Total organic carbon (TOC) is the measure of the level of organic molecules or contaminants in purified water. TOC is an analytic technique that helps organizations understand whether the water they are using is pure enough for their processes. All water, no matter how pure, contains some carbon materials. Many of these materials are introduced into the water from the water source, or from materials and systems during purification and production. They can also come directly from workers involved in the processes. They may include natural or altered products of living systems or man-made and synthetic compounds.  

In the pharmaceutical industry, high purity water is a key ingredient used throughout the production processes. Ensuring that the purity of the water helps to eliminate the impact that bacteria and other organic compounds may have on product quality. Organic compounds combine with other elements to produce molecules that can prove harmful to products and to the environment once the water is discharged. In addition to water purity levels, TOC analysis can also provide validation of the cleaning methods companies use for maintaining drug-manufacturing equipment.