What the NPPF changes mean for the Sequential Test

What is the Sequential Test?

The Sequential Test is a planning mechanism outlined in the National Planning Policy Framework (NPPF) that aims to ensure new development is directed to areas with the lowest probability of flooding. It applies primarily to areas at risk of flooding from rivers or the sea, but its scope has recently increased to encompass surface water flooding.

For proposals located within any form of flooding risk, applicants must demonstrate through a Sequential Test that there are no reasonably available sites at lower flood risk that could accommodate the development. If such alternatives exist, planning permission is unlikely to be granted. If none exist and the test is passed, the Exception Test may then apply, requiring further justification based on sustainability benefits and safe design.

NPPF December 2024 updates

Historically, the Sequential Test has been a relatively rare planning process for developers, agents and local planning authorities to grapple with. However, the December 2024 update to the NPPF significantly broadened the scope of the Sequential Test in relation to flood risk, making it a more frequent requirement in planning applications.

Most notably, paragraph 175 of the revised NPPF now confirms that the Sequential Test must be applied to development proposals in areas known to be at risk from any form of flooding, not just fluvial or tidal flooding. This includes surface water, and so greatly expands the range of sites where the test is triggered.

The update also clarifies that the Sequential Test applies to all types of development where any part of the proposal, such as built structures, land raising, access/egress routes, or sensitive uses, falls within a flood-risk area. Previously, the test was generally associated with major developments in Flood Zones 2 and 3. Now, even relatively minor developments in areas susceptible to localised surface water flooding can fall within its scope.

Sequential Tests can only be avoided where a site-specific Flood Risk Assessment (FRA) clearly demonstrates that no part of the proposed development, including any potentially vulnerable element or access, is located on land at risk of flooding, either now or in the future. Importantly, the NPPF now makes clear that the presence of mitigation measures does not remove the need for a Sequential Test if any part of the development is located in a flood-risk area.

A sharp rise in the number of Sequential Tests

The result is that there has been a sharp increase in the number of planning applications which require a Sequential Test to be carried out. By including all forms of flooding and requiring complete flood avoidance – not just risk mitigation – it has become a more prominent and frequent feature of the development management process.

Case study

Following the December 2024 update to the NPPF, Savills has developed a refined GIS mapping approach to help clients navigate these expanded requirements. This allows us to undertake robust Sequential Test assessments by enabling a clear spatial analysis of flood-risk zones and alternative sites, clearly demonstrating the relative flood risk of potential development sites and so strengthening the robustness of the reports.

Savills prepared the Flood Risk Sequential Test in support of Churchill Living’s allowed appeal for a 177-unit multigenerational community scheme in Christchurch, Dorset, which fell within Flood Zone 2 and future Flood Zone 3b.

When allowing the appeal, the Inspector stated that the Sequential Test was met and that the report was ‘thorough and convincing’.

In Summary

The Sequential Test has become a much more prominent consideration in the planning process following the December 2024 updates to the NPPF. With a broader scope and stricter requirements, it now captures a wider range of developments and flood risks making early and robust assessments essential.

Case law from 2025 reinforces the need for a balanced, evidence-led approach that recognises both policy obligations and real-world risks. It is believed that the Planning Practice Guidance is due to be updated this summer to provide further clarity on the triggers for the Sequential Test, as well as its application.

Further information

Contact Becky Rayner or Peter Warren