Tool Tips: Empty a water heater quickly, prevent scratched tubs, lifting advice
For years, when replacing a defective water heater, I simply hooked a garden hose to the bottom drain valve and put a 3/4-by-1/4-inch bushing into the relief valve. Then, I hook my little diaphragm air compressor to it, hold open the relief valve, and in less than ten minutes, the tank is empty. It even leaves the garden hoses empty.