This non-contact liquid-level switch uses sophisticated design techniques to guarantee that it functions reliably and precisely monitors level of solutions in many diverse industrial applications. Without making physical contact with the solution, its use obviates dangers of contamination and wear and tear which are inevitable in traditional level sensors, yet it is still capable of obtaining more accurate data than ever before. The switch has three primary functions: detecting the presence or absence of liquid; turning equipment on or off according to fluid level changes, and if there are abnormal levels that occur it will sound an alarm. Technological advances include state-of the art radar, ultrasonic, or optical sensors which permit it to operate on all kinds of liquids at widely varying temperatures. This switch is particularly suitable for the chemical, pharmaceutical, and the food and beverage industries where clean conditions are crucial.