POINT-OF-ENTRY (POE) SYSTEM
Point of entry systems, also called whole house systems are usually installed where the water enters the home, just after the water meter. Most homes have the water meter located in the basement or lower level, however in warmer climates water meters are often in the garage or outside the house. Water softeners are always POE systems. The most popular POE systems for the removal of chlorine and contaminants utilize KDF media and carbon. For microbiologically unsafe water, ozone, ultra violet, and Doulton Sterasyl are recommended.
POINT-OF-USE (POU) SYSTEMS
The majority of drinking waters systems are point of use (POU) systems, where purified water is delivered to either a kitchen faucet, to a dedicated auxiliary faucet installed at the kitchen sink, or through a filter that is incorporated into a drinking water bottle.
WATER BOTTLE FILTRATION SYSTEMS
Designed for personal use, these systems utilize a variety of technologies including activated carbon, ATS media (BASF), ceramic, Doulton Sterasyl, and ultra filtration technologies. Many of these systems can be used for microbiologically unsafe water, and are convenient for those who want to ensure that all the water consumed is free of chlorine, chemicals, contaminants, etc. Some have an integrated straw, while others have a push/pull cap. There are no portable water purifiers that remove fluoride.
Pour through designs rely on gravity, where water slowly drips through a filtration material into a pitcher or carafe. Small pitcher designs can be stored in a refrigerator, while large carafes, which often use Doulton Sterasyl filtration, can sit on a table or counter. Pour through designs have a small capacity, and require constant filling. They also have a lower filter capacity than most systems, however Doulton Sterasyl features a ceramic material that can be cleaned, extending the life of the system.
FAUCET MOUNT SYSTEMS
Popularized by Brita and Pur, this filter design is mounted directly on a sink faucet, usually in the kitchen or bathroom, replacing, or installed just before the aerator. There is usually a diverter that directs water to the filter, so the filter material is only utilized when drinking water is required.
MANUALLY FILLED COUNTER-TOP UNIT
Requiring manual filling and using a variety of filtration media including activated carbon, Doulton Sterasyl and steam distillation, usually placed on a counter, or near a sink to make it easy to fill with water.
COUNTER-TOP WITH FAUCET CONNECTION
Counter top units are usually placed either behind or next to a kitchen or bathroom sink, and connected by a diverter valve to the faucet. In some designs, treated water is dispensed from a spout that is part of the unit, while others divert the water directly to the faucet. Electric water ionizers are usually counter top units. Some units market under the counter kits which include accessories for under the sink installation.
Installed under the sink, or in some cases in the basement under the kitchen, plumbed in systems are connected to a cold water pipe using a saddle valve or permanent connection. Some designs produce water that is dispensed through the normal faucet, while others use a separate tap, usually mounted next to the sink by drilling an additional hole in the sink to the left or right of the faucet, or using a hole designed for a dish sprayer. Plumbed in systems are often not the ideal choice for apartment dwellers who may not be able to alter their sink or countertop, however there are chrome caps that can be used to cver the drilled hole in a stainless steel sink, and the saddle valve or water connection can be shut off to allow for proper removal.