This article, written by the American Ground Water Trust was originally published in



Carbon filters have been around for years.  Early sailors knew that water tasted better when stored in charred wooden barrels.  Carbon is extremely porous and its high surface area makes it effective at adsorbing chemicals. [Adsorb means that chemicals are attracted to the surfaces of the carbon].  Activated carbon can remove volatile organic chemicals (VOCs), some chemical compounds and many pesticides. Activated carbon filters are used to eliminate unpleasant tastes and odors caused by industrial wastes, decaying organic matter, dissolved gases, and residual chlorine.  Always have a water test from a certified laboratory.  You don’t want to pay for equipment to remove problems that you don’t have!


The downside to some activated carbon filters is that they can create conditions for bacteria to thrive.  Contact time of the water with the filter is important, and some inexpensive flow-through units may not provide time for the adsorption process to work properly.  An additional problem results when homeowners don’t change the filter cartridges.  With an inactive cartridge, not only may the unit not work, it may be a source of bacteria to the drinking water. 


When correctly installed and maintained, and used in combination with other treatment technology, activated carbon filters can be really effective at removing toxic chemicals.  Make sure your water conditioning sales person is knowledgeable about the basics of chemistry and microbiology.  There is no “one-size-fits-all” solution to water conditioning.


[© American Ground Water Trust.  This article may be reprinted for non-commercial educational purposes provided it is used in its entirety and that reference is made to its source as an article in THE AMERICAN WELL OWNER, 1999, Number 2]