I called Sonic Leak Detection after getting a ridiculously high water bill from the City of Santa Fe which was 20 times my normal bill. The city came out and the meter was showing 2 gallons per minute even though no one was using any water in the house. There was absolutely no visible leak in the house nor on the 3 acre property and no toilets were running. Willie Honohan, the owner of Sonic, came to the house and pumped nitrogen through the water line and tested all around the property and in the house by using sophisticated electronic equipment. He located the leak which was the size of a small nail head in an old pipe 4 feet underground. He marked a spot a few inches from where the leak was found 4 feet down. No plumber could ever have found this leak because there was no sign of water anywhere and I did not want holes dug all over the property. The leak just kept going underground. The price for finding the leak was reasonable. I highly recommend Sonic Leak Detection