At what point may water be used during the performance qualification of a water supply system?

During Phase III or long-term phase, the water can be used for pharmaceutical manufacture. The quality is monitored in accordance with the previously defined sampling plan.

From a regulatory point of view, an "at risk" release is theoretically possible. However, if PQ Phase II is not successfully completed, the products manufactured during this phase must be destroyed.

[GMP Compliance Adviser, Chapter 5.D]

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