1. I live on a three acre plot and there's no way that neighbors could be stealing water. No construction in the area either, and I haven't done anything lately involving digging. 2. Turning off the main valve stops the flow. 3. I can hear water hissing as the main valve is turned off. 4. The main valve is next to the street, about a hundred feet from my house. 5. I don't have an underground sprinkler system. 6. I've turned off everything possible inside the house (toilets), and the water still runs. 7. The water meter is mechanical, not electronic. I can't vouce for its accuracy, but I know that water is coming into the system. 8. I did find one toilet with a silent leak. It drained about half the tank in an hour. It's something to definitely fix, but not the cause of the major leak that I have. 9. The fact that the leak stopped for several hours has made me question my own sanity, but I know it did.
Yesterday, I went home early once again to attempt to find the shutoff valve next to the house. I went to the outside faucet where I believe the water line enters the house. I could hear water hissing as I got close to the faucet. I called my plumber and he's supposed to come by this morning and check it out. Hopefully, he can determine something.
I also dug down by the footing of the house under the faucet where I heard the hissing, but didn't find a water line. It must enter the house at a different spot. The faucet is located on the north side, so the line must enter at the northeast corner since that's the direction the main line points to from the meter. Naturally, there's a large shrub bed at that corner to inhibit digging. I'll let the plumber's younger crew do the digging. Hopefully, the leak will be found outside the house since it's built on a slab. I just hope it doesn't require tearing into the slab to try to determine where the leak is.
You would think a 4000 gallon per day leak would be easy to find, but I haven't seen any evidence of it yet. There are damp areas on the north side of the house, but we had a good rain a few days ago and that area is in shade, so it's not surprising that it is damp.
Thanks for the suggestions.
David Alexander Camden, AR