Water systems that use water filtration methods such as carbon, carbon block, granular activated carbon, kinetic degradation fluxion (KDF), and particulate filtration produce filtered drinking water.
Water filtration is not the same as water purification, which uses methods such as distillation, reverse osmosis, and ultraviolet to disinfect water.
You can learn more about water purification methods here.
For daily, long-term use, we recommend filtered drinking water over purified water for many reasons.
You can read more about the many benefits of drinking filtered water here.
The following is a summary (in non-technical language) of the most common technologies used for water filtration.
Carbon filters are considered the most efficient and the most effective filters for removing the worst contaminants in municipal water.
This water filtration method utilizes a process called adsorption, which is where particles stick to the surface of the carbon material.
These filters are usually made of powdered block carbon or granular activated carbon (GAC). Activated carbon has a slight electro-positive charge to it. The negative ions of the contaminants are thus more attracted to the positive charge of the activated carbon.
Both types of carbon filters are effective, but there seems to be ongoing debate about which one is more effective.
Some of the water contaminants that carbon filters remove include chlorine, chloramines, trihalomethanes, radon, benzene, dissolved volatile organic chemicals (VOCs) such as herbicides and pesticides, as well as hundreds of other man-made chemicals found in our water supplies.
Carbon filters also remove bad tastes and odors and will reduce the amount of hydrogen sulfide as well as sediment in the water. However, carbon filters are not effective for removing heavy metals or some inorganic pollutants such as fluoride, arsenic, hexavalent chromium, and nitrate.
Carbon filters are cost effective but often require frequent filter changes and reduced water flow for optimum filtration.
The KDF filter uses a copper-zinc formulation and a chemical process known as oxidation reduction (or redox), which works by exchanging electrons with contaminants.
This water filtration method is often used in conjunction with other technologies for overall effectiveness of the water system.
The KDF method is especially effective when used in conjunction with multi-stage filters that also utilize carbon and particulate filtration.
One of the key benefits of KDF filters is that they remove heavy metals such as lead and mercury.
This is one of the reasons why they combine so well with carbon filters, since carbon filters are not effective at filtering heavy metals.
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KDF filters are also effective for removing chlorine, iron and hydrogen sulfide, as well as certain bacteria, viruses and fungi.
Particulate filters screen out large particles from water, such as sand, sediment, some bacteria and unhealthy microbes.
These filters are also called mechanical, or micro, filters and are often used in conjunction with other technologies.
Particulate filters are used most effectively as a pre-filter in a multi-stage, water-filtration system.
Ceramic filters are similar in that they have tiny holes throughout the filtration media that blocks solid contaminants such as sediment and cysts from passing through.
None of these filtration methods remove chemical contaminants and are not recommended as primary filtration methods.
This water filtration method involves passing water through an ion exchange unit in which hard metal ions are replaced by softer sodium ions.
Thus, the technology is effective for making the water feel softer and for preventing mineral deposits from collecting in plumbing and fixtures.
However, used alone this method is not adequate as a water filtration method for drinking water. It is often used in combination with reverse osmosis, carbon filtration and electrolysis water filters.