After months of anticipation, the government has published its long-awaited update to national planning guidance on flood risk. The new Planning Practice Guidance (PPG) introduces notable adjustments to how the flood risk sequential test is applied, a move that, according to many in the sector, could simplify development in higher-risk areas while narrowing local authorities’ ability to resist it.
For nearly two decades, the sequential test has been a cornerstone of flood risk management in planning. Its purpose is simple in theory: to direct new development towards areas with the lowest probability of flooding. In practice, however, the test has often been criticised for creating delays, confusion, and inconsistencies between local planning authorities (LPAs).
Shifting policy context
In late 2023, the government revised the National Planning Policy Framework (NPPF), signalling that changes to the PPG would follow. The updated framework clarified that a sequential test is not needed where a site-specific flood risk assessment (FRA) demonstrates that the proposed development, including access roads or land raising, is located outside areas of flood risk. It also broadened the definition of “flooding” to include surface water risk, not just fluvial or tidal flooding.
While these clarifications were meant to streamline the process, they had the opposite effect for many developers, who were unsure how to interpret them. A number of planning applications were paused while the sector waited for formal guidance.
That guidance has now arrived. The updated PPG provides additional clarity on when the sequential test can be avoided and how developers should identify “reasonably available” alternative sites.
What’s new in the guidance
The most significant change appears in paragraph 27, which states that the sequential test may not be required if a site-specific FRA shows “clearly” that the proposed layout, design, and mitigation measures will protect future occupants from both current and future surface water flooding for the lifetime of the development, without increasing flood risk elsewhere.
This subtle but important shift opens the door for developers to argue that engineering-led mitigation, such as drainage schemes or raised design, can make a site acceptable even in areas previously ruled out under the sequential test.
The new guidance also expands on the “area of search” for alternative sites, introducing the idea that this should be proportionate to the scale of development. For smaller residential schemes, the area would typically be confined to the settlement and its immediate surroundings, while strategic infrastructure projects may justify a wider, even cross-boundary, search.
Additionally, the PPG clarifies what counts as a “reasonably available” site. Such sites must not only be suitable and deliverable but must also meet the same development needs as the proposed site, and crucially, they do not need to be in the applicant’s ownership.
Why these changes matter
Earlier this year, the Environment Agency updated its flood map for planning, significantly expanding the number of areas now classified as at risk from surface water flooding. This, said Paul Smith, Managing Director of the Strategic Land Group, turned the sequential test into a “real issue” for developers. “The government produced the new guidance to remove a barrier to development effectively overnight,” he explained.
Others believe the revisions reflect political as well as practical motives. Claire Petricca-Riding, a partner at law firm Irwin Mitchell, said the changes are the result of “hard lobbying” from the development sector and a reflection of the government’s push to “unlock sites stalled by the sequential test” as part of its wider growth agenda.
Practical impact on planning decisions
While the revisions apply to both plan-making and decision-making, their greatest impact will likely be felt in individual planning applications. Chris Lyons, Head of UK Planning at SLR Consulting, noted that councils already use strategic flood risk assessments at the plan-making stage, meaning they can often avoid the sequential test. For development management teams, however, paragraph 27 offers a practical route to demonstrate that mitigation measures can render a site acceptable.
As Smith put it, “Previously, if any part of a site was at risk of surface water flooding, planners had to carry out the sequential test across sometimes vast areas or conduct hydro-modelling to prove the EA’s maps were wrong, which takes months and costs a fortune.”
That burden may now ease. Lord Charles Banner KC, barrister at Keating Chambers, called the new guidance “the most significant part of the PPG,” adding that many projects “were getting tied up in difficulties over the sequential test due to surface water and that’s now, on the face of it, been resolved, provided that those developments can be shown to be safe and not increase flood risk elsewhere.”
Still, not everyone is convinced. Andrew Coleman, Senior Lecturer in Town Planning at the University of Brighton, warned that councils in high-pressure areas such as the South East “may not welcome these changes” because they will make it harder to resist development. Hugh Ellis, Director of Policy at the Town and Country Planning Association, echoed that concern, arguing that the new guidance “stops [local authorities] having the power and the process to direct development towards intrinsically climate-resilient places.”
Balancing clarity and risk
Despite those concerns, practitioners have largely welcomed the practical clarity the guidance brings. Max Kidd-Rossiter, Associate Director at Lichfields, described it as a “common sense” approach, although he noted that further explanation on what constitutes a “realistic alternative” site would still be useful.
The changes could also streamline workloads for overstretched planning teams. As Nicky Linihan, housing spokesperson for the Planning Officers Society, pointed out, the new definitions “remove the need [for councils] to debate these definitions when dealing with individual planning applications” and provide “more predictable outcomes” for developers.
For some, the guidance is already shaping live applications. Kidd-Rossiter cited one client that reconfigured its proposed housing layout to place development within medium, and high-risk zones, confident that its on-site drainage solutions will satisfy the test’s safety requirements.
Yet, as Banner cautioned, changes to guidance can have “more unforeseen consequences” than updates to the NPPF, which undergoes wider consultation and legal scrutiny. The full implications of the PPG, he said, “will therefore need to be fleshed out through test cases.”
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