Based on the age of the line and the damage, replace as much of the
line as possible.
As for replacement methods:
1. Dig, cut concrete & replace
a. Pipe spliting - 2 holes are dug, one on each end. the
plumber pulls a new pipe through the old spliting as it goes. Great
b. Pipe lining - A fiber glass like sock is blown into the
pipe, then a bladder is inflated inside the sock to force it against
the inside of the exisiting pipe. Let it cure, remove the bladder and
you are back in business.
Price: - In most cases you get what you pay for. Check references,
licenses, bonds, etc.