Carbon water filters are available in a range of effectiveness from 50 microns to 0.5 microns; the lower the amount of microns, the more effective the filtration is at removing volatile organic chemicals.

An average, under the counter, carbon water filtration system contains 12-24 ounces of activated charcoal; the charcoal will generally originate from one of three sources bituminous, wood or coconut shells.

The best carbon water filters are commonly known to contain coconut shell based carbon, because this carbon is known to be more effective the cost is often about one fifth more than wood or bituminous charcoal. Charcoal is able to remove impurities from water by absorbing the volatile organic chemicals, there by improving the taste and odor of the water.

Volatile organic chemicals are substances such as pesticides, herbicides, chlorine, benzene, trihalomethane compounds, radon, solvents, and man made chemicals which are found in at minimum trace amounts in most tap water. Carbon water filters are generally poor at removing metal substances from water like iron, however some may be able to; is the micron level of the carbon water filter is 0.5 it should be able to remove iron, manganese, and hydrogen sulfate.

If heavy metals are a problem in the tap water there will be better results by purchasing a filter specifically for those reasons as carbon water filters generally cannot completely remove heavy metals from the water. Carbon water filters also may not be able to remove inorganic contaminates such as arsenic, asbestos, barium, beryllium, chromium, copper, fluoride, mercury, nickel, nitrates, sulfate, and the like.

Carbon water filters are able to remove organic chemicals from the tap water because the carbon is naturally charged with positive ions which attract the negative ions in pollutants; this process of removing chemicals from the water improve the taste and smell of the water but also make it better for the body because the chemicals found in the water with out the carbon water filter can be harmful to people.

Carbon filtration cartridges need to be changed frequently to maintain optimal chemical removal; the consumer should not wait until the water smells or tastes poor to change the filter, consult the packaging for a recommended replacement schedule. Carbon water filters generally cost a bit less other filtration systems as carbon; especially coconut shell carbon is a renewable source which can be produced inexpensively to meet demand.