This guidance is for sewage discharges from domestic and commercial settings.

Domestic settings means housing.

Commercial settings include:

  • hotels,
  • caravan and camping sites,
  • glamping pods
  • cafes, and

Consider the most suitable options – can you connect to the public foul sewer?

Before applying to your environmental regulator, you should consider the most suitable option for your sewage treatment and disposal.

In Scotland, before making an application for a discharge authorisation you should investigate connecting to the public foul sewer. Any proposed development either within or adjacent to the Scottish Water sewer network would be expected to seek a connection unless it can be shown by you that a connection is not possible.

Connection to public sewer not possible – private discharges

If you are not proposing to connect to the public sewer and your site is within or adjacent to this you should provide your environmental regulator justification for this, which should include the following:

  • Correspondence with your water sewerage provider outlining the potential to connect to the public sewer. Find your supplier | Water UK
  • Justification as to why you are not seeking a connection to the public sewer.
  • A detailed cost breakdown comparing a connection to sewer with a private treatment system.
  • A detailed explanation of any technical issues making it infeasible to connect to the public sewer.

For private sewage discharges with a population equivalent of up to 50 it is preferred that the discharge is to land via a closed soakaway. If this is not possible you may be able to discharge to a surface water however you must first show evidence that you have considered a discharge to a closed soakaway.

How to apply

Pre-application discussions

It may be necessary to speak to your environmental regulator, before applying for a sewage discharge Registration. A Registration would be a discharge of up to 3 houses or a maximum population equivalent of 15. This is known as pre-application discussions. 

If your Registration level discharge meets any of the following criteria, pre-application discussions are required.

The discharge is:

  • within 50m of the Scottish Water sewer network, but you do not propose to make a connection
  • within the Loch Leven or Lunan Lochs catchments
  • to a freshwater loch

If none of the above apply, pre-application discussions may not be required, as long as you can show:

  • A ground investigation report (percolation tests) confirms the percolation value (Vp) is between 15 and 100 secs/mm and a closed soakaway is proposed
  • The proposed receiving watercourse is shown on the 1:50,000 OS Landranger Map and a certified package treatment plan is proposed
  • The proposed receiving watercourse is shown on the 1:25,000 OS Explorer Map and a certified package treatment plant is proposed alongside a suitably sized partial soakaway
  • A discharge to estuarial or coastal water is below the Mean Low Water Springs and outwith 1.5km of a Bathing or Shellfish water

To register a domestic sewage discharge complete this form: SEPA: Register a sewage discharge in Scotland  

For a commercial sewage discharge complete this form: SEPA: Register a new commercial sewage discharge

If you are applying for either a Licence level discharge the above criteria do not apply and you are encouraged to contact the Water Permitting team at SEPA for pre-application discussions.

Who to contact for pre-application discussions

If you need to have pre-application discussions you can contact your environmental regulator to do this. You must provide them with the information outlined earlier in this guide. To contact the Water Permitting team at SEPA you can send an email enquiry to

What information should you supply?

For pre-application discussions or when applying for a private discharge, you should supply the environmental regulator with the following supporting information:

  • National Grid Reference (NGR)
  • Site drainage plan including discharge location
  • General site plan showing plot and surrounding area
  • Evidence and justification showing connection to sewer not feasible
  • Ground investigation report or alternative evidence outlining why the ground is unsuitable for a closed soakaway
  • Population equivalent calculation (for commercial discharges)
  • Details of proposed treatment plant including mean effluent standards for BOD and ammonia (must be shown as mg/L)

There are a number of resources available to help you in determining the most appropriate treatment for your development and for gathering the above information, see further information section below.

Further information

You should also refer to the relevant guidance documents before approaching your environmental regulator for advice. These will help you understand the requirements for your development. The following documents will assist you:

Building standards technical handbook 2020: domestic