Well-water filters are filters which treat well water before it reaches the tap, removing impurities, sediment, and pathogens. Use of a filter on well water is designed to ensure that the water is pure and safe to drink, and to improve the flavor of the water. Home supply stores sometimes sell well water filters, as do plumbing suppliers, and they can also be ordered directly through specialty companies.
When people use an artesian well as a source of water, their water is generally safe to drink, since it comes from an impermeable pocket under the Earth's crust, making impurities unlikely. Wells in permeable areas of the water table, however, are subject to contamination from runoff, septic leach fields, and a variety of other sources. Well-water filters can remove many of the potential contaminants from the water, rendering it safe to drink.
In addition to removing some bacteria and viruses, a well-water filter can also trap sediment, which can make water look unsightly, in addition to adding a bad taste. Sand, rust, and dirt can all get into well water, filling it with sediments which are not necessarily harmful, but are potentially unpleasant to drink. Sediment filtration is also good for the plumbing, as it reduces buildups and blockages caused by sediment, and eliminates sediment staining of sinks, toilets, showers, and clothing.
It is possible to install well-water filters in several different locations. Some people install them directly at the pump, filtering the water as soon as it is brought to the surface. Well-water filters can also be placed at the inlet to the home, filtering drinking water while leaving irrigation water untouched. People may also choose to selectively filter individual taps, as for instance in the case of concerns about bacteria in the water which could cause sickness if the water was left unfiltered.
Before installing well-water filters, it is a good idea to test the water to see whether or not it needs to be filtered, and if so, for what. Some public health departments offer free well water testing, in the interest of public safety, while in other cases, it may be necessary to send a sample to a lab for testing. Once the water has been tested, the resulting list of contaminants and sediments can be used when shopping for a well-water filter. For example, if rust is a concern, seeking out a well-water filter which advertises rust filtration is important. Periodic retesting of filtered water is also recommended, to monitor the effectiveness of the filter.