Abstract: A pump testing apparatus includes a tank mounted on a mobile trailer for testing water pumps associated with fire fighting equipment. Two rotatable draft tubes extend into the tank for drawing water from the lower part of the tank through suction hoses connected to the pump being tested. Two inlet manifolds receive water discharged from the pump being tested and direct the water into respective flow stations that measure the water flow rate. The water is then dispersed back into the tank. The tank has a system of baffles to prevent cavitation of the water circulating through the tank. A cooling system is provided to cool the water within the tank to maintain a desired water temperature during pump testing. The cooling system includes a supply line having a cool water inlet for connecting to a source of cool water, and cool water outlets at spaced locations throughout the tank.