Misconnected appliances

Save-the-earth I have an important message about misconnected appliances (washing machines and dishwashers) contributing to damaging the environment and how any one of us could be unwittingly part of the problem. This is part 2 where I describe my own experience of finding out I was “misconnected”, which will help you understand the issue more too. (Part 1 | Part 3)

My personal experience

Sadly I myself have been a victim of this when I moved into a new house and the previous occupier had installed a washing machine in the garage.

Garage-plumbing This is the fall pipe from the guttering on my garage roof where it runs into the storm drain. This harmless water joins the surface water drainage system under our roads and it runs untreated, directly into local rivers and streams.

Unfortunately, you can also see a small pipe to the left, which is the waste water pipe that the washing machine pumps into. This washing machine is misconnected! The dirty waste water full of chemicals and bleaching agents is being pumped directly into a local river instead of going to a water treatment plant and this needed correcting.

Out-buildings and garages

Out-buildings and garages aren’t normally connected to the sewerage system. This means most people installing a washing machine are likely to misconnect the waste water pipe to the storm drain instead – which is illegal.

How to make sure you have no misconnections to the sewerage system

main-fall-pipe-system This picture shows a 4 inch main waste water pipe which is typically found at some point on a house round the back. All of the waste water pipes from the bathroom, kitchen, and appliances such as washing machines and dishwashers should be connected to this pipe, or pump out into a grate next to it.

All water from these sources is potentially “dirty”, and needs to go to water treatment plants so it can be cleansed before being allowed into rivers.

  • Look at the large 4 inch stack pipe on the outside of your home where the toilet is connected
  • All your waste water plumbing should run into this pipe (or a connected grate next to it)
  • No guttering fall pipe should be connected to it

If roof guttering is connected to this large waste pipe it can contribute to flooding during heavy rain as the sewerage system cannot cope with all the extra water. Rainwater should run into a separate system.

How to make sure you have no misconnections to the surface water drainage system

All-connections This photo shows everything connected correctly. You can see that the lone pipe on the side of the house (from the bathroom) runs around the corner and connects to the main 4 inch pipe sewarage pipe. This is correct.

The lone pipe actually passes underneath the fall pipe for the guttering. Someone could easily have taken the easy option and connected the lone pipe to the fall pipe at the corner. This would have resulted in soap, dirty water, shampoo and other undesirable liquids draining into the local river or stream.

  • Look at the guttering on your house and other buildings. Check the connected fall pipes
  • No other pipes should connect to this system. Only rainwater should run into it
  • At the bottom of the guttering fall pipe there may be an open grate. Only rainwater from the roof should run into this grate or be connected to this fall pipe. No plumbing from an appliance or sink should be connected in such a way that it runs into this pipe or grate


There are two types of water which flow from our houses and out-buildings. Rain water which falls on roofs, and water we have used and no longer need from our toilets, sinks, washing machines and dishwashers. There are two separate systems for dealing with these different types of water – and if connections are made the wrong way round it can cause environmental problems and is actually illegal.

More on misconnections

Learn-more Don’t forget to read the information on the right column (or below if reading on a mobile device) which contains more information on this topic.

In these tough times, wasting money is not an option. Do some research first. Which? have a genuine no-strings trial offer. For only £1 you get the following benefits -

  • 1 month access to all the information & reviews on Which? Online
  • Access to Which? Local - a database of Which? members recommended tradesmen and reviews
  • A copy of the Which? magazine delivered to your door
  • Access to Which? Legal Services
  • Get your Which? offer | What's the catch?



  1. avatarMatt says

    This kind of depends on where you live, as many big cities have combined sewer systems, where storm drains flow down into the larger sewer systems deep beneath the ground and, most of the time, get swept off to be treated at the various plants. Only in times of extreme wet weather do these combined systems overflow into rivers, and for this kind of plumbing to therefore be an environmental hazard you not only have to have extreme wet weather, but also have to be running your appliance at the same time.

  2. avatar says

    Hello Matt. This is more of a problem because we are getting more and more extreme wet weather but the storm drains overflowing due to being unable to cope is the smaller issue. The biggest environmental hazard is more to do with appliances pumping detergent et cetera into the rivers.

Comments Moderated:

Comments must be on topic or they won't be published. Please don't ask questions that are answered in the article itself.

Leave a Reply

Your email address will not be published. Required fields are marked *