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Trade effluent - businesses

Trade effluent is any liquid waste discharged into our sewers from a business or industrial process on a trade premises.


For non-household customers, your retailers should be your first point of contact. For more information on how you choose your retailer, please visit the Open Water website

Understanding trade effluent

Car being washed by an automatic car wash

Trade effluent is any wastewater from a production process or from washing down or cooling activities.

This can include wastewater from carwashes, laundrettes, food and drink production, municipal landfills and more. It doesn't include domestic sewage (toilet, bath or sink waste) or uncontaminated rainwater.

Other wastewater, such as that from hairdressers, swimming pools, offices, hospitals, and restaurants, will need specific guidance for disposal. 

Wastewater treatment centre

We need to control trade effluent to ensure that any matter that may cause harm is not discharged.

Trade effluent is highly variable in strength and volume and may contain substances that are a risk to people, our sewerage network, treatment processes and the environment. Controls are in place to reduce these risks. 

Under Section 111 of the Water Industry Act 1991, it is an offence to discharge any matter likely to cause harm.

Storage containers at waste treatment centre

Trade effluent discharged to our sewers mixes with domestic sewage and is directed to one of our water recycling centres.

First, any large solids are removed. A settlement process then removes heavy particles of solid waste in a sludge, which is further treated and recycled. 

Biological treatment then uses bacteria and microbes to remove organic contaminants from wastewater. Finally, the almost clean water goes through another settlement stage (clarification) to remove any remaining waste particles. The treated final effluent is discharged back into the environment, where it is ready to go through the cycle all over again. You can also buy final effluent for industrial or business purposes. 

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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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