Sequential Tests for Flooding

What is a Sequential Test?

A Sequential Test is a requirement under national planning policy when your proposed development is at risk of flooding. It ensures that any development cannot reasonably be placed on a site with lower flood risk. That means identifying and evaluating alternative sites or locations and justifying why your chosen site is the most appropriate.

When You'll Need a Sequential Test?

You’ll generally need to carry out a sequential test if your site falls into:

• Flood Zones 2 or 3

• Areas prone to surface water, groundwater, or other flood risks

There are exceptions. In some cases, smaller developments (such as householder extensions or minor non-residential works under specified size thresholds), or change of use applications, may not require a full sequential test. Where sites are already allocated in the local plan and previously assessed, the test may have already been satisfied.

Recent changes to planning guidance also state that a Sequential Test should not be required where a site is subject to surface water flooding, and the risks can be effectively mitigated.

Defining “Reasonably Available” Alternative Sites

A key part of the sequential test is proving there are no reasonably available alternative sites. These are sites that:

• Are in a suitable location for your proposed development

• Can be delivered in a comparable timeframe

• Meet your size, access, and infrastructure requirements

Often this involves reviewing multiple smaller sites, or parts of larger ones, to ensure a thorough search and robust justification.

Exception Test: What Happens Next

If your development passes the sequential test but remains in high-risk flood zones, you may also need to satisfy the Exception Test. This requires you to show that:

• The benefits of your development outweigh flood risks

• User safety over the lifetime of the development is assured

• There is no increased flood risk elsewhere

Why Choose Cedar Planning for Your Sequential Test

We combine technical expertise with a client-focused process:

• Local authority engagement: we agree search parameters with your council to align with policy expectations.

• Detailed alternative site analysis: we conduct robust comparative studies to support your case.

• Compliance: our sequential tests meet all relevant planning policy and flood risk guidance.

• Clear, honest assessments: if chances of approval are low, we’ll tell you.

Our Process

• Initial consultation & site review – understand your site’s risk profile.

• Agree search area and criteria with you and the council.

• Locate and assess alternative sites.

• Produce a full Sequential Test report, with maps, risk analysis, and recommendations.

• Support through submission and discussions with planning authorities.

Benefits of Using a Professional Sequential Test Service

• Maximises your chance of planning approval

• Saves time & reduces risk of refusals or appeals

• Ensures compliance with both national and local policy

• Offers peace of mind with well-documented evidence

Get a Free Quote for a Sequential Test

Let’s assess whether a sequential test is required for your development, and how strong your site’s case is. Fill out the form below for a no-obligation fixed-fee quote, or contact us directly to discuss your situation.