Originally Posted by nealtw
Do you have plumbing embedded the the concrete slab anywhere near or in the wall above the void in the fill below.
I was initially convinced that my void must have been related to this leak, but I can't find any evidence that plumbing runs under the concrete slab where the void has formed. I also looked into the void on a dry day and the soil in there doesn't look particularly moist.
The room over the void has plumbing in the wall (you can see the hose bib in one of the pictures) that runs to the adjacent room, which is a bathroom...but I cut into the wall and the pipes look totally fine in there. No sign of water. The bathroom is where the pipes run under the floor in the ~10" 'crawl' space. I am struggling to find how the pipes get from the bathroom to the water heater, which is why i have been creating so many holes...
I was really hoping there was some test I could do to make 100% sure it's in the hot water plumbing rather than the floor heating system.
Either way, it's soooo frustrating that I can't find any evidence of water anywhere. The meter reading tells me it's about 30 gallons/day leak.