Liquid water cannot exist in a vacuum below a few mm. At the normal glow discharge vacuum levels, water is only found in gaseous form.
A glow discharge is normally maintained all the way down to a few microns or, ~ 10e-3 torr. If you still have a glow discharge, after or while pumping a vacuum, your pump has not pulled down lower than about 10 microns (10e-2 torr).
Richard Hull
Created on Thursday, December 21, 2000 2:49 PM EDT by Richard Hull