Short answer
Pure-water window cleaning scrubs glass with purified (deionized) water through a brush on a water-fed pole, then rinses it. Because the water has had its minerals removed, it dries spot-free — with no soap film left behind to attract new dirt. It also lets crews clean many upper windows safely from the ground.
Why purified water dries clean
Water spots are just minerals left behind when water evaporates. Remove the minerals first and there's nothing left to spot. That's why pure-water cleaning can leave glass wet and still dry clear, and why it works so well on black frames and big panes that show every mark.
No soap, no film
Traditional soap-and-squeegee cleaning works well, but any soap left at the edges becomes a sticky film that grabs dust. Pure water rinses everything away and leaves nothing behind.
When we use it — and when we don't
At Pro Solutions we use purified water and water-fed poles for most exterior glass, especially second-story and hard-to-reach windows. Interior glass, decorative or older glass, and detail work are cleaned by hand with a squeegee and towel. Pure water won't remove baked-on hard water spots by itself — those need a separate treatment.
Rather have a pro handle it?
Pro Solutions does window cleaning across Boise and the Treasure Valley. Quotes are free, itemized, and usually texted the same day.