How to Repair Leaking Shower Mixer Valve

By Ben Victor

Updated: 20th August 2023

Contents show

A leaking shower mixer valve is not only a nuisance but can also lead to water wastage and potential damage to your bathroom.

Fortunately, with the right tools and a bit of know-how, you can tackle this problem yourself.

In this article, we’ll walk you through the steps to repair a leaking shower mixer valve.

Repair Leaking Shower Mixer Valve — Credit: DIM Tips

How to Repair Your Leaking Shower Mixer Valve

1. Gather Your Tools

Before you begin, ensure you have the following tools and materials on hand:

Adjustable wrench or spanner
Screwdriver (both flathead and Phillips)
Replacement cartridge or washer (specific to your valve model)
Plumber’s tape
Plumber’s grease
Towels or rags

2. Turn Off the Water Supply

Safety first! Before you start any plumbing repair, always turn off the water supply to prevent flooding. This can usually be done at the main water valve or at the shut-off valves located near the shower.

3. Remove the Handle

Start by removing the handle cap, which is often a decorative piece that hides the screw.
Using your screwdriver, unscrew and remove the handle. Keep all parts and screws in a safe place for reassembly.

4. Access the Mixer Valve

With the handle removed, you should now see the mixer valve’s stem.
Depending on your shower design, you might need to remove a trim plate or escutcheon to fully access the valve.

5. Inspect the Valve

Before you replace anything, take a moment to inspect the valve.

Look for signs of wear, corrosion, or damage.

This will give you an idea of what needs replacing.

6. Replace the Cartridge or Washer

If your mixer valve uses a cartridge system:
- Use your wrench to carefully unscrew and remove the old cartridge.
- Apply a small amount of plumber’s grease to the new cartridge’s O-rings.
- Insert the new cartridge, ensuring it aligns correctly with the valve body.
If your mixer valve uses a washer:
- Unscrew the valve stem using your wrench.
- Replace the old washer with a new one.
- Reassemble the valve stem.

7. Reassemble the Shower

If you removed a trim plate or escutcheon, replace it now.
Reattach the handle, ensuring it’s securely tightened.
Replace the handle cap or any decorative pieces.

8. Turn On the Water Supply

Slowly turn the water supply back on and check for any leaks.

Test the shower’s functionality to ensure everything is working as it should.

9. Final Checks

Run the shower for a few minutes and check for any drips or leaks.

If everything looks good, congratulations!

You’ve successfully repaired your leaking shower mixer valve.

Wrapping Up

Repairing a leaking shower mixer valve can seem daunting, but with the right tools and a step-by-step approach, it’s a task that many homeowners can tackle on their own.

Remember, if you’re ever in doubt or the problem persists, don’t hesitate to call a professional plumber.