How to replace a ceramic cartridge in a tap
Most modern UK taps use a ceramic disc cartridge rather than a traditional rubber washer. When these wear out the tap will drip or feel stiff and gritty. The good news is cartridges are cheap and easy to swap — you just need to match the old one at a plumbers merchant. This guide walks you through the process step by step.
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Turn off the water supply to the tap — there should be an isolation valve under the sink with a screw slot. Turn it 90° with a flathead screwdriver. If there is no isolation valve, turn off the main stopcock.
Open the tap fully to release any remaining pressure in the pipe.
Remove the tap handle — look for a small screw hidden under a decorative cap on top of the handle. Pop the cap off with a flathead screwdriver and undo the screw (usually crosshead or Allen key).
Lift the handle off. You will now see the cartridge body — it may have a retaining nut or sleeve holding it in place. Use an adjustable spanner to unscrew it, turning anticlockwise.
Pull the cartridge straight out of the tap body. Take it with you to a plumbers merchant or builders' merchant to get an exact match — cartridges come in many sizes and styles.
Fit the new cartridge, making sure any orientation notch or tab lines up correctly. Press it firmly into place.
Refit the retaining nut and tighten firmly — don't overtighten or you risk cracking the tap body.
Refit the handle and decorative cap. Slowly turn the isolation valve back on. Check for leaks before refitting any cupboard panels.
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Frequently asked questions
How do I know if my tap has a cartridge or a washer?
Taps with a quarter-turn action (90° from off to fully on) use ceramic cartridges. Taps that require multiple turns to open fully use rubber washers. Most taps installed after 2000 are cartridge type.
Can I buy a replacement cartridge at a DIY store?
Sometimes, but plumbers merchants carry a much wider range. Take the old cartridge with you — they can match it on the spot. Knowing the tap brand also helps.
My tap has two handles — do I replace both cartridges?
Only replace the side that is dripping (hot or cold). You can identify which by touching the pipe coming into each valve under the sink — hot pipe will be warm.