Abstract: A nozzle with self-contained high pressure booster pump is carried on a pistol grip handle with a small motor to drive the eccentrically-pump. A portion of the water from a conventional hose fitting flows laterally into a pump cylinder and then radially through the piston itself to exit axially through a check valve and into the pump chamber ahead of the piston. During the working stroke the water is driven out of the piston into a pressure chamber and then through a restricted passageway to exit in a jet stream. Another portion of the supply water is diverted around the pump cylinder to the same nozzle to flush away debris loosened by the jet stream.