On 17th September 2025, the government finally updated their planning practice guidance on flood risk, following changes to the National Planning Policy Framework (NPPF) last December. This now includes a more proportionate approach to how the sequential test for surface water flood risk is to be applied to planning applications. Previously, even if a flood risk assessment proved that a development would be safe from surface water flooding, the sequential test still needed to be applied, requiring an assessment of reasonably available alternative sites. However, updated planning practice guidance now states the following:
“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.”
This shift towards a more pragmatic approach is welcomed, but is still likely to cause disputes within the industry. One of the main inconsistencies is that the proportionate approach specifically applies to surface water flooding, rather than fluvial or tidal flooding. A challenge in the near future is therefore highly likely.
The changes also include more detailed guidance on how to define the area of search when applying the sequential test to planning applications, and what constitutes a ‘reasonably available alternative’ site. Overall, these changes are positive, and may present an opportunity to reconsider development opportunities that have previously been discounted for flood risk reasons. Should you wish to discuss such opportunities, or have a site that has historically failed to pass the sequential test, then please contact our Planning Team for advice.
Samuel Allcock