I appreciate any advice on how to fix a leak from under my bathroom shower floor.

Water was flowing from the baseboards of the walls (about 1 liter), causing them to bulge and become disfigured, but I shut off the main supply valve upon seeing this.

With the main supply on, the leak is aggravated when I turn on the boiler cold inlet valve and the shower floor tiling gets hot over time as the boiler heats the water--which leads me to believe that the hot line is leaking somewhere beneath the bathroom shower floor.

There is also noise of running water coming from the other side of the wall in the dining room, where a sink used to be--I cut a hole in the wall here but did not see much leaking going on, but then again I couldn't see the base of the floor due to the cramped location.

If I turn off the boiler's cold water valve, then the noise and leaking almost stops entirely, but I now hear running water from the boiler's cold supply line, despite the valve being shut off.

Adjacent to the bathroom wall on the other side is the dining room sink, where the noise of the leak can be heard--I tried to cut the wall and peek but could not locate the leak.

Update: Today, I cut into the wall a bit more and I found that there are three connections going down into the ground from the hot side.

When I turn on the cold water inlet valve of the boiler, I can feel the middle pipe vibrate compared to the other two. I'm thinking this is the line to repipe... Any thoughts??

Thank you for any help!

Cheers, Edmund

  • What do you have underneath the shower? Crawlspace? Concrete slab? Another room?
    – brhans
    Nov 28, 2016 at 19:17
  • Hi brhans, I believe it is a concrete slab. Nov 29, 2016 at 4:23

1 Answer 1


RESOLVED: I discovered that the middle pipe was leaking where it met the slab, so I cut it, put a stop, and voila! No leak :) Thank you for all the help everyone!!

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Here's a brief video I made summarizing the problem and solution: https://www.youtube.com/watch?v=7UEjCwygSKo

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