There are many excellent carbon, carbon block and carbon/ceramic filters available to consumers. These filters are capable of efficiently removing chlorine, chlorination byproducts (e.g., THMs), organics and pesticides. They can be combined with other additives to also preferentially remove arsenic and lead.

Current carbon filters have, however, several notable drawbacks. All activated carbon filters are not made of the same carbon and some carbons like coconut shell carbon are more highly absorbent of certain hydrocarbons than coal-based carbons, which are primarily designed to remove chlorine. In addition, certain specialty carbons like catalytic carbon can remove non-organic compounds like chloramines much more effectively than coconut shell carbon.

They have problems, though, accumulating bacteria over time and then releasing these bacteria, which can be harmful, directly into the user’s drinking water. As a result, carbon filters are rated for specific pollutants and for a specific period of time…usually 6 months to a year.