Symptoms
- Drip from the spout regardless of handle position
- Handle feels loose or wobbly
- Temperature is hard to fine-tune
- Faucet is more than 8–10 years old
Likely causes
- CommonWorn cartridge sealsRubber seals inside the cartridge degrade with age and mineral exposure.
- CommonMineral scale inside the cartridgeBuildup can prevent the cartridge from sealing even if seals are intact.
- PossibleScratched cartridge housingGrit in the water can score the internal surfaces over time.
- Less commonWrong cartridge installed previouslyA mismatched replacement can fail early.
What to do
- Shut off the hot and cold water supply under the sink.
- Remove the decorative cap, handle screw, and handle.
- Remove the retaining clip or nut holding the cartridge in place, keeping small parts organized.
- Pull the old cartridge straight up and out; needle-nose pliers can help grip a stuck one.
- Match the old cartridge exactly by brand and model number before buying a replacement, since cartridges are not universal.
- Insert the new cartridge in the same orientation as the old one and secure the retaining clip or nut.
- Reattach the handle, turn the water back on slowly, and run hot and cold for a minute to clear debris.
- Check for leaks at the base and under the sink after the first several uses.
Tools and parts
- Adjustable wrench
- Screwdriver
- Needle-nose pliers
Faucet cartridge (brand-matched)Search: “replacement faucet cartridge [brand and model]”
When to call a pro
Call a plumber if you can't identify the exact cartridge needed or the faucet is a specialty/commercial model.
Safety
Generally low risk
Generally low risk for a careful person. Stop if anything looks different from what this guide describes.