Home filtration units use activated carbon filters, which adsorb organic contaminants and constituents that cause taste and odor problems. Depending on their design, some units can remove chlorination by-products, some cleaning solvents, and pesticides. To maintain the effectiveness of these units, the carbon canisters must be replaced periodically. Activated carbon filters are not efficient in removing metals such as lead and copper. Because ion exchange units can be used to remove minerals from your water, particularly calcium and magnesium, they are sold for water softening.
Some ion exchange softening units remove radium and barium from water.
Ion exchange systems that employ activated alumina are used to remove fluoride and arsenate from water. These units must be regenerated periodically with salt. Reverse osmosis treatment units generally remove a more diverse list of contaminants than other systems. They can remove nitrates, sodium, other dissolved inorganics, and organic compounds. Distillation units boil water and condense the resulting steam to create distilled water.