CM wrote:

Thanks for all your responses. We went back over there yesterday and
checked
the water meter. The dial was spinning even after we made sure
everything
was shut off. Then we shut off the supply valve to the water heater and
the
water meter quit spinning. We left the valve off for a while and when
we did
turn it on there was hot water. This tells me there is an under slab
leak in
the hot water pipe.

We used an inferred thermometer to test the temperature of the floor
near
the kitchen sink and in the bath rooms while the water heater had
pressure
and when it did not have any pressure to see if there was any
difference
and found none. This was done over a few hours, but still no
temperature
difference in the floor.

Any hints on finding under slab leaks?


Here's a link to message board thread where a problem like yours is
discussed:

http://do-it-yourself.tribe.net/thre...f-652b6e4fa945

Good luck.