Environmental guidance for your business in Northern Ireland & Scotland

Trade effluent consents and agreements

Trade effluent consents

You must get a trade effluent consent or enter into a trade effluent agreement with your water and sewerage company before you discharge trade effluent into a public foul sewer. It's important you do this to avoid causing serious damage to the sewage system and creating a risk of danger to public health.

Trade effluent is any liquid waste resulting from non-domestic or industrial activity. It includes:

  • wastewater contaminated with oils, chemicals and solvents
  • liquid process wastes
  • detergents
  • condensate water from compressed air installation
  • cooling and wash water
  • biodegradable liquids
  • contaminated mine or quarry water.

If your effluent is hazardous, you must dispose of it as hazardous/special waste.

Hazardous/special waste

You must have a trade effluent consent or agreement if you:

  • discharge trade effluent into a public foul sewer
  • discharge any surface water run-off from oil-contaminated hard surfaces or wash substances such as oils, chemicals, food, inks or powders into a public foul sewer
  • use a sink, basin, toilet or gully for disposing of any liquid wastes or discharge wash waters into a public foul sewer, apart from domestic sewage.

If you're already discharging trade effluent to the public foul sewer without permission, you should stop immediately and contact your water and sewerage company.

You must arrange for a new trade effluent consent or agreement if:

  • the volume or composition of your discharge changes
  • you are no longer able to comply with the conditions of your consent or agreement
  • you stop the discharge for more than 2 years and then want to start it again.

You may also need prior authorisation from either the Northern Ireland Environment Agency (NIEA) or Scottish Environment Protection Agency (SEPA) for effluents containing dangerous substances, or if you have a pollution prevention and control permit. You should check with the NIEA or SEPA, or your water and sewerage company if you are unsure whether you need authorisation.

Trade effluent – managing liquid wastes

Further information

Water UK: Water and sewerage operators

Scotland on tap: Water suppliers in Scotland

In this Guideline

Types of environmental licence

Pollution prevention and control permits and waste management licences

Authorisations and consents for discharges

Trade effluent consents and agreements

Water abstraction and impoundment authorisations

Waste carrier, broker and dealer registration

Hazardous/special waste notifications

Radioactive substances authorisations

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NIEA - Apply online

SEPA - Application forms