A worn cartridge is the most common reason a kitchen faucet won't turn off completely.
- Turn off the water supply before attempting any repair.
- Regular cleaning and replacing the cartridge every few years can prevent this issue.
- If the faucet is old or parts are unavailable, consider replacing the whole unit.
Why won't my kitchen faucet turn off completely?
The most common cause is a worn-out cartridge or valve stem. Mineral deposits can also block the internal seals. A damaged O-ring or seat can prevent a tight shutoff. Sometimes the handle is loose or misaligned, so it doesn't fully engage the valve. In rare cases, the faucet body itself is cracked or corroded.
How to fix a kitchen faucet that won't shut off
First, turn off the water supply valves under the sink. Open the faucet to release remaining water pressure. Remove the handle with a screwdriver or Allen wrench. Pull out the cartridge or valve stem using pliers. Inspect it for cracks, wear, or mineral buildup. Replace the cartridge with an exact match from the manufacturer. Reassemble the faucet and turn the water back on.
How to prevent a faucet from sticking or leaking
Clean the aerator regularly to remove sediment. Avoid using excessive force when turning the handle. Install a water softener if you have hard water. Lubricate the O-rings with plumber's grease during maintenance. Replace the cartridge proactively every five to seven years.
When to replace the faucet instead of repairing it
If the faucet body is cracked or corroded, replacement is safer. If the cartridge is no longer available, a new faucet makes sense. If you've replaced parts twice and the problem persists, consider a new unit. If the faucet is over 15 years old, replacement is often more cost-effective.
When to call a professional plumber
Call a plumber if you're not comfortable disassembling the faucet. If the water supply valves are stuck or leaking, get professional help. If the leak continues after replacing the cartridge, a plumber can diagnose deeper issues. If you have a complex faucet with multiple handles or a pull-down sprayer, professional service is wise.