Foul sewage and utilities assessment

You will need to submit a sewage and utilities assessment as part of your planning application which shows how the site will connect to local service infrastructure for water, sewage, and electricity.

This assessment is required for all applications proposing developments in excess of 100 dwellings or 10,000m2 new floor space (or an equivalent combination).

Foul sewage

A foul sewage assessment will need to show:

  • information about the site
  • the site’s suitability to store foul sewage
  • the site’s suitability to transport foul sewage
  • the site’s suitability for treating foul sewage

Information about the existing drainage system must be given when you want to connect to it. Surface water must not be connected to a foul sewer.

When trade waste or foul sewage effluent will not be discharged into a public sewer, the assessment must show:

  • why you can’t connect to an existing system
  • storage methods
  • treatment methods
  • disposal methods

Check to see if building regulations approval is needed for a new or change of drainage system. Scaled plans for new, replaced, or changed foul drainage systems must include:

  • a site location
  • cross sections and elevations
  • specifications

When a connection crosses land that is not owned by an applicant (except public highway), notice may need to be served on the land owner.


A utility assessment must show how a development connects to utility systems, including:

  • confirmation that utility services have been tested and a proposal will not affect any service delivery
  • if utility companies will need substations, telecommunications equipment or similar structures
  • any environmental impacts service routes will have
  • relocation or protection methods to be used when a development affects existing systems.

Further information

For more information about drainage and utilities, and what to include in your assessment, please see the following guidelines: