What's the Best Way to Clean Windows Without Streaks?
Streaks are a water problem, not a product problem
Most people assume streaky windows mean they bought the wrong spray. In practice, the biggest cause is Chicago's hard water. Tap water carries dissolved minerals that dry on the glass as a thin white film — no amount of extra spraying fixes that, because you're just adding more mineral-loaded water to the surface.
Professional window cleaners get around this with purified or deionized water systems that leave zero mineral residue behind. That's also why a window can look perfectly clean right after washing and then show streaks a few hours later, once the water fully evaporates and the leftover minerals become visible.
The method that actually works
Work in the shade, not direct sun — sunlight dries the cleaning solution too fast, before you've had a chance to squeegee it off evenly, which is what causes those arc-shaped streaks. Use a squeegee rather than paper towels or newspaper for anything larger than a small pane; a rubber blade pulls water off in one continuous sheet instead of smearing it around.
Microfiber cloths are the safest way to dry the edges and corners the squeegee can't reach. Avoid ammonia-based glass cleaners on tinted or newer low-E windows — they can degrade the coating over time. A simple mix of warm water with a few drops of dish soap, applied and then squeegeed, outperforms most commercial sprays.
When it's worth hiring a professional
Second-story windows, storm windows that need to be removed and cleaned separately, and hard water stains that have built up over multiple seasons are where DIY starts to break down. Hard water etching in particular can't be wiped away — it needs a mineral-deposit remover applied correctly, or the glass can end up permanently hazy.
We clean residential and commercial windows across Chicago and the North Shore suburbs using purified-water systems specifically to avoid the streaking problem at the source, and we offer dedicated hard water stain removal for windows that DIY methods haven't been able to fix.
Before & After
Residential Windows
Before
AfterHard Water Stains
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