Ultimate Handyman DIY Home how to plumb in a washing machine or dishwasher

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Plumbing in a washing machine, although time consuming is not difficult! With the use of push fit fittings this task is well within the capabilities of a Novice.

Firstly locate the best position for the washing machine or dishwasher, on an outside wall near the sink is Ideal as all pipes will be in close proximity, you normally need a hot and cold supply for a Washing machine and a cold only supply for a dishwasher. A  electrical socket is also needed nearby for the appliance to be connected to the Mains supply.

Dishwashers fill with cold water only and then heat the water after first washing the plates, this is because of EGG Yolk. If the dishwasher heated the water first it would bake the EGG Yolk onto the Plates and cutlery and make it very difficult to remove.

You need to decide which method you are going to use to plumb in your washing machine or dishwasher, please see below-






self cutting tap




push fit








Method 1

The easiest way to plumb in your appliance is to pick up some off the shelf self cutting fittings, these are much more expensive than normal plumbing fittings but if you don't have the correct tools in the first place it could be more economical to to pay for the self cutting type rather than buying all the necessary tools to complete the job as detailed in Method 2. The disadvantages of the self cutting taps and self cutting waste pipe fittings are the cost of the fittings and the need for the appliance to be connected to be very close to the existing pipe work as you are restricted due to the length of the flexible washing machine connector hose. Self cutting taps are only suitable for copper pipe! Advantages are their pure simplicity, speed of fitting and the fact that you do not need to drain down the system. Fitting self cutting taps is very easy, manufactures individual instructions should accompany the fittings when you purchase them. In Most cases it is simply a matter of opening the back plate of the  tap as it is hinged, it then clamps around the pipe, normally there is then a screw to insert and finally the tap body screws into the back plate which cuts an hole in to the pipe, it is then simply a matter of screwing the appliance hose onto the tap tightly! Self cutting waste pipe connectors are similar to fit, they have a body which is clamped to the existing waste pipe, then a screw cutter is inserted into the fitting and turned until a complete hole is cut in the plastic pipe, try and remove the plastic circular piece which you have just cut out as this can cause blockages. After removing the cutter it is simply a matter of screwing the piece into the clamp which accepts the washing machine waste hose, this then needs fastening with a jubilee clip!


Please click here for detailed instructions on how to fit a self cutting tap 


Method 2  

Firstly choose which fittings you are going to use- compression or push fit. Push fit fittings are by far the easiest type of connection, it's simply a matter of cutting the existing pipe and pushing the pipes into the fitting, compression fittings can be difficult to tighten in confined places but are slightly cheaper. The water needs isolating to the two pipes that you are going to cut into, if you are fortunate there will be isolating valves between the main supply side of the system, if not you will have to isolate the water at the main water inlet stopcock and possibly drain down the hot water system, depending on what type of system you have! Another possibility is to use a pipe freezing kit to freeze the pipe whilst you cut into and join the washing machine taps. After isolating the water supply to the two pipes that you are going to enter you must cut into them, there may still be some water left in the pipes so be ready with a  bowl or a towel to soak up the spill. If your pipes are copper the best way to cut them is with a pipe slice, these are excellent for confined places, other than that you will have to use an hacksaw. Plastic pipes are best cut with a dedicated tool which is specifically made for cutting plastic pipe.Now the pipes have been cut you can either fit a T piece and another length of pipe and fix a washing machine tap to this or you can fit a washing machine tap T piece.

washing machine T  

T piece


Now the supply for the appliance has been taken care of, there is now the waste pipe to plumb in.This can vary in difficulty depending on which method you use, typically if the washing machine is close to the sink then a waste pipe trap with spigot trap is ideal. All you have to do is to connect the washing machine waste hose to the spigot which is on the side of the waste trap underneath the sink using a jubilee clip or similar. Ensure that the waste pipe from the appliance is higher than the height of the waste trap otherwise the machine can be emptied by syphonage! It is a good Idea to fix the hose to the kitchen worktop as seen in this diagram by using a screw in hook.sink

  The next method involves buying a off the shelf self cutting waste outlet, this simply clamps around an existing waste outlet pipe and is connected to the waste from the machine. Normally after clamping the body onto the pipe you must insert a cutter which removes a circular piece of the waste pipe. Then another piece is screwed in and the waste from the machine is fastened to this.


washing machine hose




washing machine drain





waste pipe with spigot






If there is no suitable place to connect the waste pipe from the machine you will have to fit a waste pipe and trap. This pipe must connect to the foul water sewer and not the rain water soakaway. The Foul water sewer can easily be identified as this is where the waste from the toilet goes. You will need to make an hole through the wall which is big enough for the waste pipe to fit through, this pipe is normally 40mm.



Please see the section on Fitting a waste pipe



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