DIY Frequently Asked Questions / Water Filter')">
Used to remove bacteria and/or chemicals suspended in water to improve its taste and smell. Filters either install under the sink or at the point where the water supply enters the building (whole-house filters). Others mount on the faucet or countertop.
The basic types of water filtration devices are activated-carbon filters, reverse osmosis, distillation and aeration.
Activated-carbon filters are the least expensive water filtration devices. They can remove impurities and improve water taste and odor, but do not eliminate dissolved minerals or bacteria. One solution is to combine a carbon filter with a chlorination system.
Reverse-osmosis systems take out dissolved lead, mercury,cadmium and other heavy metals that are present in the water, but will not eliminate microorganisms. They are also relatively expensive.
Distillation removes most impurities in the water system. Distillers work slowly and must be cleaned regularly.
Aeration reduces, but does not necessarily eliminate, the levels of iron, chlorine and other gases in the water. It works best when combined with other treatment forms.
Some filters feature cartridges that can be cleaned and reused several times before replacement.
Filters based on ceramic technology will remove up to 100 percent of bacteria as well as chemicals, tastes and odors. Some have proven effective in removing such contaminants as algae, chlorine and detergents found in many urban water supplies.
Another under-sink model even reduces levels of MTBE, a gasoline additive that contaminates some wells and municipal water systems.
Always study information about the specific filters that you are selling.