Your water may, or may not, suffer from any of these contaminants. If you're concerned about the quality of your water, have it tested by an independent laboratory. The filtration system you need for your home depends upon the quality of your water supply. Water filters do require some maintenance. Cartridges should be changed according to the manufacturer's recommendations.
Taste- and Odor-Causing Contaminants: If your water smells or tastes bad, there's little doubt that you would benefit from a water filter. Municipal water often smells of chlorine, which is used to treat the water. Well water, which is dependent upon many local conditions affecting the water supply, also may smell bad. Water filters often treat these conditions by using granular activated carbon (GAC), a substance that absorbs contaminants that would otherwise cause offensive tastes and odors.
Filters that use GAC may cause cloudy water for the first couple of weeks after a filter change. This is a harmless condition caused by the release of air from the GAC and can be reduced by running the water for several seconds before each use until the air is flushed out.
Rust and Sediment: You may notice visible particles in your water. For example, sediment can collect in the bottom of your dishwasher or commode. Larger particles may collect behind the screens of your faucet aerator. Smaller particles may collect at the bottom of a glass of water that sits for a time. Rust and sediment are easily collected by particulate filters. Whole-house particulate filters are easy to install. They not only protect your drinking water, but also appliances, such as dishwashers and ice makers.
Water filters aren't effective against clear water iron, which can leave red stains in tubs and toilets. To treat this substance, a water softener is required.
Bacteria / Parasites: If your house relies on a well, your water is more likely to be contaminated by bacteria and parasites. Many bacteria and parasites occur naturally in clear water supplies. Others are the result of water-supply contamination by sewage and wastes. Some bacteria and parasites affect the taste and smell of the water, but others don't. Cysts, such as Cryptosporidium and Giardia, are particularly hearty parasites and have been known to contaminate even chlorinated municipal water supplies. They can cause illness and are a serious hazard to the young, elderly or those with immune deficiencies. Water filters are available with various filter cartridges, which are effective against many of these contaminants.
Lead: Houses built before 1986 may have pipes joined with lead solder. Your municipal water system also may be composed of components that contain or are soldered with lead. If you're concerned about the possibility of lead in your water supply, have your water tested by an independent laboratory.
Lead contained in water is tasteless and odorless, but should be avoided as much as possible. It can be removed from your drinking and cooking water by installing a lead filter directly under the sink in your kitchen. This filter placement assures that even if you have lead in the pipes of your home, it'll be removed from your drinking water.