What Are the Sequential and Exception Tests?

The sequential and exception tests form part of national planning policy designed to guide development toward appropriate locations with the lowest flood risk. These mechanisms enable planners and decision-makers to objectively evaluate sites and applications, steering projects toward safer areas.

The Sequential Test

This assessment compares a proposed development site against other available sites to determine which presents the lowest flood risk. The test is required when development is planned in Flood Zones 2 or 3, and no prior sequential test has been completed for that development type on the site.

According to updated guidance from 20 July 2021, the sequential test aims to “steer new development to areas with the lowest risk of flooding from any source.”

Certain developments are exempt, including minor developments and change-of-use projects (except caravan or mobile home sites). If a sequential test was previously conducted for your development type, you need only provide the local plan allocation reference.

The Exception Test

Applied after the sequential test, this provision allows development to proceed when other options are unavailable or sufficient justification exists. Per NPPF Paragraph 163, the test may apply when “development cannot be located in areas with a lower risk.”

To pass, applicants must demonstrate that the development provides “wider sustainability benefits to the community that outweigh the flood risk” and “will be safe for its lifetime…without increasing flood risk elsewhere.”

Practical Recommendations

We recommend incorporating flood-resilient design, sustainable drainage systems, and risk reduction measures throughout a site’s planned lifetime, positioning the most vulnerable uses in lowest-risk areas.