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Trade effluent - retailers

Trade effluent is any liquid waste (effluent) discharged into our sewers from a business or industrial process.

A Southern Water engineer works outdoors at the Peacehaven Wastewater Treatment Works

What is trade effluent?

Trade effluent includes wastewater from production processes, or from washing down or cooling activities. This is best described as anything other than domestic sewage (toilet, bath or sink waste) or uncontaminated surface water and roof drainage (rainwater).

Frequently asked questions

Here you'll find answers to some commonly asked questions about trade effluent for retailers.

You'll need to submit an application on the Bilateral Hub as a G2A or G2B process. The application forms can be found on the MOSL website.

The completed form must be signed by the authorised signatory of the applying company and attached to the service request.

Please refer to our current Wholesale statement of principles and charges.

Trade effluent is covered in sections:

  • Section 2, Part 3 for primary charges
  • Section 4, Part 12 for non-primary charges

Please contact us if you have any further queries.

Recovery of incurred costs


  • The recovery of extraordinary costs incurred by Southern Water due to an event caused by your customer. This includes but isn't limited to damage to our assets or increased operational costs

  • The recovery of costs incurred by Southern Water through pre-emptive measures. We'll undertake these to minimise the impact on our assets in anticipation of a breach (or breaches) of your trade effluent consent
Formal sampling charge

The recovery of costs incurred by Southern Water in respect of formal sampling undertaken in accordance with our policies and procedures, due to failing to comply with your customer's consent.




Recovery of incurred costs

Determined on an individual incident basis

Formal sampling charge (7am - 6pm)

£255.00 per sample

Formal sampling charge (6pm - 7am)

£480.00 per sample


As per the G4 process, when all sample analysis is completed and verified the results are sent to the trade effluent customer by email. The results are also made available to their retailer through our retailer portal.

Retailers will be sent an email notifying them when results are added.

You can find the results under Section 5: Trade Effluent - G Forms – TE monitoring and search by SPID.

Consent conditions may require flow measuring equipment such as a private meter to be provided, maintained and records kept. The cost of installing and maintaining such equipment will be the responsibility of the discharger.

Assessment of flow by other means such as private water meters or process meters may also be used by trade effluent dischargers. This can aid with calculation, accuracy of billing, and improved monitoring.

Any flow measuring equipment and installation used for trade effluent billing should be to MCERTS standard.

Yes. You'll need to register private meters used to calculate trade effluent bills in the market.

Please notify us that your customer has installed, exchanged, or has an issue with a private meter with a G01 which will be submitted on the Bilateral Hub. Please complete this form and attach to the G01 enquiry.  Please refer to the Market Operational Codes (Schedule 1 Part 3) under B12, B13 and B14 to view the processes that you may need to follow.

A view of Budds Farm Southern Water site

We're here to help if you have any other questions.

Please complete the G1 process on the Bilateral Hub (on the MOSL website) for queries relating to:

  • A site visit or communication we've had with your customer
  • An enquiry from the customer
  • The details or processing of a trade effluent consent
  • Quality and analytical or monitoring information
  • Central Market Operating System (CMOS) data / trade effluent account set up
  • Consent compliance or enforcement carried out by Southern Water

Need more support?

We're here to help with any other queries you may have. Please fill out this form in as much detail as possible to help us answer your query.

Repaired a leak

This can be found in the top right corner of your bill and is 8 or 10 digits long.

This is the reference on the back of the leaflet that one of our members of staff left with you

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