I have a Delta shower/tub valve which controls water flow to our tub (with a diverter that can be switched to shower). There is a slow leak from the tub faucet which I am trying to repair. This valve was installed less than 6 months ago, so the leak is a bit surprising.

assembled valve

After turning off our water lines, I disassembled the valve and removed the cartridge. The cartridge and o-rings seemed ok and not worn (to be expected).

cartridge removed

However, the leak was still occurring from behind where the cartridge was. On the right side of this image, you can see some water leaking from the cold water supply line. When this image was taken, the water supply was turned off and the bathroom sink did not have any water pressure or leaking.

  • Is this the same leak that is causing my faucet to drip? (I am assuming so, with the water flowing through the cartridge somehow?) Or is the cartridge still possibly to blame?

  • What could be causing a leak from further back than the cartridge?

  • What can I do to fix this?

2 Answers 2


What you see in the picture is just water that was in your pipe dripping out. After shutting off water, there is always a small amount coming out.

If the leak is external (in front of your tiles), i would say it is your cartridge or seals of your faucet being faulty. If it is behind the tiles, the soldering of your pipe must have given up which is very bad news. Is your cement board wet?

If you have another bath with a compatible faucet, swapping them to isolate the problem. Else get anothe faucet to try it out.

On a side note, I noticed the Redgard water proofing layer didn't fully cover all the way to the edge of the hole. You might want to touch up and make sure water don't go behind. Usually water damage happens at these openings.

  • I think this was indeed just a little water still coming out from the pipe. After reassembling the faucet, the issue seems to have gone away. Thanks for your answer. Oct 13, 2020 at 19:08

What is on the other side of the wall? Sometimes it is easier to do the repair from behind especially if it drywall

  • good point - However in this case the other side is not really accessible Oct 13, 2020 at 19:07

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