Here is a strange one for you:
1) Evidence of a subfloor leak (warping and lifting of floor, telltale on water meter spinning)
2) Competent leak detection service pinpoints leak — says it is within 2′ of mark
3) Jackhammer up the floor, and find nothing but dry sand
4) telltale on meter has now stopped cold.
5) ????
Replies
Was your neighbor filling his pool?
Gremlins.
(Note that, in addition to leaks that come and go -- rare but not unheard of -- you could have a leak elsewhere, beyond some control valve, that follows the water line back to the point where the water was showing up.)
3) Jackhammer up the floor, and find nothing but dry sand
4) telltale on meter has now stopped cold.
5) ????
Plumbing detectives need more clues. Did you find the water line? What material is it? Is there water pressure near the suspected break point in the water line?
Found the line and the manifold for that part of the residence. The lines are all copper. Water pressure is +- 40 -50 psi.
Sometimes copper lines will seal themselves with corrosion over time if it's a small leak. Go over all the lines good on all sides and see if there might be evidence of that.
Don K.
EJG Homes Renovations - New Construction - Rentals
Here's a wild guess. Is there a pressure regulator on the line? Any chance that it malfunctioned for a while, then returned to normal operation?
I'm thinking that the leak may be pressure related, a pin hole that only shows up under higher pressure. I've seen badly cast copper fittings with pin holes. Had one of them open up and cause a bunch of problems once.
My neighbors water line crosses my property. I find that tempting . Is your neighbor handy like me?