May want to make sure you have it or that the person you hire does. Fellow was doing the field for some friends of mine. He hit the well case, busted the pipe and sheared off the supply line. Dropped enough debris into the well to wedge the pump and broke the wire trying to pull it for repairs. Drilling a replacement well and at 500 feet they are only getting aprox <2 gallons a minute. This is a busy farm with many animals and that won"t do, they start drilling Monday on a second hole (third actually) Going to be pretty expensive, not to mention the bad will that these folks being out of water for a couple weeks has caused.