You can reduce the opportunity for microbial contamination from your central=20
DI plant by adding a point of use filter to the dispensing outlet in your 
laboratory.  A 0.2µ filter will provide the filtration you require.  The 
filter will require changing and you should run a culture on the water on a 
regular basis.  

The central DI plant may take all the necessary precautions to provide the 
best quality water but the Deionization beds provide a wonderful growth 
medium for any contamination.  In addition, if the piping system from the 
central plant to any of the labs contains a 'deadleg' the system will become=20
contaminated.  A deadleg occurs when any section of piping is not constantly=20
in the recirculation loop.  A single stub of piping can be the source for the 
microbial growth, and if the length of the section of piping is four times 
the diameter, a deadleg has been created.

Regards,
Jim Cannon
e-purewater