A leaking kitchen tap, even a slight one, can waste dozens of litres of water every day. The cause is often a worn or badly positioned washer. Fortunately, you can replace it yourself with a few basic tools. Here is a practical guide to fixing it quickly and extending the life of your kitchen sink tap. The same steps apply to a kitchen mixer tap, whose cartridge is covered below.
Why does a tap washer wear out?
Rubber washers seal the joints between the different parts of the tap. With use, they compress, crack or become misshapen. This often causes leaks at the spout, the base or the handle. Limescale, excessive pressure or very hard water also speed up wear.
Taps with a pull-out spray can have several washers, particularly on the cartridge, the hose or the fixing base. Replacement is slightly more technical but still within anyone's reach.
What tools do you need to replace a washer?
Before you start, make sure you have:
- A set of compatible washers (often supplied as a kit)
- An open-ended spanner or grips
- A flat or Phillips screwdriver
- PTFE tape (optional, to seal threads)
- A bucket or bowl to catch the remaining water
Step 1: Turn off the water supply
Close the isolation valves under the sink by turning the handles clockwise. If you do not have a local valve, turn off the main supply to the house. Then open the tap to release the pressure and drain the system.
Step 2: Find the leak
It is important to pinpoint exactly where the leak comes from:
- Leak at the spout: the head washer or the cartridge is often to blame
- Leak at the base: check the fixing washer or the connectors
- Leak on the hose: an O-ring may be worn
Depending on the model, you will need to take off either the handle, the spout or the connectors under the sink.
Step 3: Take the tap apart
Start by removing the handle, usually held by a screw hidden under a plastic cap. Then remove the cartridge or head mechanism with a spanner. Note the direction of fitting before taking the parts out. If you need to remove the whole tap, follow our method for removing the kitchen sink tap.
If the tap has a pull-out spray, unscrew the hose from underneath and inspect the washer at the junction between the spout and the hose.
Step 4: Replace the worn washer
Remove the damaged washer by hand or with pliers. Clean its seat carefully with a cloth or an old toothbrush. Fit the new washer without forcing it, making sure it sits flat in its housing. If you are refitting a thread, you can add a little PTFE tape to improve the seal.
Step 5: Reassemble and test
Put all the parts back in the reverse order of removal. Slowly open the isolation valves, then the tap, to check there is no more leaking. Watch the spout, the connectors and the base carefully for a minute or two.
If the leak persists, another washer may be damaged or badly positioned. Repeat the inspection if needed. If the water is coming from somewhere other than the washer, our guide to finding where a tap leak comes from goes through the spout, the neck, the base and the connectors under the sink.
What if the problem is the cartridge?
On modern mixer taps, the mixing cartridge can be the cause of leaks. In that case it has to be replaced completely. The procedure is similar to replacing a washer, but you need to buy a cartridge that is compatible with your tap. Universal cartridges are not always suitable.
If your tap is old, heavily scaled or damaged, consider replacing it with a new model. Discover our full selection of kitchen sink taps or our models with built-in pull-out spray for more everyday comfort. For fitting the new one, see how to change a kitchen tap or mixer tap.
