Which one is better: Carbon Filter or Reverse Osmosis Filter?

Should you buy a reverse-osmosis water filter or an activated carbon filter for your drinking and cooking needs? It is important to under stand the mechanism by with these two filters operate to make an informed decision.

Water purification is the process of removing undesirable chemicals, materials, and biological contaminants from contaminated water. The goal is to produce water fit for a specific purpose. Most water is purified for human consumption (drinking water).

In general the methods used include physical processes such as filtration and sedimentation, biological processes such as slow sand filters or activated sludge, chemical processes such as flocculation and chlorination and the use of electromagnetic radiation such as ultraviolet light.

According to a 2007 World Health Organization report, 1.1 billion people lack access to an improved drinking water supply, 88% of the 4 billion annual cases of diarrheal disease are attributed to unsafe water and inadequate sanitation and hygiene, and 1.8 million people die from diarrheal diseases each year. The WHO estimates that 94% of these diarrheal cases are preventable through modifications to the environment, including access to safe water.[1] Simple techniques for treating water at home, such as chlorination, filters, and solar disinfection, and storing it in safe containers could save a huge number of lives each year.[2] Reducing deaths from waterborne diseases is a major public health goal in developing countries.

Activated Carbon Water Filters Vs Reverse Osmosis Systems
By Tom Neuman

The need for proper Home Water Filtration Systems becomes apparent, since we have to face a disconcerting development: current water treatment facilities are timeworn and municipal city water sources contaminated with pollutants. Which water treatment solution / water filter system makes the most sense to ensure pure, clean and healthy water for the family? The examination of two common water filtration & purification methods throws light on this question.

Reverse Osmosis Water Systems Lack Efficiency

In a reverse osmosis system (ROS) the water is passed through a sediment filter to remove sediment, dirt and algae. In a next step, the water passes through one or two (depending on model) pre filters, which remove volatile organics from the water. In a next step the water reaches the reverse osmosis membrane, which removes minerals, lead, inorganic compounds, salt and more. The water then flows into a holding tank (4 gallon), which is an essential component to the system, since the process of reverse osmosis is not instantaneous.

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The small pores of the Reverse Osmosis membranes are restrictive to such organic compounds as salt and other natural minerals. That means reverse osmosis is very effective at desalinating water and producing mineral-free water for use in print- or photo shops. In terms of removing dangerous chemicals and purifying drinking water, the reverse osmosis alone, without an additional carbon filter, is not sufficient, because the pores of the membrane block only large molecules like salt.

Natural Trace Minerals will be Blocked

Only activated carbon filters are able remove the molecularly smaller substances and chemicals like pesticides, herbicides and chlorine. Another disadvantage of Reverse Osmosis Systems is the removal of naturally occurring and healthy minerals. Natural trace minerals will be blocked by the Reverse Osmosis membrane. These minerals make the water tasty and serve as a vital function to our body system.

Water without these trace minerals can actually be unhealthy for the body. Long-term consumption of such de-mineralized water can be harmful to the body system and result in mineral deficiencies in the body. The waste of a large portion of water running through a Reverse Osmosis System is also problematic. The system generally wastes two to three gallons of water for every gallon of purified water it produces

Activated Carbon Filters More Reliable

The process of water filtration with Activated Carbon Filters is characterized through the flow of water through a granular bed of sand or another suitable media (e.g. several stages of carbon and multimedia filters). The media retains most solid matter and ensures the removal of all unwanted materials while permitting the water to pass. The first filtration stage will remove the most concentrated chemicals like chlorine and Trihalomethanes; subsequent stages will remove smaller and more evasive chemicals, like herbicides or pesticides.

Carbon Adsorbs Chemicals

Granular Activated Carbon Filter Systems clear water of larger compound materials (e.g. salt) and retain trace minerals in it, and also selectively remove much smaller and more dangerous chemicals like chlorine and pesticides, which Reverse Osmosis Systems can’t remove. These water filters use a chemical adsorption process (which means to attach by attraction). In this way a variety of dissolved contaminants are attracted to and held on the surface of the carbon particles. Above that, these systems do not require a heat or pressure source, which makes them fairly cost-effective.

Pesticides, solvents and other volatile organic chemicals (VOCs) are not completely removed by Reverse Osmosis Systems because the pores of the membrane are blocking only larger molecules. Only if an additional post carbon filter is used, these filters are effective and able to remove the molecularly smaller substances and chemicals like pesticides, herbicides and chlorine.


Granular Activated Carbon Filters are effective and valuable water treatment devices, but the consumer has to consider its limitations. One has to keep the water pressure at a uniform and steady flow rate that needs to be maintained for optimal performance, and the filter cartridge must be changed according to the manufacturer’s recommendation and/or the number of gallons the filter is rated for.

The most effective Home Water Filtration and Purification System currently available on the market is a Point-of-Entry Water Filter System, which combines two filtration technologies: Granular Activated Carbon and KDF process media, where water runs through several layers of GAC and KDF media for maximum exposure and purification.

Waterfilter-Info.com wants to draw attention to an alarming endangerment: the contamination of drinking water. US scientists state that it is not longer safe to drink impure and unfiltered tap water. Waterfilter-Info compares different water purification systems and water treatment methods and delivers comprehensive information about which water filter systems are most reliable in terms of Contaminant Removal.

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