 If the unit is dropped or otherwise abused, the brittle nature of ceramic materials can allow fine, barely-visible cracks, allowing larger contaminants through the filter.Work is being done to modify clay/sawdust ratios during manufacture to improve the brittle nature and fracture toughness of these clay ceramic water filter materials.If the "clean" water side of the ceramic membrane is brought into contact with dirty water, hands, cleaning cloths, etc., then the filtration will be ineffective.