This summer I hit a gas line on a residential install. The gas company mark was between 6 20' off in places!!! The gas company made it into a major production, came out with 3 trucks, 8 men, backhoes and the works!!! They said that it would have cost me $1,500 except the mark was so obviously done wrong. The gas line was less than 3" in places on the yard to boot. It took them less than 5 minutes to install the repair, sounded more like an excessive penalty/fine than the price of a repair to me. So a friend of mine in the pool business gave me a tip which I want to share. Keep a bunch of PVC slip x slip ball valves on the truck and have some big vice grips. When you hit or nick a line, pinch it off, put a clean cut with your cutters and glue on the ball valve (work on the supply side). When the valve is dry, undo the kink and cut the discharge side and glue it together.