When the water bill for the vacant house showed 3800 gallons of water
for the month. I went over and shut off the line inside the house,
thinking that a toilet or something was leaking. Next month the bill
was about the same. So I looked at the meter, and sure enough the
rotating indicator was moving slowly even though the water was shut
off at the house.

Is there any way to locate an underground water leak in the line
from the road to the house other than by digging trenches?

My mother-in-laws water line broke underground a few years ago. By the time
we could drive there the running water had caused a small sink hole in the
yard. So finding her leak was fairly easy (fixing it was another matter).

You might check the yard for depressions or wet/soggy areas. That might
help you narrow it down. Of course, if the line is buried really deep it
may not show on the surface.

I suppose you could use a stethoscope or something to "listen" for running
water at various points in the yard. But if it's buried deep or a slow
trickle you may not be able to hear it.

If you've had a stretch of dry weather, you might be able to use a moisture
meter to search for any differences in the ground moisture. But that's
probably a long shot.

Unless you've had heavy vehicles driving on the yard, the most likely
failure spots are at the house end, or out at the meter. I would look there
first.

Unless you can easily find the leak, it would probably be smarter to
abandon the existing line and run a new water pipe. If you have a leak now,
you'll probably end up with more in the future. Have the underground
services marked, then rent a ditch witch to dig a new trench to the house.
You might also be able to use a vibratory plow to bury a new line without
having to dig a trench.

Good luck!

Anthony Watson
www.watsondiy.com
www.mountainsoftware.com