A hand lever actuated pump for testing a water line for leaks by pumping water into the line under pressure comprises a container for water to be pumped and a hand lever actuated piston and cylinder type pump having suction and discharge strokes in response to displacement of the hand lever in opposite directions about a lever axis. The piston and cylinder components of the pump are pivotally supported on the container and interconnected with the hand lever so as to provide a high flow rate during the initial part of the discharge stroke and a progressively increasing leverage for displacing the piston during the discharge stroke to provide high pressure discharge at the end of the discharge stroke with a low force application to the hand lever.