A drain system for a wet/dry vacuum, including: a generally U-shaped dolly having wheels mounted thereon for rotation; a collection drum having an inside bottom surface defining a plane, the collection drum adapted to be mounted to the dolly; a drain opening defined by the collection drum, the drain opening defines an inside lower surface, the inside lower surface generally in line with the plane defined by the inside bottom surface of the collection drum and the drain opening being positioned generally opposite the closed end of the U-shaped dolly; and a cap having first and second ends, the first end adapted to mate with the drain opening in a sealed manner, the second end defines a member adapted to extend out from the collection drum, the member has a length sufficient to prevent the collection drum from completely tipping over.