To prevent the growth of bacteria in the activated carbon, the filter contains silver. In accordance with drinking water standards in some regions, such as Taiwan, and the Code of Federal Regulations (CFR) in the USA, the limit for silver in drinking water is 0.05 mg/L and 0.1 mg/L respectively. During the filtration process, the filter releases a very small amount of silver – less than 0.05 mg/L – which is harmless to the human body.