By Miles SinclairUpdated November 2026
To repair a leaky bathtub faucet single handle, you shut off the water, pull the handle, remove the cap and retaining clip, and replace the cartridge that controls the flow. Most drips come from a worn cartridge, so this repair usually takes under an hour with basic hand tools. The steps below cover identifying the cause, taking the faucet apart and reassembling it without damaging the finish.
Confirm the Cartridge Is the Problem
A single-handle tub faucet has one cartridge inside the valve body. When the rubber seals or ceramic discs wear out, water slips past them even with the handle off, which is why the spout keeps dripping. Before you take anything apart, check the diverter as well. If water leaks from the shower head when the tub spout is in use, the diverter may be the culprit instead.
Shopping for one? See our guide: 5 Best Leaky Faucet Repair Bathtub Kits for Common Leaks and Drips (2026).
Shut Off the Water and Remove the Handle
Close the main supply or the shutoff valves under the tub, then open the faucet briefly to drain the lines. Use this sequence:
- Turn the handle to the on position and pry off the decorative index button or cap with a flathead screwdriver.
- Remove the handle screw, usually a Phillips or Allen-style screw, and lift the handle straight off.
- Unscrew the metal escutcheon or trim sleeve. Wrap its edge with painter’s tape first to protect the finish.
- Pull out the retaining clip at the base of the cartridge. Note its orientation before removing it.
Remove and Replace the Cartridge
Grip the cartridge stem with pliers wrapped in a rag and pull it straight out. Some cartridges are held in place by a locknut, so loosen that first if the cartridge will not slide free. Compare the old cartridge with its replacement. The stem height, the number of notches and the brand markings must match exactly, since a mismatched cartridge will not seal or align correctly. Many manufacturers specify the same cartridge model for several decades of faucets, so bring the old part to a supply store if you are unsure.
Before installing the new cartridge, clean the valve seat inside the body with a soft cloth. Grit left behind is a common reason a new cartridge still drips. Coat the O-rings with plumber’s silicone grease, seat the cartridge with its alignment tab in the correct slot, and reinstall the retaining clip.
Reassemble and Test the Faucet
Reverse the disassembly order: escutcheon, handle, screw and cap. Restore the water supply slowly, then run the handle through its full range of motion. Check for drips at the spout and at the base of the handle. If the handle feels stiff, the locknut may be overtightened, so back it off slightly. Let the water run for a minute to clear any debris from the lines.
Recommended gear
- Plumber’s silicone grease: keeps the O-rings lubricated so the cartridge slides in without tearing them. View on Amazon
- Faucet cartridge puller: grips a stuck cartridge stem so you can remove it without damaging the valve body. View on Amazon
- Painter’s tape and a soft cloth: protect chrome and brass finishes from scratches during disassembly. View on Amazon
Common mistakes
- Buying a cartridge by appearance alone. Match the model number and stem pattern instead.
- Forgetting to shut off the water fully, which leads to a sudden spray.
- Overtightening the handle screw, which can crack the plastic index cap.
- Skipping the valve seat cleanup, so debris keeps the new cartridge from sealing.
- Using pliers directly on the chrome finish without a cloth or tape.
For a broader walkthrough of tub repairs, see How to Repair a Leaky Faucet in Bathtub: Step-by-Step Fix (2026) and Repair Bathtub Faucet Leak: A Step-by-Step Guide to Stop Drips. If your faucet is a Delta model, Delta Single Handle Faucet Repair Kit Review: Features and Performance covers the parts involved.
FAQ
Can I repair a single-handle tub faucet without replacing the whole unit?
Yes. In most cases only the cartridge needs replacing, and the valve body, spout and handle can stay in place. Replacing the full faucet is rarely necessary for a simple drip.
How do I know which cartridge to buy?
Check the brand name and model number stamped on the old cartridge or listed in the faucet’s manual. Bring the old cartridge to a hardware store so you can compare stem height and notch count.
Why does my faucet still drip after replacing the cartridge?
The most common cause is debris on the valve seat or a cartridge that was not seated fully. Remove the cartridge, clean the seat, and check that the alignment tab sits in the correct slot.
Conclusion
Replacing the cartridge is the most reliable way to repair a leaky bathtub faucet single handle, and it is a job most homeowners can finish in an afternoon. Shut off the water, match the new part carefully and test the faucet before closing everything up. If the leak continues or the valve body is corroded, consult a licensed plumber.
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About Miles Sinclair
Miles Sinclair is part of our editorial team and reviews and edits our kitchen faucets & sinks guides, checking product details against manufacturer specifications and owner feedback.
