An employee was preparing to clean product transfer lines. The employee placed a hose with a connected stainless-steel wand into a 55-gallon drum used to rinse the lines and that he had just emptied of residual water. While lifting the drum into the vertical position, the main water valve lever/handle dropped to the fully open position. This caused an increase in flow and backpressure in the hose. The hose disconnected and the employee was sprayed with hot water (120 degrees F) on the right side, resulting in burns to their arm, shoulder, and back.