The goal of pharmaceutical water system operators is to produce bacteria-free water that meets or exceeds required purity standards. Water systems use several filters to protect system components and to assure that the water dispensed for use is free of bacteria and most other particle contaminants.

WFI systems utilizing distillation coupled with storage and distribution systems that are kept at elevated temperatures need no additional filtration since the water has been rendered sterile and is maintained in a sterile state with heat. However, Purified Water systems may utilize either heat or filtration as the final treatment step during distribution to points of use. Some systems may also utilize UV lights for bacteria control, and install filters after the units to capture cell debris.

Purified Water _ Water for Injection System Design (Distillation)

Due to the many possible entry points for bacteria into any system, final filtration utilizing Pharmaceutical Grade (also called sterilizing grade) membrane filters will often be used in ambient temperature pharmaceutical water systems at the point of use. Typical sterilizing grade filters used in water systems are rated to remove particles and bacteria that are 0.22 or 0.1 microns or larger in size.

Some systems may use a filter to remove endotoxins (cell fragments). Ultrafilters or charge-modified filters are the frequent choices for this function.

Critical Process Filtration offers several products to meet the requirements for bioburden reduction and sterilizing filtration. Biopharmaceutical Grade filters are bioburden reduction filters made using symmetric or asymmetric polyethersulfone (PES), polyvinylidene fluoride (PVDF), and Nylon 6,6 membranes.

Pharmaceutical Grade products include membrane filters made from asymmetric PES and Nylon 6,6. Both are available with either a 0.1 μm or 0.22 μm pore size rating as well as larger pore sizes.

Each facility and water system design is unique.
The particles in the source water also vary, and can significantly change the filter
steps required and types of filters used.


To explore filter solutions for pharmaceutical operations, visit Process Filtration Products on our website.

Looking for suggestions on how your facility might get better performance from your water filtration system, assure water quality, and potentially reduce your costs? Email us with concerns or questions at or call us at (603) 880-4420.