Tom Melhuish 5 min read

Understanding sewage

Understanding sewage and your wastewater charges are essential as a business. You need to make sure you have the correct consent for any commercial processes that add contaminants to the sewerage system.

This guide will look at what sewage is and the relevant charges your business will incur.

What is sewage?

Simply put, sewage is wastewater created by households, at the workplace and in factories. It’s caused by the general use of facilities within your business and trade effluent created by commercial practices.

The wastewater (Sewage) is then deposited into the sewerage system and treated within the treatment facilities.

What is the sewerage system?

The sewerage system is the pipe network that transfers your wastewater to a treatment facility to either be disposed of or cleaned and reused.

After treatment, wastewater flows back into natural reservoirs with the by-product of the treatment disposed of in landfills and/or by incineration.

There are three key elements to the wastewater sewerage system, these are:

  • Combined sewers: Sewers that are old single pipe systems. These carry both surface drainage water and wastewater for treatment at the treatment facility.
  • Foul sewers: Sewers that take wastewater from business premises to the treatment facilities.
  • Surface water sewers: The surface water sewers take the natural rainwater and carry it to deposit back into rivers and streams.

What’s the difference between wastewater and surface water?

This is a question that’s asked often. The difference between these two are:

  • Wastewater is where human processes like using the toilet or washing your hands produce contaminated water.
  • Surface water falls on the roads, pavement, and buildings that then fall into the public sewers.

Another type of wastewater to be aware of is Trade Effluent. Trade Effluent is where a commercial process has contaminated water.

What is trade effluent?

Trade effluent is a form of wastewater contaminated by commercial processes that flows into public sewers. The commercial processes can be anything from production on your premises to processing food.

The term trade effluent includes wastewater contaminated by chemicals and oils. Trade Effluent rules apply to businesses of any size.

Trade effluent charges will be presented separately on your water invoices using the Mogden formula.

When do I need consent for trade effluent?

There are a couple of situations in which your business will need consent for trade effluent. Consent is required when:

  • Surface water run-off is contaminated by your surfaces and enters the sewer, you must receive consent for trade effluent.
  • Your business produces trade effluent into the public sewers.
  • And when the contaminated liquid is being disposed of in sinks, toilets, or other drains within your premises.

You will also need to get consent if you’re there only for the short term. For example, if there are building works or you are just on the premises for a matter of months before moving. Consent for trade effluent is a must.

Examples of liquid waste that do not count as trade effluent are:

  • Domestic sewage – including wastewater from kitchen sinks, showers and toilets.
  • Clean, uncontaminated surface water – ie clean rainwater which has not been contaminated when running over your site.
  • The disposal of beer down a domestic sink is also not classed as trade effluent.

Where can I get consent for trade effluent?

You can get consent for trade effluent from your local water companies in England, so you should approach your current supplier if you currently don’t have consent.
If you’re a business located in Scotland, consent for trade effluent can be acquired from Scottish Water.

How are wastewater and sewerage charges calculated?

Wastewater and sewerage charges are calculated by several factors, these are:

  • Highways drainage charges
  • Surface water charges
  • Trade effluent charges
  • Foul sewage charges

Depending on the volume of the different wastewater criteria will determine the amount you pay on these. Your water supplier and how their rates for wastewater and sewage are calculated will also be a factor.

For more information on how the above charges are calculated, please click on our Understanding Business Water Charges Guide.

How do I reduce my wastewater (Sewage) bill?

There are many ways you can reduce the cost of your wastewater bills. Firstly, you should look at your current charges and look at other providers to see if you can save money.

You should also ensure that your business is water efficient and doesn’t leak or damage pipes. As there’s potential, you’re being charged due to burst or damaged pipes, something that’s not always as apparent.

To check out the latest water and wastewater charges, use our business water comparison service, and one of our experts will be in touch with you.