What is the minimum depth for a water line into house?

The Minimum is 2 ft. Some places you can put a line in that is only 48 inches under ground. It all depends on what state your in... and the town or city. Up north where it gets cold the put main water lines in that are 8 foot under the ground or better. The reason being is because you gotta put the line below the frost line so it doesn't freeze. The deeper the line is... the better the chances are that you aren't gonna have problems...