The present invention provides a water sensing system for sensing the water content of a liquid and communicating water content information to an operator. Communicating water content information may include processing the sensed water content value and comparing the value to one or more threshold values to qualify the sensed value. According to another aspect, the water sensor includes isolated 4-20 mA interface outputs for use with external devices such as programmable logic controllers. According to another aspect, the present invention provides a water sensing system which senses a relative water content value and converts the relative water content value to an absolute water content value. According to another aspect, the present invention includes methods and circuitry for calibrating a water sensing system. According to yet another aspect, the present invention provides a liquid purification system to sense the water content of a liquid and remove water from the liquid using a purifier.
