The present invention is a system for the determination of the useful life of a lubricant and detection of water or process fluid contamination level contained in a mechanical system. The system includes a lubricant sensor to measure a physical or chemical property of the lubricant, a database, a computer having access to the database, and a data acquisition system for providing power to the sensor and converting the measurement to numerical values for data storage. In a preferred embodiment the physical or chemical property is the dielectric constant.