Primo 5 gallon bottled water is purified to give you peace of mind, with minerals added for great tasting water. Big on safety. Big on health. Big on taste. Primo 5 gallon water undergoes a stringent purification process which includes sediment and carbon filtration, reverse osmosis, ozonation, and ultraviolet sterilization which, together, help to remove or reduce potential contaminants, deliver great taste, and ensure high-quality water for your safety. In order to reduce waste, Primo sanitizes and reuses empty bottles.