We have a leak between the street and the house (about 400 ft). We don't know where the pipes enter the house but have narrowed the search to about 100Ft. Is there an effective way of finding this other than digging and if not, how deep do we have to dig for water in a concrete slab?

About 15 - 20 years ago, I a day off and the City was installing a sewer system and running water mains down the middle of the street and from the main line in the street to where each home would connect to the sewer line. I saw a worker walking with a device in his hand that lookedl ike he was looking for water beneath the earth's surface attempting to locate an existing water line. The device was either a piece of a metal clothes hanger or a wooden fork and he said that when he crossed the water line, the stick or hanger would suddenly be pulled downward and that indicated there was a wate line beneath. I said "got to be kidding, with all the other methods that must be available, that would be the least reliable. All the workers laughed and said that method worked. I though it was an old tale that had been handed down for years but I guess it's a good method ? Anyone, have any other experiences with looking for water lines similar to this ?

What the bondman's referring to is called "dowsing " and is not part of a plumbers tool kit. A much better way, if the pipe is galvanized, is to call around and locate a metal detector. Now you will be able to follow the service line all the way from meter to house. Good luck, Tom