DI water is used throughout electronics manufacturing. In semiconductor manufacturing it is used for multiple processes including the cleaning and etching of wafers. DI water is also used in other critical semiconductor processes such as CMP and immersion lithography. Over one thousand gallons of water is needed to process a single 300mm wafer. Because DI water is used pervasively and because it directly contacts the wafer, controlling its contaminants is critical to maintaining high yields in the semiconductor industry. Online monitoring of particle levels is a standard method of controlling contamination in DI water systems.