How to Replace a Faucet Cartridge

Step 1: Make sure the cartridge is the likely problem

1. Look for symptoms a cartridge commonly causes: a faucet that drips when fully off, a handle that feels stiff or loose, poor hot-cold control, or weak flow that is not fixed by cleaning the aerator.
2. Confirm the problem is at one faucet, not throughout the house. A whole-house pressure issue points somewhere else.
3. Check that the faucet body itself is not cracked and that water is not leaking from supply lines under the sink.
4. If you already bought a replacement, compare it to the old faucet style before taking anything apart so you know you have a likely match.

If it works: The symptoms point to an internal faucet control problem, and replacing the cartridge is a reasonable next step.

If it doesn’t: If the leak is coming from a supply connection, the spout base, or a cracked faucet body, fix that issue first instead of replacing the cartridge.

Step 2: Shut off water and open the faucet

1. Close the hot and cold shutoff valves under the sink by turning them clockwise.
2. Turn the faucet on to relieve pressure and confirm the water is off.
3. Put a towel in the sink or over the drain so small screws and clips do not fall in.
4. Lay a rag around finished trim if you may use pliers nearby.

Step 3: Remove the handle and trim

1. Pry off the decorative cap if there is one, or locate the small set screw on the handle.
2. Remove the handle screw with a screwdriver or Allen key, then lift the handle off.
3. Unscrew or carefully lift off the trim sleeve, bonnet, or retaining cover to expose the cartridge area.
4. Set parts down in order so reassembly is easier.

Step 4: Remove the old cartridge

1. Take out the retaining clip, retaining nut, or bonnet that locks the cartridge in place.
2. Note the cartridge orientation before pulling it out. A quick photo helps.
3. Pull the cartridge straight up or straight out, depending on the faucet design. Use adjustable pliers carefully on the cartridge stem if needed.
4. If the cartridge is seized, use a cartridge puller rather than twisting hard on the faucet body.

Step 5: Clean the valve body and install the new cartridge

1. Wipe out the cartridge cavity with a rag and remove loose debris or scale with a small brush.
2. Use a little vinegar on mineral buildup, then wipe the area clean so the new seals sit properly.
3. Compare the new cartridge to the old one one more time for stem shape, length, and port layout.
4. Insert the new cartridge in the same orientation as the old one, making sure tabs or alignment marks seat correctly.
5. Reinstall the retaining clip, nut, or bonnet, then put the trim and handle back on.

If it doesn’t: If the cartridge does not seat fully, remove it and check orientation, debris in the valve body, or a mismatch between old and new parts.

Step 6: Turn the water back on and test the repair

1. Open the shutoff valves slowly under the sink.
2. Run the faucet through full hot and cold positions and check that the handle moves smoothly.
3. Turn the faucet off and watch the spout for several minutes to make sure dripping has stopped.
4. Check around the handle, trim, and under the sink for leaks while the faucet is on and off.
5. Use the faucet normally a few times over the next day to confirm the repair holds in real use.

If it works: The faucet turns on and off normally, flow is steady, and there are no leaks or drips during normal use.

If it doesn’t: If the faucet still drips or the handle does not control water correctly, remove the handle again and confirm the cartridge is the correct part and installed in the right orientation.