests that succeed and fail, officers and inspectors focus on the same few things:

• an area of search that is justified by the development’s actual catchment and agreed with the council, not chosen to exclude competing sites;
• site sources that are named and dated, so the search can be repeated;
• the same flood risk measures applied to every site, including surface water and future risk;
• a clear, reasoned note for every site discounted, not a single sentence for the whole list.

What happens if a development fails the sequential test?

Failing the sequential test means the proposal conflicts with Policy F5 of the NPPF, and councils can and do refuse permission on that ground. But a sequential test that is failed, or was never done, does not decide the application on its own. The decision maker still has to weigh the conflict with policy against all the other material considerations, and two High Court judgments in 2026 confirmed that this applies to the sequential test.

• Gladman Developments Ltd v SSHCLG and Lancaster City Council [2026] EWHC 51 (Admin), 15 January 2026. Lieven J quashed an inspector’s decision dismissing Gladman’s appeal for up to 644 homes at Bailrigg Lane, Lancaster. The inspector had treated the lack of a sequential assessment as fatal without weighing it against the other considerations, which the judge called “an inflexible and mechanistic approach”.
• North Somerset DC v SSHCLG and Persimmon Homes Severn Valley [2026] EWHC 1430 (Admin), 12 June 2026 (the Yatton case). Jefford J upheld an appeal decision granting 190 homes at Rectory Farm, Yatton, even though the sequential test was failed. The inspector “should not stop once the sequential test is not passed but should continue to take into account material considerations”, and could weigh the factors that make up the exception test as part of that balance.

Both cases were decided under earlier versions of the Framework, before Policy F5 existed (Gladman under the version in force in November 2024, Yatton under the December 2024 Framework), but they rest on the statutory duty to decide applications in accordance with the development plan unless material considerations indicate otherwise. A failed test still weighs heavily, so the stronger strategy is almost always to pass it, or to design the scheme so that an exemption applies.

Mead Realisations Ltd v SSHCLG [2025] EWCA Civ 32 (Court of Appeal, 30 January 2025) concerned what “reasonably available” means. The court upheld the inspector’s decision, described reasonably available as “an elastic concept”, and held that the 2022 Planning Practice Guidance on it, including that lower-risk sites need not be owned by the applicant, clarified the policy then in force (NPPF 2021, paragraph 162) rather than adding requirements to it. The guidance was reworded in September 2025, but the ownership point is materially the same.

Case study: a sequential test after a legal challenge in Southwark. For Leathermarket Community Benefit Society’s community-led housing in Southwark (SE1), a legal challenge had found that flood risk policy had not been properly considered, sending the scheme back to the drawing board. We agreed the sequential test methodology with Southwark Council’s planning and legal officers before carrying out the assessment, to show robust compliance with national and local flood risk policy and reduce the risk of a later judicial review. Read the Leathermarket case study.

What is the exception test?

The exception test is the second flood risk test in England’s NPPF. It applies only in Flood Zones 2, 3a and 3b, which Annex F, table 1 defines by river and sea flooding, and only where Annex F, table 3 says the use needs it in that zone. Policy F6 is headed “Development in areas at risk of flooding from rivers or the sea”. A site at risk only from surface water, groundwater or another source does not need the exception test under the NPPF, although Policy F7 still applies. Development that is incompatible with its flood zone under table 3 should be refused (Policy F6(1)(a)).

Under Policy F6(1)(b) of the August 2026 NPPF, the exception test has three parts, and all must be met. It must be shown that the development will:

1. “Provide wider sustainability benefits to the community that outweigh the flood risk”;
2. “Be safe for its anticipated lifetime in accordance with policy F7”; and
3. “Not increase flood risk elsewhere and, where possible, reduce flood risk overall.”

The third part is now a separate criterion. Under the previous Framework, not increasing flood risk elsewhere sat inside the safety limb, so reports should now address it under its own heading.

When the exception test does not apply. Under Policy F6(2) it is not needed where the sequential test is not required under Policy F5. Nor is it needed on a site allocated in the development plan where the exception test was applied at plan-making stage, unless the flood risk has significantly increased since, or the development has changed significantly from the allocation so as to introduce a more vulnerable use. At application stage the exception test should be informed by a site-specific flood risk assessment; at plan-making stage, by an up-to-date SFRA (footnote 56).

Incompatible uses. Policy F6(1)(a) says that in Flood Zones 2, 3a and 3b, “development proposals should be refused if the use is incompatible with the risk from river or sea flooding, as set out in Annex F, table 3”. Table 3 marks these combinations “No” (see the table below).

What evidence passes each part?

Evidence for each part of the exception test (NPPF Policy F6(1)(b); Aegaea practice)

The flood zone compatibility table (Annex F, table 3)

Annex F, table 3 of the NPPF (August 2026) shows, for each flood zone and each vulnerability class, whether development is compatible, needs the exception test, or should be refused. In the table, “Yes” means the exception test is not required, and “No” means development should be refused. The † and †† marks point to the notes below the table (the PDF version of the Framework uses * in place of ††). Table 3 does not replace the sequential test, which still applies unless an exemption does.

NPPF Annex F, table 3 – Flood risk vulnerability and flood zone ‘incompatibility’

Notes to table 3, as published:

• † “In flood zone 3a essential infrastructure should be designed and constructed to remain operational and safe in times of flood.”
• †† In Flood Zone 3b, essential infrastructure that has passed the exception test, and water-compatible uses, should be designed and constructed to remain operational and safe for users in times of flood, result in no net loss of floodplain storage, and not impede water flows or increase flood risk elsewhere.
• Where a development has elements in different vulnerability classes, “the highest vulnerability category should be used, unless the development is considered in its component parts.”

Which vulnerability class is my development?

Annex F, table 2 sets out the five classes. These are the most common examples:

For the full list of essential infrastructure and what changed in 2026, see our flood risk assessment for essential infrastructure page.

What does “safe for its lifetime” mean?

Policy F7 of the NPPF (August 2026) applies to development at risk from any form of flooding, now or in the future, not only in the river and sea flood zones. It says such development “should be refused unless”:

• within the site, the most vulnerable development is in the areas of lowest flood risk, unless there are overriding reasons for a different arrangement;
• the development will be safe throughout its lifetime, taking account of the vulnerability of its users;
• any residual risk can be safely managed, with safe access and escape routes where appropriate, as part of an agreed emergency plan;
• the development is flood resistant and resilient enough to be brought back into use quickly after a flood, without significant refurbishment; and
• flood risk will not be increased elsewhere.

Sustainable drainage has its own policy, F8. Proposals that could affect drainage should incorporate sustainable drainage systems, in proportion to the scheme, designed in accordance with the National Standards and maintained for the lifetime of the development. See surface water drainage.

An agreed emergency plan for residual risk is often a Flood Warning and Evacuation Plan (FWEP).

Four worked examples

These are illustrative scenarios showing how Policies F4 to F7 apply. Every real site needs its own assessment.

A rear extension to a house in Flood Zone 3a. This is householder development, so no sequential test is needed, whatever its size (F5(2)(c)(i)). Because the exception test does not apply where the sequential test is not required (F6(2)(a)), it is not needed either. A flood risk assessment is still required in Flood Zone 3a (F4(1)), but a shorter, simpler one is likely to be sufficient.

Converting offices to flats in Flood Zone 2. A change of use is exempt from the sequential test unless it is to a caravan, camping, chalet, mobile home or park home site (F5(2)(c)(iii)), so neither test applies. The change from offices (less vulnerable) to dwellings (more vulnerable) raises the vulnerability of the building (PPG paragraph 014), so the flood risk assessment must show the flats will be safe, typically through floor levels, access and escape, and an emergency plan. If the conversion is under permitted development, see our permitted development page.

Nine new homes on an unallocated site in Flood Zone 1 with a surface water flow path. The sequential test applies, because the site is at risk from a source of flooding. But if the flood risk assessment demonstrates clearly that no building, access or escape route, land raising or other vulnerable element will be in an area at risk now or in the future, including the surface water with climate change extent, the site is exempt under F5(2)(b)(i). Because the risk is from surface water only, the F5(2)(b)(ii) route may also be open where layout, design and mitigation keep occupiers safe. The exception test never applies, because the site is outside Flood Zones 2 and 3. In our experience, getting the layout right before the application is often cheaper than running a full sequential test.

Case study: designing out the sequential test in Ilford. At Capital Gate, Ilford, a residential site in Flood Zone 1 within a Critical Drainage Area and at risk of surface water flooding, we built a site-specific surface water flood model and worked on the layout so that the homes sit in the lowest-risk areas, with surface water flooding in the 1% and 0.1% annual probability events directed into open space, biodiversity and amenity areas. A site sequential test was not needed. Read the Ilford case study.

120 homes on an unallocated edge-of-town site in Flood Zone 3a. The sequential test applies, with an area of search agreed with the council and no larger than the scheme’s housing catchment. If no reasonably available lower-risk site can meet the same need, the test is passed, and table 3 then requires the exception test for more vulnerable development in Zone 3a. That needs a planning case for the wider sustainability benefits, and a flood risk assessment, usually with hydraulic modelling and floodplain compensation, showing the homes will be safe for their lifetime and will not increase flood risk elsewhere. A housing land supply shortfall does not change the sequential test, but it may weigh in the planning balance.

What changed in August 2026?

The NPPF published on 17 August 2026 restructured flood risk policy. Its policies have been material considerations in planning decisions since the day of publication (Annex A, paragraph 1), and Annex A contains no transitional arrangement for planning applications already submitted. For the sequential and exception tests, these are the main changes:

• Flood risk and coastal change is now Chapter 18, Policies F1 to F9. Chapter 14 is now design policy.
• The flood zone definitions (table 1), vulnerability classification (table 2) and compatibility table (table 3) are all in Annex F of the Framework. Annex 3 no longer exists.
• The sequential test is Policy F5 and the exception test is Policy F6. Flood risk policy no longer uses the old running paragraph numbers (such as 173 to 182); it is now Policies F1 to F9, with numbered sub-paragraphs.
• The exception test has three parts, not two.
• The exemptions from the sequential test are set out in one place, F5(2). The surface-water-only route, which also appears in Planning Practice Guidance (paragraph 027, revised September 2025), is now in policy.
• Annex C lists a site-specific flood risk assessment and a statement of how the national SuDS standards have been met as national information requirements.

Our article on the new NPPF and flood risk explains the wider changes.

The guidance has not caught up with the Framework

Practitioners still rely on guidance written before August 2026. At the time of writing, in October 2026:

• Planning Practice Guidance on flood risk was last updated on 17 September 2025. It still refers to NPPF paragraphs 173 to 176 and 180, to footnote 55 as the flood risk assessment trigger, and to “Annex 3”. Paragraph 035 still describes “both elements” of the exception test, which now has three.
• Two different 250 m² tests. Planning Practice Guidance (paragraph 051) defines minor non-residential extensions by floorspace “not in excess of 250 square metres”. Policy F5(2)(c)(ii) uses a footprint “of less than 250m2”. Footprint is the area of ground the extension covers; floorspace adds up every storey, so for a two-storey extension the answers can differ. In our view the policy wording governs the sequential test exemption, because PPG 051 defines minor development for flood risk assessment purposes. We confirm the approach with the council early.
• Environment Agency guidance: the climate change allowances guidance was last updated on 27 May 2022, and the flood risk standing advice, updated 28 May 2026, still links to Annex 3 and still refers to “both elements” of the exception test.

Where guidance and the Framework now differ, our reports apply the Framework and explain the difference, so the planning officer does not have to.

How do the tests work in Wales and Scotland?

The sequential and exception tests are English policy. Wales and Scotland control development in flood risk areas differently.

Sequential and exception tests: England, Wales and Scotland compared (Aegaea summary)

For Welsh sites, see our Flood Consequences Assessments in Wales page.

How Aegaea can help

If you are a homeowner or self-builder, we will tell you whether your project is exempt, and produce the flood risk assessment the council needs, typically in 5 to 10 working days once we have the data.

If you are a planning consultant, architect or developer, we prepare sequential test reports to your brief, agree and justify the area of search, and evidence parts 2 and 3 of the exception test through site-specific flood risk assessments, hydraulic modelling and drainage strategies. We also support planning appeals. We work with you from the layout stage, when designing out flood risk is cheapest.

Every Aegaea report is reviewed and signed off by a Chartered member of CIWEM. We have supported over 1,000 projects.

Send us the site address and what you plan to build. We’ll tell you whether either test applies. Contact us or call 020 8156 6076.

Sequential and exception test FAQs