Installation of Mixer Tap

In this article I will be running through a guide on how to install a mixer tap in your bathroom or kitchen.

Isolate Water Supply

Firstly you need to isolate the water supply to tap in question. This is done depending on your water/heating installation. The quickest and easiest way to do this is to locate the two chrome “isolation valves”- (chrome valves with slot in them for a flat-headed screwdriver) – under your basin/sink. After which, you can put your screwdriver in the vertical slot and turn a quarter turn to the right, so the line is running horizontally. Open up both the taps to drain off the remaining water in the pipes and your good to go.

Boiler Types

If running a combi boiler meaning that both your hot and cold come from the mains then just shutting off your “mains stop cock” will be suffice. Even if not running a combi set up, the mains shut off will stop the feed of cold water to your kitchen tap as by law it has to come from the main line to prevent contamination to drinking water.

If not running a combi then most likely your hot water will be coming from a tank. In this case you need to locate your “cold water tank” which is usually located in your loft or roof space. Once located there will be one to three “feeds” – (copper pipes) coming from the base or sides of the tank. Each one will correspond to either your hot water tank or your bathroom sink, bath or toilet cold feed. It’s a common set up to have a cold storage tank supplying the bathroom appliances and the kitchen supplied by the mains. On each of these feeds there will hopefully be a “gate valve” (copper valve with red wheel on top). Shut all of these off by turning them all the way to the right.

Return to the tap in question and open up both the hot and the cold and after a small amount of water is released both will run dry. Close both the tap heads back off and now you are ready to disconnect the current mixer tap.


I am going to be dealing with replacing a mixer tap that comes with “flexible piping”, basically your new tap should have come with 2 x flexible mono tap connectors that you can screw into the holes in the base of the tap. Also there will be a threaded piece of metal which screws into the other hole in the base of tap. There will usually but not always be a thin black washer or a chrome seating with a washer built into it supplied with the tap. This sits between the bottom of the chrome base and the sink or basin.

You can now look under your sink or basin to see what the piping set up is – again for this article I will be assuming that the current tap to be replaced has come with “flexible piping” connected to two “isolation valves” or two “compression straights” which are now turned off.

Find the nuts connecting the tap connectors to the valves in question and with your adjustable spanner and small rag to catch any water, turn the nuts to the left until fully disconnected and free. Now take your mono tap box spanner of equivalent size and slide up over the hexagonal nut you will see that secures the tap to the sink. Once in position keep turning this to the left until it is also free and the metal and rubber washer that were also holding the tap in place have fallen to the floor.

The tap can now be slowly lifted up, usually the nuts of both flexible pipes together are too wide to come up through the hole. This can be sorted by pulling one up and out before the other or simply unscrewing the flexible hoses from the base before trying to lift the tap out of position.

Install The Mixer Tap

You are all set to install the new mixer tap. Begin by placing the body of the tap on top of your sink/basin hole. With the flexible hoses hanging down through the hole and the threaded piece of metal screwed firmly into the base. Now go back under the sink/basin taking with you the “c” shaped metal and rubber washers, along with the copper/brass hexagonally ended locking nut. Locate the threaded piece of metal sticking down from the base, now the hole you will see in the rubber washer is now pushed up and over that section of threaded metal. Followed by the metal washer also with the hole located over that section of metal. While holding the washers in place with one hand, you want to start screwing on the brass/copper locking nut until it cannot be turned by hand any longer. Taking your box spanner place this over the
hexagonal locking nut and keep turning to the right – (watching as to not move the alignment of the main tap body) – until completely tight and the tap body will not move under pressure.

Just the case of locating the two “isolation valves” or “compression straights” and screwing on the nuts on the end of the two flexible hoses, making sure to get hot and cold the right way round – (usually hot to the left) – Once hand tight use your adjustable to turn another half turn. Take your flat-headed screwdriver and turn back the slot to be sitting vertical again and your new mixer tap is fully installed, ready for use.

Thanks for reading this, good luck installing your new mixer tap, please remember if your unsure or simply don’t have the time we can help with any Edinburgh plumbing and tiling jobs.

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JHDS Plumbing and Tiling accepts no responsibility for damage caused following our guides, if you are ever in doubt please contact a professional before starting a job yourself.