The purpose of a UV Purification System is to eliminate bacteria and other microorganisms from your water.  UV lights are or customers with a bacteriological issue, or customers who want the peace of mind knowing they are protected from any potential pathogens in their water.  The system is installed at the point-of-entry so bacteria is remediated for all household use!  The bulb should be replaced once a year because it loses intensity over time and for optimum results, proper maintenance and service is required.