I just discovered that one of my tub valves was leaking inside the wall for quite some time, given that the wood floor in the adjacent closet has gone moldy and the drywall beside the tub out past all the tile is soft. It was probably 1 drop every second.

Last night I installed a couple ball valves so I didn't have to leave the whole house turned off while I mess around with this, but I am not 100% what to do next. The leak is coming from some sort of adjustment valve right under the cold water handle. I don't know what this thing does or what it is called so I am having trouble searching for a solution. It is accessible from the tub side through a hole in the valve trim plate, right underneath the handle. See the hole in the photo below. Anybody know what this is and how to repair it before I just start taking it all apart?

Valve Handle

The drywall behind the thickset mortar bed tile was totally disintegrated in this area. There was insulation wicking the water all over the place. Without the insulation the leak probably would have just gone down the hole in the slab for the drain. For reference, the house was built in 1977, slab on grade in north Florida.



I pulled the handle off to get a better look. The bottom adjustment piece is where it is leaking from. What does this thing do? I'll need to get a special wrench to open it I guess. My sockets don't fit with the tile there.


  • Nice job on the ball valves. If you leave them in place at the end of this job you will need to provide access to them, like with an access panel or door of some sort. Commented Feb 3, 2017 at 17:38

2 Answers 2


If you have drywall in the shower that has failed due to the moisture you need to replace it. If the corner is wet and failed you will likely need to replace the adjacent wall too.

At the very least with access in the back you are looking at installing a new valve. You can troubleshoot yours but for $30 you can get a builder's grade (what you have) or $100 you can get a nice shower/tub valve. This needs to be swapped out and the connections.

After you swap valve I would leave that open for a while. You can inspect the wall and make sure it dried out and you don't have mold growing. Just know that there is a pretty high chance of this wall failing but really no need to do it now as you should be able to install new valve without hurting it.

Note: If you do not want to retile now I would suggest using pex/sharkbite as you can just take them off to install new boards. I would definitely not weld your copper to valve unless you are doing tile at the same time.

  • Thanks for the advice. We are planning to redo that tub and tile in the near future so I'd hate to buy and install a new valve with handles, etc. For something we aren't even keeping. Especially if this can be fixed with a 50 cent washer or something like that. I just need a bandaid. I'll update my post with new details now. Commented Feb 1, 2017 at 1:59
  • See my note - I am saying make sure you can remove everything unless you redo tile. You should be able to have new stuff, take it off and do tile later without major isseus.
    – DMoore
    Commented Feb 1, 2017 at 3:34
  • Sorry, I wasn't clear. The wife will not allow the old two handle style in the new shower. So I'll need to completely redo it anyways. Commented Feb 1, 2017 at 3:45
  • If it is your valve itself that is leaking then in my opinion it is not worth troubleshooting. If you are planning on redoing the tile and have all of that water damage... just get it done.
    – DMoore
    Commented Feb 1, 2017 at 4:00

Your tub valves are equipped with integral stops. The slot you are looking at is a valve stem that can be turned with a slotted screwdriver, to independently turn off the water supply to the hot & cold tub valves, to facilitate easy repair.

Integral stop units are often installed (by conscientious plumbers) in apartments or condominiums so that tub/shower valves can be serviced in the future without interrupting water service to other units. They are also found in homes when commercial plumbers have some left over and use them.

If the stop valve itself is leaking (make sure it is not the tub valve proper, what you are seeing could be water dripping down from above) you will need to repair it. They are manufacturer specific, so see if you can identify the brand, I can't tell by the handle. Parts for it will not be easy to find, but it may just need repacking. Packing can often be repaired by leaving the existing packing washer in place and adding some additional packing material to it (look for "graphite packing string", "twist packing string" or some such). Or remove the valve stem and packing assembly and take it to a plumbing shop (not a "big-box"). It looks like a regular deep plumber's socket should be able to remove the hex-shaped valve packing bonnet.

enter image description here

This illustration is for a single-handle valve unit, but you get the picture

  • 1
    Heck, if you can't fix it you already have the wall open, and you know how to solder. Just replace the whole unit. Nice job on the ball valves by the way. Before you close up the wall you might try to attach that tub spout elbow to a block of wood attached across the stud bay, it was designed for that. It's to prevent twisting the pipes when you have to replace the tub spout. Commented Feb 1, 2017 at 6:07
  • Are these integral stop valves ball valves with a 90 deg turn or are they another type--gate type or washer type? Are you satisfied that the OP has established that the leak is from the stop valve and not from above it? Commented Feb 1, 2017 at 21:21
  • @Jim Stewart, the common integral stops I have dealt with are of the "plug" style (not gate, not ball), however there are probably many types; it is likely irrelevant because the leak the OP describes is not the valve "leaking by", it's leaking into the wall which (potentially) points to a packing gland leak. When you ask "are you satisfied that the OP..." the answer is no, that's why my answer advised the OP to positively identify the leak source as a prerequisite to the repair effort. Commented Feb 2, 2017 at 6:22
  • So to close these stop valves one turns the screw CW until it meets firm resistance? Presumably these stop valves are designed with the idea that they will be used very infrequently, right? Do they have packing or a sleeve that can be changed? Commented Feb 2, 2017 at 12:53
  • @JimmyFix-it Thanks for the information as to what those things are, that makes a lot of sense. I'll have to turn the water back on and see exactly where it is leaking now that I have the handle off and can potentially see more from the front. If it is the actual valve and not the stop valve that is leaking, is that better or worse from an easy fix standpoint? If this gets to time consuming I'll just leave it turned off for a few months until we are ready to re-do the shower. Commented Feb 2, 2017 at 13:47

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