On Sun, 11 Dec 2016 05:56:53 -0800 (PST), trader_4
wrote:

On Saturday, December 10, 2016 at 10:50:37 AM UTC-5, Dean Hoffman wrote:
On 12/10/16 7:06 AM, slate_leeper wrote:
I wrote a while back about an underground water leak. Well, I have
determined that the water leak is not in the feed line but is within
the structure. I was misled by a main shutoff valve that didn't
fully shut off.

So, back to the problem. I am using 120 gallons a day (5 gallons per
hour) in a house that is unoccupied. I have inspected everywhere.
There are no dripping faucets. All toilets have been shut off. There
is no visible moisture anywhere. This is a 70's "raised ranch" style
house with no crawl space. Once the water main enters from the
street, all piping is within the structure.

So where the heck is it leaking?

Could you use air to locate the leak? Shut the main off and
connect an air compressor as far upstream as possible. Set the
pressure regulator below the pressure rating of the pipes. The air
should eventually push the water out and maybe you'll be able to hear
the leak. Stethoscope?

+1

I used that method to find a leak in an underground pool line. I was
actually just going to use it to pressure test the line to see if it
was leaking, but when I hooked the compressor up, air came bubbling
up out of the ground where the leak was.

Like Ed said, 5 gals an hour is a lot of water to be leaking in a
structure. You would think it would have to be underground, or
someplace with a direct, hidden path to ground.

I find it interesting the OP has not, as of yet, responded in this
thread.