Why Is Water Coming Out Of The Shower Head While Filling Bathtub?

Have you noticed that water is coming out of your shower head while you’re filling your bathtub? If your shower and tub are combined, and the plumbing is functioning correctly, only one faucet should be running at a time. If the issue is not addressed, over time this could add up to paying more for your water bill and loss of water pressure from your shower head.

Water shouldn’t be coming out of your shower head until you pull up the handle on your tub’s spout to change your water source. So, if water is coming out without having done that, you may have an issue with your shower diverter valve. The valve works as the name indicates by diverting or redirecting water from coming down the tub faucet to flow up to the shower head.

Pulling the knob on the tub’s faucet makes the diverter turn inside the pipe to block the water from coming out of the tub. However, time and build up can wear down the diverter from properly turning which could lead to water coming out of both fixtures at the same time.

A useful tip to avoid wearing out your diverter and ensure that it continues to work is to let the flow of water return to the bathtub spout once you’re done taking a shower before you turn off the faucet.

To clean and remove any build-up that may be affecting the diverter from working correctly, you’ll have to take apart the valve assembly.

You’ll need to have:

  • Screwdriver
  • Wire brush
  • White vinegar

Take the cap off the tub’s faucet, and when you remove the handle, the diverter valve should be visible. Locate the nut on the stem and unscrew it as well as the washer and screw. Check these pieces to see if they look worn down and replace if necessary.

Dip the small wire brush in vinegar and scrub any debris or buildup from the valve. After the valve has dried, put it back together and run the faucet in the tub to see if this has stopped water coming out of the shower head when you’re filling the bathtub.

If upon inspection, there is way too much gunk for you to remove completely or you discover that it has become damaged, then you will probably need a new valve.


  1. I have a new Moen water assembly on my bathtub and water is pouring out of the shower head on your head when filling the tub. Are all Moen diverter valves made this crude?

    1. I’m assuming the diverter is on the tub spout? No Moen is usually a high-quality manufacturer. You may have gotten a lemon.

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