What is a Faucet Cartridge and How Does it Work?

Last Updated on November 16, 2021 by Bonnie C. Welling

Every machinery item has its working process. A faucet cartridge is such an item of a bathroom used to control water flow, and it is a one-handle faucet. Previously, dual-handle compression faucets were used mostly for this purpose. One handle was for cold water and the other one for hot water.

You can easily control the flow of cold or hot water using a single handle in a cartridge faucet. You may have an interest in the working process of a faucet cartridge. Here we are describing how does a faucet cartridge work. We hope this will meet your interest and help you to fix any errors in your faucet.

What Is A Faucet Cartridge?

You may have two cartridge-style faucets in your bathroom. Every faucet handle comes with its cartridge. A faucet cartridge is a replaceable water valve that controls the water flow to the faucet spout. It has inner-flow valves on the inside and outer-flow valves on the outside. When you turn the faucet, the valve moves and flows water through the tap to your sink.

Usually, a cartridge is made of plastic and comes with a metal retaining nut. In the case of compression faucets, they come with a metal valve, including a flat rubber washer.

Parts of A Faucet Cartridge

A faucet cartridge contains some parts and these are-

  • 2 check valves.
  • 1 balancing spool.
  • A temperature sensor and.
  • A ceramic.

How Does A Faucet Cartridge Work?

How Does A Faucet Cartridge Work

Cartridge faucets are the next generation of double-handled compression faucets. But nowadays, compression faucets are hard to find. There are two types of handles in compression faucets: one handle circulates cold water and another one circulates hot water. You have to turn the screw threads for tightening or losing the washer to control the water flow.

In cartridge faucets, it has only one handle which remains connected to the valve housing. Instead of two handles, you can easily control the flow of hot or cold water using this single handle when you turn off the faucet; the cartridge inside the housing blocks the water from flowing from both inlets.

There are strategic holes to allow both cold and hot water after turning on the faucet. But these strategic holes are designed so that they don’t allow both cold and hot water to flow together. If you want to get cold water, then you should rotate it in one direction. And for hot water, you have to turn it to the opposite.

Previously, metal was used to make the cartridge. But at present, most of the cartridges are made of plastic. But the water won’t stop flowing unless you use rubber gaskets in rubber O-rings and valve seats. As a result, your faucet will spray continuously.

Sometimes you may find cartridge valves in double-handled faucets. Identifying these types of faucets is very much comfortable. You can turn the compression faucet handle 360 degrees easily. But, you have to rotate the tap several times to get the water to fall entirely.

When you turn on the switch of hot or cold water, it circulates through the check valves. Then it flows the balancing spool of the cartridge. It controls the flow according to the pressure variation. Then the water flows through the thermostatic part. If you change the water temperature, the sensor will control it inside the cartridge. As a result, you will get your desired temperature of the water. The ceramic inside the cartridge determines the outlet of the water.

Why Do Faucet Cartridges Fail?

Your faucet cartridge may fail and create some problems. Dripping water makes noise, and if the water flows for a long time, it may damage your walls, floor, cabinets, or another area. A faucet cartridge may fail for several reasons. Here are some reasons:

Worn Washer

Each compression faucet comes with a washer installed inside. Usually, it is made of rubber. The tap may drip or leak if this washer is worn out. When water starts flowing, it pushes the washer against the valve seat and creates friction. As a result, the washer loses strength and fails.

Weak O-Ring

This is the most found piece in cartridge faucets. And, this piece is the most common reason for faucet leakage. This piece is used for sealing any gap between the faucet and cartridge. If the O-Ring fails, the faucet will get leaked. As a result, water will come out without any obstacle and damage your house. You can quickly fix this error by replacing it with a new one.

Loose Parts

Faucets are used equipment of a home continuously. As a result, the parts inside this can easily get loose. If it happens, the water will come out from the faucet base. Just observe the location where the water is coming out. Remove the faucet handle, then tighten that part that got loose.

Other Broken Parts or Pipes

If you cannot find out the place of water leakage above your sink, then most probably your pipe or underneath pipes have been broken. In this case, you should call a professional who knows how to fix this well.


How does the inside of hot or cold inside come out?

The water flows through the valves and balancing spool. Then it goes to the thermostatic part. This part controls the temperature of the water.

Can I repair the faucet cartridge?

There are few types of faults in a faucet cartridge. If the O-ring fails or the washer is worn or any part gets loosen, then you can fix this easily. But, if any pipe breaks, it would be better if you call any professional to fix the problem.


A faucet is an essential part of a bathroom. As the cartridge faucets come with a double-handle, so these are much more convenient rather than compression faucets. The working process of a faucet cartridge is so much easier. We have discussed “How does a faucet cartridge work” here in brief. This article is to inform you about the working process and make you learn how to fix any problems. We hope this will help you enough if you face any issues.

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