Pump and tank assembly of a system for washing the glass surfaces of a motor vehicle

The assembly (1) has a washing liquid tank propelled by an electrically operated pump (3) e.g. piston pump. A charge tank (7) directly communicates with an inlet orifice (5) of the pump and contains a washing liquid reserve. The charge tank has a connection end (8) separably connected to a sealed main washing liquid tank (9) i.e. removable flexible pouch. The pump and the charge tank are joined together in a single rigid block placed in an inlet of the pump. The charge tank provides a reserve for a stored quantity of a washing liquid corresponding to a quantity required for efficient washing.