Step One: Locate the leak. Look for evidence of water damage, such as wet surfaces or mud on the floor. If you cannot see the leak, use a detector to listen for dripping or gurgling. Step Two: Excavate around the area of suspected leak. Use a rotary tool to create a hole in the ground large enough to fit a snake or digger. Step Three: Connect a trenching rod to the end of your excavator's bucket and use it to dig down towards the pipe. Once you have reached the pipe, cut into it with a sawzall or chisel so that you can access the damaged area inside the pipe. Step Four: Use a cup plunger to pump water out of the pipe while you repair it with loctite or epoxy. Apply several coats of sealant to ensure that the repairs are permanent. Step Five: Mix some extra epoxy in a small container and put it in your toolbox in case