Sustainable Drainage Systems Design Guidance

This advice sets out the requirements that the LLFA has for drainage strategies and surface water management provisions associated with applications for development.

Implementing the Discharge Hierarchy

When deciding on which SuDS to use, the discharge hierarchy should be applied. It is a hierarchy of connection prioritising what should be done with the surface water once it has been collected on site. 

The Hierarchy:

  1. Collection for reuse
  2. Infiltration
  3. Watercourse or other surface water body
  4. Surface water sewer, highway drain or other drainage system
  5. Combined sewer

Where a developer proposes to connect surface water to the existing sewer system, they should provide evidence showing how the surface water hierarchy has been applied to the site and why connection to the sewer is the most practical solution.