Even if the water has been fully purified, the risk of secondary pollution is high when it is in the pipeline or water tank for a long time. The ultraviolet mercury lamp has a large volume and is not easy to be used for local disinfection. In this regard, the common countermeasure is to discharge water regularly.

Deep UV LEDs are more compact than mercury lamps and are suitable for small spaces. It has the characteristics of low power consumption and long life. It is expected to be used in every place where water passes through, such as water dispensers, beverage vending machines, coffee machines, dental chairs, intelligent toilet seats and ice makers.