5 Live Updates arrow
Account Login

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 liquid waste (effluent) discharged into our sewers from a business or industrial process on a trade premises.

This includes any wastewater derived from a production process or from washing down or cooling activities, including wastes from public-funded activities such as municipal landfills. (can remove if too much info)

This can also be described as anything other than domestic sewage (toilet, bath or sink waste) or uncontaminated surface water and roof drainage (rainwater).

Section 141 of the Water Industry Act 1991 defines trade effluent as: 'any liquid, either with or without particles of matter in suspension in the liquid, which is wholly or partly produced in the course of any trade or industry carried on at a trade premises.'

Trade effluent includes wastewater from, but not limited to:

  •            Commercial car washes
  •       Laundries/launderettes
  •       Food and drink production
  •       Chemical manufacturers
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

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. In some cases, further treatment is required to meet stricter limits, where for example, we discharge into nutrient-sensitive watercourses or bathing waters. 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. 

Need more support?

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

Cookies required

It looks like some of your cookies are disabled. If you want to use this feature, please enable functional cookies and refresh the page.