I asked PlumbingPros for their best price on replacing a 4" corrugated drain pipe (about 120ft long). They quoted $4,200, told me they would use a trencher that would damage the lawn where they laid the new pipe and if they damaged any irrigation lines, it would be my responsibility to fix. I had a second company do an excellent job of replacing the old pipe by hand digging it and replacing with 4" pvc. Almost no damage to the lawn and no damage to the irrigation system. They charged $1,350.