Water pumps are mechanical or electromechanical devices that are designed to move water through pipes or hoses by creating a pressure differential. The two most common types of pumps used for pumping water are centrifugal pumps and positive displacement pumps. Centrifugal pumps, as their name implies, makes use of centrifugal force to take water that enters an impeller and uses the rotational energy generated from spinning that impeller to produce hydrodynamic energy.
Positive displacement pumps use a piston, plunger, diaphragm, or a rotating cog or gear to mechanically move a fixed volume of fluid repeatedly through the pump chamber. Positive displacement pumps can move water at the same speed notwithstanding the inlet pressure, which centrifugal pumps cannot do.