Systems, methods, and computer program products for monitoring a level of product in a reservoir of a chemical dispensing system. A lid configured to engage an opening of a container includes a level sensor having a transceiver that transmits an output signal and receives a portion of the output signal reflected back to the transceiver. The level sensor determines an amount of the product in the container by comparing a characteristic of the reflected signal, such as time the reflected signal was received, to the characteristic of the output signal, such as the time the output signal was transmitted. The level sensor may also determine the size of the container based on the reflected signal, and take this size into account when determining the amount of product in the container. The level sensor transmits product level data to a mobile device in response to receiving an interrogation signal therefrom.