Abstract: A leak testing device capable of detecting and measuring gas and water leakage in valves and other parts of pressurized pneumatic and hydraulic systems is disclosed. Gas from a pressurized source is injected into the apparatus of the device and is adjusted to the desired pressure. The flow of pressurized gas is routed into either the gas test section or the water test section of the device. The test media is then routed through the proper range flow meter of the device and then through tubing into the apparatus or system to be tested for leakage. The amount of leakage will be equal to and can be measured by the reading on the flow meter instrumentation.