re: Locating a leak. Using 17,500 gallons a month.

I had a leak under the slab as well. It wasn’t enough to make a noticeable difference in my water bill (I think it was about 20 gallons per day) but I could hear a hissing sound coming from a wall near the pipe. No water anywhere but saw the meter indicator moving very slowly. Pipe was fixed by lining with PEX.