Abstract: This invention provides a method for detecting loss by leakage of liquid from a liquid-containing vessel by employing a submersible diaphragm-type pressure transducer having an integral operational amplifier in an appropriate electrical connection with a suitable power supply and digital volt meter. The method comprises steps of placing the transducer into the vessel beneath the surface of the liquid, energizing the operational amplifier to obtain an initial electrical output, recording the initial electrical output with a digital volt meter, adjusting the liquid volume of the vessel by a predetermined amount, (i.e.