Ordinary tap water is full of sediments and minerals. It's these impurities that cause spotting and streaking when tap water is left to dry on a surface. We purify our water by passing it through a series of filters and resins [making use of natural processes like reverse osmosis and deionization removing all dissolved solids from the water], resulting in pure water that dries spot free and crystal clear. Your home is important to you. House windows get dirty, really dirty. We are here to service your residential window cleaning needs with the highest standard of quality available.