How Professional Window Cleaners Actually Work

The traditional method and its limit

A wetting agent, a scrubber and a squeegee, finished by hand at the edges. In skilled hands it produces excellent glass. Its weakness is that the wetting agent is soap, and soap leaves a film by design. That film attracts dust, so soap-cleaned glass starts dulling within weeks rather than months.

What pure water cleaning does differently

Water is run through a filter that strips out its dissolved minerals, producing deionized water. Because it carries nothing, it aggressively picks up dirt and then dries without leaving anything behind. The glass is scrubbed with a brush on a pole, rinsed, and left to dry untouched. There is no squeegee, no cloth on the glass, and no residue.

Why nobody wipes it dry

This is the part that looks wrong to people watching. Wiping is what introduces streaks, because it redistributes whatever is in the water. Pure water has nothing in it, so the correct finish is to rinse and walk away. If you can see the crew leaving windows wet, that is the method working rather than a job half done.

Where the ladder still comes out

Poles reach roughly three storeys from the ground, which covers nearly all residential work. Deep recesses, glass behind mature landscaping and windows above a lower roof still need ladder access. A company that only owns one approach will either skip those or improvise, and it is fair to ask how they plan to reach a specific window.