Total Organic Carbon is a term used to describe the measurement of organic (carbon based) contaminants in a water system. Organic contamination can come from a variety of sources, since "organics" are compounds such as sugar, sucrose, alcohol, petroleum, PVC cement and plastic-based derivatives. Organics may exist in the feed water. Organics may result from the leaching or shedding of various components within the purification or water distribution system. Organics may result from the formation of biofilms (bacteria) in the water system.