Caleb MorganBy Caleb Morgan

Updated November 2026

To repair a bathtub faucet leak, you need to find where the water is escaping, shut off the supply, and replace the worn part causing it. Most drips come from a worn cartridge, a failed washer, or a damaged valve seat, and each of these can be swapped with a basic tool set in an afternoon. This guide walks through the process so you can stop the leak and avoid the water damage that builds up over time.

Identify Where the Leak Is Coming From

Before you take anything apart, figure out which kind of leak you have. A faucet that drips from the spout when it is closed usually points to a worn cartridge or washer. Water seeping from the base of the handle or around the escutcheon plate often means a failed O-ring or packing nut. A leak that shows up only when the diverter is engaged points to the diverter, not the valve.

Shopping for one? See our guide: 5 Best Leaky Faucet Repair Bathtub Kits for Common Leaks and Drips (2026).

Shut Off the Water and Prepare the Work Area

Turn off the water at the shutoff valves under the tub or at the main supply. Then open the faucet to drain any remaining water. Place a towel or rubber mat in the tub to protect the finish and keep small parts from disappearing down the drain.

  1. Close the hot and cold shutoff valves, or the main water supply.
  2. Open the tub faucet to relieve pressure and drain the lines.
  3. Plug the drain or cover it with a cloth.
  4. Gather a screwdriver set, adjustable wrench, Allen keys, plumber’s grease, and replacement parts.

Replace the Cartridge or Washers

Most single-handle and many two-handle bathtub faucets use a cartridge or a set of compression washers. Remove the handle screw, take off the trim, and unscrew the retaining nut or cartridge clip. Pull the old cartridge straight out and compare it to the new one so the replacement matches the brand and model. Apply a thin layer of plumber’s grease to the O-rings before installing the new part, then reassemble in reverse order.

Check the Valve Seat

If the leak continues after the new cartridge is in, the valve seat may be scored or corroded. Use a seat wrench to remove it and inspect the surface. Light pitting can often be smoothed, but deep grooves usually mean the valve body needs replacing.

Test the Repair and Confirm the Leak Is Stopped

Turn the water back on slowly, first at the shutoff valves and then at the faucet. Run the hot and cold sides and the diverter for at least a minute each. Watch the spout closely after shutting the handle, since a small drip may take several minutes to appear.

Common Mistakes to Avoid

  • Buying a replacement part without noting the brand and model number.
  • Overtightening the retaining nut, which can crack the valve body.
  • Skipping plumber’s grease, which leads to torn O-rings and early failure.
  • Forgetting to cover the drain, which can lose small screws or clips.
  • Reinstalling a worn valve seat and expecting a lasting fix.
  • Plumber’s grease: lubricates O-rings and prevents tearing during cartridge installation. View on Amazon
  • Valve seat wrench set: removes and reinstalls stubborn seats without damaging the valve body. View on Amazon

If you want model-specific guidance, these related articles on the site cover common brands: Delta Bathtub Faucet Repair Kit: Step-by-Step Fix for Leaks and Drips and Kohler Artifacts Bathtub Faucet: Identify, Repair and Maintain It (Step-by-Step). For a diverter problem specifically, see Bathtub Faucet Diverter Repair Kit: 6 Best Picks for Leaks (2026). If the leak is coming from a tub spout, Repair Tub Faucet Drip: A Step-by-Step Guide to Stop Leaks (2026) walks through that case.

FAQ

Why does my bathtub faucet keep dripping after I replace the washers?

The valve seat is often the cause. If it is scored or corroded, new washers or a cartridge will not seal properly, so inspect and replace the seat if needed.

Do I need to shut off the main water supply to fix a tub faucet?

Not always. Many bathtubs have individual shutoff valves on the supply lines, but if they are old or leaking, shutting off the main is the safer choice.

When should I call a professional plumber?

Call a licensed plumber if the valve body is cracked, the supply pipes are corroded, or you notice water damage behind the wall. Those problems go beyond a standard faucet repair.

Conclusion

A bathtub faucet leak usually comes down to one worn part, and finding it is most of the job. Shut off the water, identify the leak source, and replace the cartridge, washers, or seat as needed. Test the repair thoroughly before you close up the wall or trim.

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Caleb Morgan

About Caleb Morgan

Caleb Morgan is part of our editorial team and reviews and edits our kitchen faucets & sinks guides, checking product details against manufacturer specifications and owner feedback.