I have a slab one story house and the water bill doubled the last 2 months. The triangle on the water meter spins when no water is on indicating the doubling of the water bill is a leak. Put die in toilets to confirm it is not toilets. If I put my ear against the wall where the water main enter the house I can hear dripping but the floor does not appear to be wet. I'm told that since a lot of water is leaking and no water damage signs the leak has to be in the slab but the dripping sound only on that wall seams a big coincidence. Should I open the wall or pay $350 for special in slab leak detection?

Tear open the wall if you have the skills to reinstall drywall. You can buy or rent a small camera on a tub that can be inserted in the wall so might get away with a very small exploratory hole. Milwaukee Electric Tools 2310-21 M-Spector Digital Inspection Cameras (http://www.google.com/products/catalog?q=milwaukee+camera+tool&hl=en&prmd=imvns&resnum=1&bav=on.2,or.r_gc.r_pw.,cf.osb&biw=1675&bih=824&wrapid=tlif132433874574510&um=1&ie=UTF-8&tbm=shop&cid=16497371753621796606&sa=X&ei=Ts7vTq6fJMPi2gW6-JWlDw&ved=0CIMBEPMCMAA#) The person who told you its likely the slab is likely correct. Double water usage is a lot of dripping. Check the wall first because it can be done cheap;y but get 3 bids from plumbers who can locate and repair a slab leak.