Flood risk PPG update: Sequential test clarified
Just like water, planning regulations and policy rarely stand still, and the September 2025 update to the Planning Practice Guidance on flood risk and coastal change (“PPG”) is a good example of this. If you have ever had issues with identifying “reasonably available” sites or had to deal with sequential tests for developments, this update is for you.
Background: why the change, and why now?
The update to the PPG does not come out of the blue.
The December 2024 revision of the National Planning Policy Framework (“NPPF”) had already signalled that further clarification was coming in relation to how to consider “reasonably available sites” and the role of site-specific Flood Risk Assessments (“FRAs”).
The update was also motivated by the recent ruling of the Court of Appeal in Mead Realisations Ltd v Secretary of State for Housing, Communities and Local Government [2025] EWCA Civ 32, as it clarified that the legal status of the Government's planning policies in the NPPF and its guidance in the PPG is basically the same, and highlighted the need for clearer guidance on “reasonably available sites”.
From a practical point of view, while the Sequential Test is a cornerstone of flood risk planning, designed to steer development towards areas of lowest flood risk, it has been criticised for being overly rigid, especially in cases where technical evidence could demonstrate that a site was safe despite its flood zone classification. Developers and local planning authorities alike have struggled with inconsistent interpretations of the “area of search” and what counts as a “reasonably available” alternative.
Changes to the PPG
The update amends paragraphs 23, 27 and 28 of the PPG. Also, a new paragraph 27a was inserted.
Paragraph 23: This paragraph remained largely unchanged, with only the following part removed from it.
“What is the aim of the sequential approach?
The approach is designed to ensure that areas at little or no risk of flooding from any source are developed in preference to areas at higher risk. This means avoiding, so far as possible, development in current and future medium and high flood risk areas considering all sources of flooding including areas at risk of surface water flooding. Avoiding flood risk through the sequential test is the most effective way of addressing flood risk because it places the least reliance on measures like flood defences, flood warnings and property level resilience features. Even where a flood risk assessment shows the development can be made safe throughout its lifetime without increasing risk elsewhere, the sequential test still needs to be satisfied. Application of the sequential approach in the plan-making and decision-making process will help to ensure that development is steered to the lowest risk areas, where it is compatible with sustainable development objectives to do so, and developers do not waste resources promoting proposals which would fail to satisfy the test. Other forms of flooding need to be treated consistently with river and tidal flooding in mapping probability and assessing vulnerability, so that the sequential approach can be applied across all areas of flood risk.”
Paragraph 27: This paragraph was entirely replaced, and now provides the following.
How should the sequential test be applied to planning applications?
See advice on the sequential approach to development and the aim of the sequential test.
The sequential test should be applied to ‘Major’ and ‘Non-major’ development proposed in areas at risk of flooding, as set out in paragraphs 173 to 174 of the National Planning Policy Framework. Paragraphs 175, 176 and 180 set out exemptions from the sequential test.
In applying paragraph 175 a proportionate approach should be taken. Where a site-specific flood risk assessment demonstrates clearly that 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 (therefore addressing the risks identified e.g. by Environment Agency flood risk mapping), without increasing flood risk elsewhere, then the sequential test need not be applied.
The absence of a 5-year housing land supply is not a relevant consideration in applying the sequential test for individual applications. However, housing considerations, including housing land supply, may be relevant in the planning balance, alongside the outcome of the sequential test.
See also advice on who is responsible for deciding whether an application passes the Sequential Test and further advice on the Sequential Test process available from the Environment Agency (flood risk standing advice).
Paragraph 27a: This paragraph is entirely new and reads as follows.
How should the area of search for the sequential test be identified?
For individual planning applications subject to the sequential test, the area to which the test needs to be applied will be governed by local circumstances relating to the catchment area for the type of development proposed and the needs it is proposing to address. The catchment area should always be appropriate to the nature and scale of the proposal and the settlement it is proposed for. For some developments this may be clear, for example, the catchment area for a school. For a non-major housing development, it would not usually be appropriate for the area of search to extend beyond the specific area of a town or city in which the proposal is located, or beyond an individual village and its immediate neighbouring settlements.
A pragmatic approach needs to be taken where proposals involve comparatively small extensions to existing premises (relative to their existing size), where it may be impractical to accommodate the additional space in an alternative location. Equally, where there are large areas in Flood Zones 2 and 3 (e.g. coastal towns and settlements on major rivers) and development is needed in those areas to sustain the existing community, sites outside them are unlikely to provide reasonable alternatives.
The sequential test should be applied proportionately, focusing on realistic alternatives in areas of lower flood risk that could meet the same development need.
For infrastructure proposals of regional or national importance the area of search may reasonably extend beyond the local planning authority boundary. It may also, in some cases, be relevant to consider whether large scale development could be split across a number of alternative sites at lower risk of flooding, but only where those alternative sites would be capable of accommodating the development in a way which would still serve its intended market(s) as effectively.
Paragraph 28: The following amendments were introduced.
“What is a “reasonably available” site?
‘Reasonably available sites’ are those in a suitable Sites should be considered ‘reasonably available’ for the purposes of the sequential test if their location is suitable for the type of development with proposed, they are able to meet the same development needs and they have a reasonable prospect that the site is available to be of being developed at the point in same time envisaged for as the development proposal.
These In considering whether alternative lower-risk sites (which could include, where relevant, be a series of two or more smaller sites and/or part of a larger site if these) would be capable of accommodating the proposed development. Such lower-risk, such alternative sites do not need to be owned by the applicant to be considered ‘reasonably available’.
The absence of a 5-year land supply is not a relevant consideration for the sequential test for individual applications.”
What do these changes mean?
1) No need for sequential test if you have site-specific FRA
The removal of the sentence in paragraph 23 and the new wording of paragraph 27 make it clear that the sequential test is no longer required if a site-specific FRA has been prepared and it demonstrates that the “proposed layout, design, and mitigation measures” contained within a development are sufficient to " 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 ".
This is a game-changer for developers. It means that, in certain circumstances, robust technical evidence can remove the need for the Sequential Test altogether, streamlining the planning process and reducing procedural burdens. In that sense, this change finally deals with the overly rigid approach previously used and allows developers to properly rely on FRAs.
2) Five-year housing land supply is not relevant for sequential tests
Importantly, the update also clarifies that a lack of five-year housing land supply does not affect whether the Sequential Test should be carried out. Housing delivery can still feature in the overall planning balance, but it’s no longer a gateway to bypassing a sequential test.
3) “Area of search” for non-major housing development is clarified
Paragraph 27a provides much-needed clarity on the “area of search”.
For non-major housing developments that still need to carry out a sequential test (e.g. if the FRA shows that the development does not meet the criteria above), the updated paragraph 27a provides that an appropriate area of search should be limited to "the specific area of a town or city in which the proposal is located, or beyond an individual village and its immediate neighbouring settlements".
Given that this only applies to “non-major” housing developments, then for regionally or nationally significant infrastructure, a wider area of search may be justified. In some cases, consideration should be given to whether development could be split across lower-risk sites, provided the resulting scheme still meets the intended need.
4) “Reasonably available” is better defined
Paragraph 28 defines “reasonably available” more precisely. A site must be suitable for the type of development proposed, capable of meeting the same need, and have a reasonable prospect of coming forward within a similar timeframe. Ownership by the applicant is not a requirement, and two or more smaller sites can together amount to a reasonably available alternative.
Conclusion
The September 2025 update to the PPG marks a significant shift towards a more pragmatic and proportionate approach to flood risk planning.
By allowing site-specific FRAs to remove the need for the Sequential Test in certain cases, clarifying the scope of the “area of search”, and defining “reasonably available” sites, the guidance addresses long-standing ambiguities and procedural inefficiencies.
While the Sequential Test remains a key tool for steering development away from high-risk areas, these changes provide developers and local planning authorities with clearer, more flexible rules that balance flood resilience with practical development needs.
