you can go rent a coolant system leak down tester which pressures you cooling system via a pump that attatches to the radiator......pump the system and listen for the leak. By the sounds of it , it sounds like your water pump took a dump on you. I would also do a compression check just to be sure you didnt blow a headgasket
The only water seal near the crank would be the waterpump to front cover gasket. It could always have been leaking somewhere higher and travelled down to that point as well. What was done to the engine recently besides the installation of the supercharger? Did you remove the intakes or heads recently, were new head gaskets installed? There are many possibilities and it would be helpful to know more about the engine in order to help diagnose.