Potential Leak - Driving Me Nuts

[Amkey]

Hi all,
I'm in dire need of some help here. I suspect some moisture build up around an upstairs bathroom because of mold in the vanity cabinets and extremely musty smell inside the interior wall directly behind the shower. A plumber told me that a leak would be obvious with wet spots on walls, floors, etc and told me he didn't think cutting into the walls was necessary at this time. So since I didn't like that answer, I tested myself. I turned off everything in the house at the source that I could (I don't have bath or shower access valves) and marked the meter. After 5 hours my meter swipe arm ticked three spots. My low flow meter is not indicating anything. After that I shut the water off at the main to the house, and 4 hours later nothing moved on the meter at all. The swipe arm didn't tick a bit. I did this same test last week and the arm moved 6 ticks after about 7 hours and that is why I called the plumber to begin with.

Does anyone have any other idea besides an extremely small leak that would make the meter move and move slowly at that? Again, I turned everything off that I could at the source and before then I did they dye test on all toilets and checked all sinks and valves for drips or moisture and nothing.

Thanks in advance for any help.

 

[Mr_David]

From what you have described you have a leak.
I pressure tested a few systems in the past and the test held tight.
Opened the wall and found a very small drip from a solder joint.
A very small drip may not even register on the flow meter but it sure as heck will cause water damage.

You need to open the wall and fix it.

Now that you have visible mold you should have it tested and professional people open the wall. Just like mushrooms, there are severely dangerous types of mold and should be treated properly.

 

[frodo]

Mr David is correct in his assumption, there is one other thing you can check on

around the valve face plate, handles, and tub spout,,,lets not forget the shower head

are these areas caulked ? are they sealed.?

water can run down the wall while showering and drip behind these openings

also....the waste and overflow trip lever. it has a rubr gasget behind the face plate..if it is not tight against the back of the tub

water from the spout will go into the wall..

 

[johnlewismcleod]

The water meter is useless for detecting small leaks. It is an open connection to the city supply and the supply pressure fluctuates throughout the day...thus the meter moves forward and back throughout the day.

A large leak will show, but not a small leak.

What you need to do is a static pressure test if you want to know whether or not you have a domestic water leak, but as your first plumber told you it's unlikely that you have a dom. water leak at all. Domestic water leaks drip 24/7 and almost always show evidence quickly once they start.

What may be happening is a drain leak or a leak on the shower head riser. These type leaks only leak when water is being used and can be sneaky and cause mold and smells before you know that they are happening.

You should call another plumber to help with this...or open the wall yourself and look.

 

[SHEPLMBR]

Could be a drain leak. Also something to consider that most people don't is the roof collar on your vent on the roof. Water can penetrate and run down all kinds of lengths of pipe. I had one that ran the length all the way to the basement once.