Ceramaji water filters are made with local clay and temper material. Clay is collected from a site within 20km of the manufacturing plant, and sawdust from a local sawmill is used for temper. The materials are mixed, pressed, and fired in a kiln to burn off the organic temper, leaving micro pores to filter bacteria and other contaminants. The filter is then dipped in colloidal silver solution, which serves as an antiseptic.
Biological testing in a microbiology laboratory at the University of Alberta in Canada has shown the filters to have over 99% efficacy in removing fecal coliform bacteria from contaminated water. In addition, the filters undergo biological screen testing onsite in Kenya using a Wagtech portable microbiology kit, in order to maintain product quality and efficacy standards.