Water

Water quality is usually defined in terms of chemical and bacteriological purity,
particulate matter content, and endotoxin levels. Potable water is normally from
the municipal water system, which may have been treated with chlorine to control
microbiological growth. Soft water and deionized water have undergone ion
exchange or similar treatment to eliminate unwanted ionic species, such as Mg2+
and/or Ca2+. Purified water, water for injection, and other types of water meeting
compendial specifications are produced by ion exchange, reverse osmosis, distillation,
or a combination of such treatments.
The validation protocol provides a detailed description of sampling locations
and requirements, testing methodology, and test limits or specifications.
Sampling and testing can be performed daily during qualification and validation.
When the system is in routine use, following the validation the testing frequency
can be reduced to a weekly schedule for monitoring purposes.
An action guideline of not more than 10 CFUs/100 ml for bacteriological
purity is suggested. As with the purified water system, the sampling and testing
frequency for the water for injection (WFI) system is defined in the protocol
and can be reduced after the system is qualified and validated.