Tap water, which is traditionally used in window washing, contains added minerals including calcium, magnesium, and potassium. Hard tap water has a higher mineral content. The minerals in tap water can leave spots or streaks on windows after washing.
The Upkeep Team, Inc. uses pure water window cleaning technology which purifies water by stripping the minerals from tap water through a process known as deionization. Pure water window cleaning combines the purified water with a telescopic pole and brush. The purified water is fed through and up the "water fed" pole" to a brush which is used to clean windows leaving the surfaces clean and spot-free without the use of chemical additives.