Activated carbon has a much higher adsorption capacity than other materials. Carbon adsorbs objectionable odours, flavours, organic compounds and many hazardous chemicals.

There are two types of carbon filter system (i) granulated carbon and (ii) solid carbon. A process of heat treatment creates 'activated' carbon with microscopic 'pores' that trap chemicals and organic impurities.

Advantages: it removes dissolved organic compounds. H₂S, radon, chlorine, pesticides, volatile organic compounds (VOC's) etc.

Disadvantages: this process generally does not remove heavy metals.