The electro-optic liquid level sensing system detects a level of liquid in a container having an upper opening, such as for a server container of a beverage maker for a transport system, such as for aircraft, trains, trucks, buses and the like. A support housing mates with the upper opening of the container, and a primary liquid level sensor is mounted in the support housing for non-intrusively measuring the liquid level. A secondary liquid level sensor may be mounted in the support housing to sense a predetermined liquid level to prevent accidental overflows. Protective lenses may be placed in front of the primary liquid level sensor.