Filtration systems are used in both home and commercial applications, to purify the water. Commercial filtration usually begins by adding a coagulant to the water, waiting for settling, floatation or other sorting to occur, then passing the water through a filter. This filter might use rapid sand, slow sand, diatomaceous earth, or a membrane. The more impermeable the filtering substance, the smaller the particles it can remove. Some filters work well on a particular substance; for example, green sand can remove excess iron. In homes, the most common systems are granular activated carbon filters, and membrane filters. The activated carbon stops most contaminants, with the exception of microorganisms. It also removes chlorine, lead and certain inorganic chemicals, improving taste. Other home filtration systems use membrane filters, which screen out particles by forcing water through extremely tiny openings. One popular type of membrane filter is the reverse osmosis unit; others may utilize microfiltration, ultrafiltration, or electrodialysis. Overall, filtration systems can be a very effective way to get safer, better-tasting water. For more information on these systems, contact a water conditioning company.