Tap Cartridge Types Explained: Ceramic vs Compression

When a tap starts dripping, the culprit is almost always the cartridge or valve inside. Knowing whether your tap uses a ceramic disc cartridge or a compression valve makes repairs far simpler, and it helps you choose the right replacement before you even pick up a spanner. Here's a practical guide to the two most common types found in UK homes.

What Is a Tap Cartridge?

The cartridge is the internal mechanism that controls the flow of water when you turn the handle or lift the lever. It sits inside the tap body and opens and closes the water supply each time you use the tap. Because it moves every day, it eventually wears out — and when it does, the telltale sign is a drip that won't stop, no matter how tightly you close the tap.

There are two broad families of tap valves: traditional compression valves and modern ceramic disc cartridges. Both do the same job, but they work in very different ways.

How Compression Valves Work

Compression valves are the old-school design, found in many older pillar taps and traditional crosshead-style taps. Turning the handle raises or lowers a rubber washer (often called a jumper washer) against a valve seat inside the tap body. When you tighten the tap, the washer presses down and stops the water flow.

The main drawback is wear. Every turn grinds the rubber washer against a metal seat, which gradually degrades both parts. This is why compression taps are the ones most likely to develop a persistent drip — usually fixable by replacing a washer costing pennies, but the valve seat itself can also become scored and may need re-facing or replacing.

How Ceramic Disc Cartridges Work

Ceramic cartridges are the modern standard, used in most contemporary mixer taps and monobloc levers. Inside the cartridge are two precision-ground ceramic discs with holes that align or misalign as you turn the handle. A quarter-turn opens the flow fully; another quarter-turn closes it.

Because the ceramic discs are extremely hard and glide rather than grind, they wear slowly and rarely need servicing. When they do fail, it's usually the seals around the discs rather than the ceramics themselves — and the usual fix is to swap the whole cartridge for a matched replacement.

Common signs of a worn ceramic cartridge

  • A drip from the spout even when the lever is fully closed
  • A tap that requires increasingly forceful movement to shut off
  • Grinding or stiffness when operating the lever
  • Water escaping around the base of the handle

Which Type Do You Have?

A quick check saves you buying the wrong part:

  1. Look at the handle. Crosshead or "faucet-style" handles usually mean compression valves; a single lever that lifts and swivels almost always means ceramic cartridges.
  2. Count the turns. Compression taps typically need several full rotations to open; ceramic taps need only a quarter or half turn.
  3. Check the tap's age and brand. Modern mixer taps sold today almost universally use ceramic technology.
  4. Unscrew and inspect. A compression valve has a visible rubber washer on a spindle; a ceramic cartridge is a sealed cylindrical unit, often with a plastic or brass body.

Choosing the Right Replacement

When replacing a ceramic cartridge, size and orientation matter. Cartridges come in different heights, spindle sizes, and hot or cold configurations, so take the old part with you or measure it carefully. Compression tap repairs are more forgiving — a standard washer kit covers most situations — but check whether your tap has a replaceable valve seat before assuming the washer alone is the fix.

Whichever system your tap uses, both types are repairable with basic tools and a little patience. The key is diagnosing correctly first: rubber washers for the traditionalists, matched ceramic cartridges for the moderns, and a drip-free tap either way.

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