There are several different types of water filter systems available ranging from a simple carafe type filter to a permanently installed whole house filter. Each type has its advantages and disadvantages.
A pitcher or carafe type filter is the simplest and least expensive home water filter. The pitcher can sit on a countertop or in the refrigerator. To filter water, simply pour tap water into the top of the pitcher. The water flows through a filter into the pitcher below. These do not need any installation at all.
A little bit more sophisticated is a faucet mounted filter. These water filters thread onto the faucet in place of the aerator and have a filter cartridge that needs periodic replacement. Most faucet mounted filters have a lever that allows the user to switch between filtered water and unfiltered water to extend the life of the filter cartridge. A faucet mounted filter is a little more expensive than the pitcher type filter. Installation of these types of water filters is easy.
An undersink filter uses a much larger filter cartridge than a faucet mounted filter and is mounted permanently under the sink. These units filter all of the water going to the faucet and generally last somewhat longer than the faucet mounted filters. Installation of an undersink filter is a little more challenging than a faucet mounted filter.
Finally, a whole house filter uses an even larger filter cartridge, and sometimes uses a series of two or three cartridges to filter all of the water entering the house. These are permanently installed near the location where the water service enters the home and should be installed by an experienced plumber. These are the most expensive option, but do the best job of filtering water.
