The point-of-use and point-of-entry systems addressed by this Standard are designed to be used for the reduction of specific substances that may be present in drinking water (public or private) considered to be microbiologically safe and of known quality. Systems covered under this Standard are intended to reduce substances that are at very low, yet measurable concentrations but not at definitive concentrations of known health concern. These substances may be soluble or particulate in nature but their presence, even at very low concentrations, may influence public acceptance/perception of the drinking water quality. The systems addressed by this Standard are not intended for reducing these specific substances at higher concentrations that may have a known acute or chronic health effect. It is recognized that a system may be effective in reducing one or more of the emerging compounds/incidental contaminants listed in this Standard. It is not necessary that a device be able to reduce all the Emerging Compounds/Incidental Contaminants listed in order to meet the requirements of this Standard. Systems with components or functions covered under other NSF or NSF/ANSI standards or criteria shall conform to the applicable requirements therein.