What a faucet cartridge is and why you need to replace it

A faucet cartridge is the part inside your faucet that controls water flow and temperature. It looks like a small cylinder or spool, usually made of plastic or brass, and it sits behind the handle. When you turn the handle, you are moving the cartridge, which opens and closes the water passages. Over time, mineral buildup, wear, or damage makes the cartridge stick, leak, or fail to shut off completely.

Replacing the cartridge is cheaper and faster than replacing the entire faucet. Most cartridges cost between $15 and $75, and the job takes 30 minutes to an hour if you have the right tools. You do not need a plumber for this repair.

Key Takeaways

  • Identify your faucet brand and model number before you buy a replacement cartridge, because cartridges are not universal.
  • Turn off the water supply under the sink or at the main shutoff valve before you start, and open the faucet to release pressure.
  • Remove the handle by prying off the cap or unscrewing the set screw, then unscrew the cartridge body with a cartridge puller tool.
  • Insert the new cartridge in the same orientation as the old one, reassemble the handle, and test for leaks before you close up the cabinet.
  • If the cartridge is stuck, soak the faucet body in white vinegar overnight to dissolve mineral deposits.

Find your faucet brand and cartridge model number

Cartridges are brand-specific. A Moen cartridge will not fit a Delta faucet, and a Kohler cartridge will not work in a Pfister. Look under the sink or on the faucet body for the brand name stamped or printed on the metal. Common brands are Moen, Delta, Kohler, Pfister, and Grohe.

Once you know the brand, look for the model number. It is usually on a sticker under the sink, on the faucet body itself, or in the paperwork that came with the faucet. Write down the full model number. Go to the manufacturer's website or call their customer service line with the model number, and they will tell you which cartridge you need. You can also take a photo of the old cartridge to the hardware store and ask the staff to match it.

Turn off the water and release the pressure

Look under the sink for two shutoff valves, one for hot water and one for cold. Turn both clockwise until they stop. If you cannot find shutoff valves under the sink, turn off the main water supply to the house. This is usually a valve near the water meter or where the main line enters the house.

After the water is off, open the faucet handle all the way and let any remaining water drain out. This step is important because it releases pressure in the lines and prevents water from spraying when you remove the cartridge.

Remove the handle and expose the cartridge

Look at the top of the handle. Most faucets have a small cap or plug covering a screw. Pry this cap off with a flat-head screwdriver or a plastic pry tool. Underneath is a set screw. Unscrew it with an Allen wrench or Phillips screwdriver, depending on the type. Keep the screw in a small container so you do not lose it.

Pull the handle straight up and off. You may need to wiggle it gently. Once the handle is off, you will see the cartridge body, which is usually a hexagonal or round piece of metal or plastic sticking up from the faucet body. Some faucets have a decorative collar or trim ring around the cartridge. If yours does, unscrew it by hand or with a wrench.

Remove the old cartridge with a cartridge puller

A cartridge puller is a tool that grips the cartridge and pulls it straight out. You can rent one from a hardware store for a few dollars or buy one for $10 to $20. It looks like a corkscrew with a handle and two or three arms that clamp around the cartridge.

Screw the puller onto the cartridge until the arms grip it firmly. Turn the handle clockwise and pull up slowly. The cartridge should slide out. If it is stuck, stop and soak the faucet body in white vinegar for several hours or overnight. The vinegar dissolves mineral deposits that are holding the cartridge in place. Try again after soaking.

Once the cartridge is out, look at how it is oriented. The cartridge has a flat side or a notch that lines up with a slot in the faucet body. Note this orientation before you set the old cartridge down, because you will need to insert the new one the same way.

Install the new cartridge and reassemble

Before you insert the new cartridge, check that it matches the old one exactly. Hold them side by side and compare the shape, size, and the position of the flat side or notch. If they do not match, you have the wrong cartridge. Go back to the store and exchange it.

Insert the new cartridge into the faucet body, aligning the flat side or notch with the slot. Push it in straight and all the way down until it sits flush with the faucet body. Screw the collar or trim ring back on by hand. Slide the handle back onto the cartridge, making sure it is centered. Screw the set screw back in and tighten it firmly, then snap the cap back on.

Test for leaks and turn the water back on

Turn the shutoff valves back on by turning them counterclockwise. Turn slowly so the pressure builds gradually and does not shock the lines. Open the faucet handle and let the water run for 30 seconds. Check under the sink for drips around the cartridge body and at the shutoff valves.

If water is dripping from the cartridge body, the cartridge may not be seated all the way down. Turn the water off again, remove the handle and collar, and push the cartridge down a little further. If water is dripping from the shutoff valves, tighten them a quarter turn with a wrench. If the faucet is still leaking after these steps, the new cartridge may be defective. Return it and get a replacement.

Frequently Asked Questions

Do I need a cartridge puller, or can I pull the cartridge out by hand?

A cartridge puller is the right tool for the job. Trying to pull by hand risks damaging the cartridge or the faucet body. Pullers are cheap to rent and take the guesswork out of the job. If the cartridge is stuck, soaking in vinegar first makes it easier to remove.

What if I install the cartridge backwards?

The handle will work, but hot and cold will be reversed — turning the handle one way gives you hot water instead of cold. Turn the water off, remove the handle and collar, pull the cartridge out, rotate it 180 degrees, and push it back in. This happens often and is straightforward to fix.

Can I replace just the rubber seals inside the cartridge instead of the whole cartridge?

Some cartridges have replaceable seals, but most do not. The seals are usually bonded to the cartridge body and cannot be separated. Replacing the whole cartridge is the standard repair. Seal kits exist for a few older models, but they are rare and harder to find than new cartridges.

How long does a faucet cartridge usually last?

Most cartridges last 10 to 15 years with normal use. Hard water, high water pressure, and frequent use can shorten the lifespan. If your faucet is leaking or the handle is sticking after five years, the cartridge may be wearing out.

What should I do with the old cartridge?

Throw it in the trash. Cartridges are not recyclable in most programs. Some hardware stores will take old faucet parts, so you can ask when you buy the new cartridge, but it is not required.