A leak detection system for the rapid and accurate detection of the mean surface level change of a body of liquid is provided. The system is capable of sensing mean surface level changes under static or turbulent surface conditions. In one embodiment, the system includes a rigid walled sensor pod with at least one inner pod cavity that is so positioned to receive liquid from a body of liquid by way of an opening below the surface of the liquid such that dynamic equilibrium is possible and maintained between the mean surface level of the body of liquid and the amount of liquid in the inner cavity. The system further includes a sensor assembly having a stiction free float operating in conjunction with a strain gauge, and microprocessors applying algorithms to process, display, and report the sensor data in accordance with the needs of the end user or to initiate actions for automated control functions.