Abstract: A system and method is disclosed for treating water to remove suspended solids, disinfect for bacteria and viruses and remove color, taste and odor to produce a potable water. A bactericide is introduced which is relatively stable and long term. The system and method introduces the bactericide to the water in an amount sufficient to kill the bacteria and inactivate viruses, The bactericide is maintained in the water at least for a time period sufficient to kill the bacteria in the water, and, until the water is desired to be consumed at which time the water may be passed through an ion exchange. In this way, there is a decreased likelihood that the water will become recontaminated with the same bacteria and/or viruses before the water is desired to be used. In one embodiment, the bactericide comprises metal ions, such as silver ions and/or copper and zinc ions.