The Ultraviolet light bombards water-borne bacteria with high-intensity ultraviolet light. This light is strong enough to kill bacteria and render viruses inert passing through the canister without disturbing the healthy minerals present in your water. The light is low maintenance and just requires a yearly change to ensure proper light intensity for cleansing your water. The unit comes with a reminder alarm and an indicator to note when the light has gone out. This light mounts to the wall after any treatment systems that you already have.