Ceramic water filters work by simply allowing the water to seep through tens of millions of pores in the water cartridge surface. In the process, organic and inorganic particulates too large to pass through (often anything larger than 0.5 micron) accumulate on the ceramic surface.  As a point of reference, even cysts (like Cryptosporidium and Giardia) are too big in size to squeeze through the tiny pores of the ceramic filter cartridge.

Contaminants that may pass through the outer surface of the water filter cartridge are likely to be intercepted within the ceramic depth. Here inside the ceramic filter, even much smaller particles can be captured. This is because any remaining particulates in the water have to navigate through an intricate maze. This labyrinth of twists and turns involves so many sharp angles that contaminants that may have penetrated the topmost layer become trapped within the underlying complicated structure of the ceramic.

Many ceramic filters also incorporate a silver compound into the ceramic itself, because it acts as a bacteriostatic agent to repel bacterial growth in and on the filter. A granular activated carbon core may also be added to the ceramic core to reduce chlorine and other undesirable taste & odor issues–as well as pesticides.

Ceramic filtration does not remove chemical contaminants per se. However, some manufacturers (especially of ceramic candlefilters) incorporate a high-performance activated carbon core inside the ceramic filter cartridge that reduces organic & metallic contaminants. The active carbon absorbs compounds such as chlorine.