If you have a dripping kitchen tap, a faulty tap cartridge is often to blame. It’s also fairly easy to replace a kitchen tap cartridge yourself with a few basic tools.
The cartridge controls the flow and, in mixer taps, the blend of hot and cold water. Over time it may wear, become blocked with limescale, or fail mechanically – leaving you with a dripping tap, poor temperature control or a stiff handle. In this guide we will explain:
- The signs that a cartridge may need replacing
- The most common types of tap cartridges
- Step-by-step instructions to replace a tap cartridge yourself
What is a tap cartridge and what does it do?
The cartridge is the internal mechanism of a tap that regulates water flow and temperature. In single-handle mixer taps the cartridge is the moving part that opens, closes and mixes hot and cold water. Replacing a worn cartridge is often cheaper and easier than replacing the whole tap. Replacing the cartridge can stop leaks, restore smooth handle movement and improve temperature control.
Typical kitchen tap cartridges, shown in the open and closed positions
Common signs that a cartridge needs replacing
Watch for these signs that the cartridge is failing:
- Tap drips even when the handle is in the off position
- Handle is stiff or difficult to move
- Temperature control is erratic or the cold and hot sides do not mix properly
- Water pressure from the tap is weak without other supply problems
- Noise such as squealing when the tap is turned
- Visible leaks from the base of the spout or around the handle
Some of these faults are also caused by worn washers or damaged O-rings. A quick diagnosis usually shows whether the cartridge itself is at fault. If you are unsure, removing the cartridge for inspection will reveal visible wear, cracks or heavy limescale.
How often should you replace a tap cartridge?
There is no one right answer to this question, because lifespan depends on water quality, frequency of use and the quality of the original cartridge. As a general rule:
- Average lifespan is typically five to ten years
- Homes in hard water areas may need replacement sooner because of limescale
- You may need to replace the cartridge sooner if you notice symptoms such as persistent dripping or poor movement
Replacing the cartridge at first sign of failure helps avoid wasted water and the risk of further damage to the tap or surrounding fittings.
Types of kitchen tap cartridges
There are several different cartridge designs, so make sure you know which type you need. The most common types in UK kitchens are described below.
Ceramic disc cartridges
Ceramic disc cartridges are very common in modern mixer taps. They consist of two ceramic discs that slide over each other to control flow and temperature. They generally work better than older washer designs, although heavy limescale can impair their movement, so regular cleaning in hard water areas helps.
Compression washer cartridges
These are the older style found in traditional taps where a rubber washer is pressed down to stop flow. They are simple and inexpensive to repair but wear faster than ceramic discs. If you have a tap that needs repeated washer changes, it may be worth upgrading to a cartridge type that is easier to maintain.
Monobloc and single-lever mixer cartridges
Single-lever mixer taps use a monobloc cartridge that combines flow and temperature control in one unit. These cartridges vary by manufacturer and may be proprietary, so identifying the tap brand or model often matters when sourcing a replacement.
Thermostatic and flow-limiting cartridges
Specialist cartridges are used in thermostatic taps and energy-efficient fittings. Thermostatic cartridges maintain a set temperature and are commonly used in showers and some kitchen tap designs. Flow-limiting cartridges restrict maximum flow to save water. If your tap has one of these features, be sure to use a compatible replacement.
How to identify the cartridge in your tap
To identify the cartridge type:
- Check the tap brand and model number, often found under the handle or on the underside of the spout
- Compare the removed cartridge to images from manufacturers or retailers
- Take the old cartridge to a local plumbing merchant or supplier for a match
Retailers such as Screwfix and B&Q list cartridge replacements by brand and model which can help you match the correct part. Manufacturer websites such as Grohe and Bristan provide parts diagrams for many tap models.
Tools and materials you will need
- Adjustable spanner
- Allan key or screwdriver to remove the handle (depending on the tap)
- Replacement cartridge matched to your tap
- Cloth or towel to protect finishes
- Small brush and white vinegar for cleaning limescale
- PTFE tape if any threaded joints require resealing
Step-by-step guide to replacing a kitchen tap cartridge
- Turn off the water supply to the tap. Most kitchen taps have isolating valves under the sink. If there are no isolating valves, turn off the mains water. Open the tap to relieve pressure.
- Place a cloth in the sink to protect the surface and catch small parts (it’s also a good idea to plug the sink so you don’t lose any small screws)
- Remove the handle. This usually involves lifting off a decorative cap and undoing a retaining screw or Allen bolt. Keep small screws safe.
- Remove any trim or collar to expose the cartridge retaining nut. Some designs have a visible C-clip or top retaining nut.
- Unscrew the retaining nut or clip and carefully lift out the old cartridge. Note the orientation of the cartridge for correct reassembly.
- Inspect the housing and clean any limescale or debris. A vinegar soak and a soft brush will help remove deposits that might prevent a good seal.
- Fit the new cartridge in the same orientation as the old one. Do not force the part into place; it should sit comfortably in the housing.
- Refit the retaining nut or clip and reassemble the tap handle and trim.
- Turn the water supply back on and test the tap. Check for leaks, smooth operation and correct temperature control.
- If there is any leak from thread joints, isolate the water and apply PTFE tape to threaded connections before retesting.
Cleaning and short-term repair options
In some cases the cartridge might just need a good clean rather than a full replacement. If the problem is limescale build-up, removing the cartridge and soaking it in white vinegar can improve movement and sealing. Rinse thoroughly and reinstall. This is only a short-term fix in hard water areas, but it may extend the cartridge life.
If the handle is stiff because of debris or grit, a clean and light lubrication of accessible moving parts may restore smooth action. Avoid petroleum-based lubricants that could damage seals.
When to call a professional
You can replace most common cartridges as a confident DIYer. Call a plumber if:
- The tap is connected to complex plumbing such as integral filters or instant hot water units
- There is damage to the tap body or the cartridge seating that requires professional repair
- You do not have isolating valves and you are uncomfortable turning off the mains supply
- There is evidence of larger water damage or persistent leaks after replacement
Costs and sourcing replacement cartridges in the UK
Replacement cartridges vary in price. Some generic ceramic cartridges can cost under £10, while branded or thermostatic cartridges cost upwards of £100. Popular DIY shops like as Screwfix and B&Q usually stock a wide range of parts. Amazon also sell plumbing supplies, although the quality can vary. Manufacturer websites often list genuine spares for best compatibility. For plumbing safety and certified installers you can also consult WaterSafe for registered plumbers and guidance.
Frequently asked questions
Can I use any cartridge in my tap?
Not usually. Many taps require a specific cartridge design or spline pattern. Always match the cartridge to the tap brand and model where possible. If you are unsure, take the old cartridge to a specialist merchant for identification.
How much does a replacement cartridge cost?
As mentioned above, simple ceramic cartridges are usually cheap – sometimes under £10 – while genuine branded parts and more complex thermostatic cartridges can be significantly more expensive. Labour costs will also apply if you use a plumber.
Is it worth replacing the cartridge or should I replace the whole tap?
Replacing the cartridge is usually the sensible first step. If the tap body is corroded or scratched, or if you want a different finish or style, replacing the whole tap may be more appropriate. If you have an older tap that has repeatedly failed, a full replacement is probably wise.
Can limescale ruin a cartridge?
Yes. Heavy limescale can prevent smooth movement and damage sealing faces. Regular descaling or installing a water softening solution can prolong cartridge life.
What to remember:
- Identify the correct cartridge type and brand before buying a replacement
- Isolate the water supply before you begin
- Keep small parts and screws safe during disassembly
- Clean away limescale and debris before fitting the new cartridge
- Test the tap and check for leaks once the tap is back together
- Check and de-scale cartridges regularly if you live in a hard water area
A failing kitchen tap cartridge is usually straightforward to diagnose and replace. Doing so can get your taps as good as new without needing to replace the entire unit. For complex cases or if you are uncertain about turning off supplies, contact a registered professional plumber.
