How to Fix a Shower Leak

Why is Shower/Tub Unit Only Leaking When Used as a Shower

By Mark J. Donovan

Question: Mark, we have a tub shower combination unit on the second floor, that when the shower is used it leaks like there is no tomorrow. It does not leak, however, when a bath is taken. Can you give us any ideas on what could be happening?

Answer: There is a copper pipe that rises above the mixing valve for the shower. One end of the copper pipe attaches into the mixing valve. At the other end of the pipe, the showerhead attaches. Most likely you have a shower leak somewhere in this path since you observe no leak when using the shower/bath unit for just a bath.

I would first try removing the showerhead pipe that protrudes out from the shower wall, and re-installing it with fresh plumbers tape wrapped around the threads at the end of the showerhead pipe.

If this does not solve your shower leak, you will need to open up the wall behind the shower area to get to the showerhead pipe and shower mixing valve. Once you do this, the location of the shower leak should become very obvious when you turn the shower on.

You can then re-sweat the joint (re-flow the solder) to eliminate the shower leak. Depending upon where the shower leak is occurring, you may need to first drain the water in the supply lines to the mixing valve to re-sweat the joint. If you are unfamiliar with, or unwilling to, re-sweat the joint then you will need to call a plumber to do this for you.

How to Fix a Shower Leak

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