Feel confident with every sip that you are providing the best quality water for you and your family. The KOHLER Aquifer reverse osmosis (RO) water filtration system effectively reduces contaminants including arsenic, fluoride, TDS, bacteria, virus, lead, mercury, chlorine, and pharmaceuticals in your cold water. This reverse osmosis membrane reduces arsenic, fluoride, lead, TDS, bacteria, virus, and more as part of the Aquifer reverse osmosis four-stage filtration system.