Non-contact ultrasonic liquid level sensors use transducers and high-frequency sound waves to monitor liquid levels in storage containers. The sensor emits a sound wave, the signal bounces off the liquid's surface, and a transducer registers a time interval of the reflecting sound wave. The sensor uses the time interval captured by the transducer to calculate the liquid level. These are continuous sensors that measure constantly changing liquid levels of a container within a setpoint. Non-contact sensors are not immersed in the measured liquid but are mounted to the outside of a storage container, This makes them suited for monitoring corrosive liquids, wastewater, and bulk storage containers.