How to Fix a Leaking Mixer Tap

How to guides

A dripping tap can be a considerable nuisance. From the repetitive dripping that keeps you awake at night to the increased water bill, there’s no joy in a leaky tap. Ignoring it will not make the problem go away, so it’s best to fix that tap as soon as it starts leaking. The good news is that in most cases fixing a leaky tap is a simple DIY job.

Why is my tap dripping?

Usually, when a tap begins to leak it is because one of the parts that make the mechanism watertight when it’s turned off has worn out. The most common causes of a leaky tap are a worn-out washer or a worn-out O ring.

What is a Tap Washer?

A tap washer is a type of gasket or seal that regulates the flow of water and, when the tap is turned off, creates a seal that stops water from flowing. With time, and depending on the use of the tap, the washer can wear out  or become misshapen, failing to properly seal the valve and allowing small amounts of water into the spout, causing your tap to leak.  This mechanism will be different depending on the type of tap you own.

How can I tell which type of washer my tap has?

Older taps use rubber washers, while newer taps are more likely to use a ceramic disc or valve. One way to tell which kind of washer your tap uses is by checking how far the handles rotate. Traditional taps often can be rotated at a full turn or more to let the water flow. Taps with ceramic washers are known as ‘quarter turns’, as they only need to be rotated a quarter of a turn to let the water flow. Monobloc or leaver taps are also commonly equipped with ceramic washers. Below, we’ll take a look at how to fix both of these types of tap.

How to change a rubber washer

Rubber washers are common in older, more traditional taps. They are round, doughnut-shaped gaskets made out of rubber and other malleable materials that are placed at the bottom of the stem. When the tap is turned to the ‘off’ position, the washer presses down on the valve seat and creates a watertight seal, stopping the water from flowing through the tap spout. To change the washer you will need to:

1. Turn Off the water supply.

Before you do anything, turn off the water supply either by turning off the general supply valve or by turning off the isolation valve under your sink.

2. Turn on the tap 

Turn the tap on and off to release any water that may still be at the top of the pipe.

3. Find and remove the screw that holds the tap together. 

This will usually be hidden under a decorative cap on the top of the tap handle that you can remove with the tip of a flat screwdriver. 

4. Remove the faucet handle

Some will come right off, while others may need to be unscrewed. This should expose the stem of the tap.

5. Loosen the stem nut

With an adjustable spanner, loosen the large hexagonal nut that holds the stem together, while holding the body of the tap in place. The stem should pop off, but some may need to be twisted to remove. 

6. Check the washer for signs of wear and damage

Once you have removed the stem, you should be able to see the washer at the bottom of the stem. Check to see if it is worn out, this is most likely the cause of the leak. 

7. Replace the washer. 

If you have a traditional tap with two separate handles, it is worth replacing both washers at the same time.

8. Put all the parts back together.

Tip: Organise the different parts of the tap as you take them apart, so you can remember how to put everything back together.

Tip: Always put the plug in the sink before you begin taking the tap apart. This way if the small screws at the top of the tap handle slip in between your fingers they won’t be lost forever down the drain.

How to change a Ceramic Washer

On newer taps and monobloc (mixer) taps the rubber washer is replaced by a ceramic washer, composed of two tightly fitting ceramic discs. One of the discs is fixed in place, while the other one rotates as you rotate the tap handle. When the tap is turned on the discs align to let water through. Although ceramic cartridges are more hard-wearing than rubber washers, they can fail if the ceramic scratches, breaks, or if dirt accumulates between the discs.

1. Turn off the water supply

Before you do anything, turn off the water supply either by turning off the general supply valve or by turning off the isolation valve under your sink.

2. Turn on the tap 

To release any water that may still be at the top of the pipe.

3. Find and remove the screw that holds the tap together 

On monobloc lever taps, this is often found under the hot and cold indicator button. Remember to plug the sink, so the screw cannot go down the drain if it slips your fingers.

4. Remove the faucet handle

Some will come right off, while others may need to be unscrewed. This should expose the stem of the tap.

5. Loosen the stem nut

With an adjustable spanner, loosen the large hexagonal nut that holds the stem together, while holding the body of the tap in place. The stem should pop off, but some may need to be twisted to remove. 

6. Remove the hot and cold water cartridges

Mixer taps have separate cartridges for hot and cold water supply, make sure to identify which is which. 

7. Identify and replace the defective cartridge

If you are unsure of what type of cartridge or ceramic washer you need, take the old cartridge with you to the store to find the exact one.

8. Put everything back together

It’s a good idea to pay attention to how the parts are assembled together when you are disassembling, and organise them in the order in which you take them apart, so you can put everything back together with ease.

What is the O ring?

The O ring is a seal similar to a washer, located at the base of the spout or tap body. If your tap is still leaking after replacing the washers, or if it’s leaking at the joining part of the body rather than through the spout, the O ring may be at fault. 

How to replace the O ring

  1. Release the grub screw located at the back of the tap 

  2. Carefully remove the spout

  3. Use a flat head screwdriver to lift and remove the O ring at the base of the spout

  4. Replace the O ring

  5. Put the tap back together

Contact a Professional

If you’re unsure about any of the solutions listed above, or have tried them out without success, we recommend that you contact a professional that can help you discern the exact problem and swiftly fix it. Home Assist Repairs and Servicing deploys qualified plumbers across the North of England, to attend to plumbing repairs and installations. Contact us today by calling 0191 406 0888 or requesting a call back here.

Scott Flannigan

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