The use of purified water (PW) and water for injection (WFI) in the production processes is very common in the pharmaceutical industry. These systems are represented by two main stages: water production and its storage and distribution. The assembly consisting of a storage tank and a distribution loop is called a purified water (PW) loop or a water for injection (WFI) loop.
The difference between the purified water (PW) and water for injection (WFI) is mainly based on their physical, chemical and microbiological properties. The main differences are briefly described below.