Includes 2 pre-filters: the first sediment pre-filter removes sediment, rust, dirt, and other solid debris; the second carbon pre-filter removes chlorine, odor and protects the RO membrane which removes dissolved metals and salts, plus other harmful contaminants. A storage tank holds the RO processed high quality water until needed, in which case, the water will then pass through the final post-filter which removes tastes, odors and organic chemicals.