Point-Of-Entry (POE) Filtration:
Point-of-entry (POE) filtration, otherwise known as whole house filtration, is when your water filtration system is installed right where city water or well water enters your home. Whole house water filters filter every drop of water that enters your home before it goes to any appliances or fixtures.
Point-of-entry filtration is generally limited to the removal of sediment to protect your appliances, such as water heaters, boilers, iron filters, water softeners, and fixtures, from built up sediment or damage which may be caused by the particulate. Because the entire home is supplied with filtered water, there is no risk of mixing up filtered and unfiltered sources to your fixtures. Common sediment cartridges are Spun Poly, Pleated Polyester, and String wound ranging from 5 to 50-micron ratings.
POE filters are commonly upgraded from 10” housings to larger housings, either a 20” double length or a 10” giant filter housings. A 20” giant housing may be required depending on the desired gallons per minute (GPM) of water flow to adequately supply all the faucets & appliances.
When taste and odor is a widespread problem at all faucets including the showers and bathroom sinks, the installation of a second POE filter plumbed in series with a carbon type, taste and odor cartridge, can remove the problem throughout the home. These include Carbon Briquette, Carbon Block, Granular Activated Carbon, and Powder Activated Carbon Wrap type cartridges. Having the sediment pre-filter will increase the life of the carbon filter cartridge ensuring it does not clog with particulate causing undesirable pressure loss prior to a 6-month period. The carbon cartridge is only to remove the undesirable taste and odors. Ideally the taste and odor cartridge will last 4-6 months before requiring change out, however this depends entirely upon how much the carbon absorbs out of the water.
Point-Of-Use (POU) Filtration:
Point-of-use filtration means the water filter is installed to provide filtered water a specific faucet in a kitchen or bathroom. Typically these are 10” standard filter housings. POU filters are sometimes installed in the cabinet underneath the sink. However, under the sink is not an ideal location (see information below on POU filter location).
These point-of-use system filters are typically furnished with activated carbon filter cartridges that address taste and odor issues. These include Carbon Briquette, Carbon Block, Granular Activated Carbon, and Powder Activated Carbon Wrap type cartridges.
Carbon filter cartridges can remove small amounts of sediment, but they are not designed to remove all sediment. The benefit to a point-of-use filtration system is that it is more cost effective to only filter the water through carbon filters to drinking water faucets where taste and odor is of concern. Activated carbon filter cartridges, are significantly higher in cost. Unnecessary filtration of any water that does not need improved taste and odor such as the water that supplies the shower, toilet, or outside faucets should be avoided.
Location for Point-Of-Use (POU) Filtration
Under the sink installation of point-of-use filters is not ideal for several reasons including but not limited to:
- Exposure to household chemicals and solvents such as aerosol sprays, cleaning products, and insecticides which may be stored in the cabinets below sinks can have an adverse effect on the plastic components of the filter housing.
- Due to the limited space, they are more difficult to service. It is hard to tighten and loosen the filter bowl in these hard-to-reach locations.
- Water damage. It is common to have some spillage when changing out filter cartridges. In addition, if something does go wrong resulting in a leak from the plumbing to and from the filter unit or the filter itself, having these filters installed on the second or third floor of the home can result in property damage.
It is not always possible to avoid an under the sink installation, however whenever possible we advise to install POU filters in a more appropriate location. They should be installed where a leak or spill will not result in property damage. This is ideally in the basement utility room with an adequate drain and directly below or as close to the kitchen or bath faucets as possible. Then a supply line should be run from the POU filter directly to the desired faucet(s). If this is not possible ensure that no harmful chemicals or solvents are stored near the filter and make sure to make routine inspections to make sure there is no leakage.
Additional Resources
https://support.boshart.com/how-to-replace-a-whole-house-water-filter-cartridge