How De-Ionized Water Window Cleaning Works
De-ionized (DI) water is tap water that has been passed through an ion exchange resin that removes all dissolved minerals — calcium, magnesium, sodium, silica — until the water tests at or near 0 PPM total dissolved solids. When this chemically pure water is applied to glass and allowed to dry, it leaves nothing behind. No mineral residue. No water spots. No white haze. Just clean glass.
The contrast with Arizona tap water is stark. Scottsdale and Phoenix metro tap water typically tests at 500–700+ PPM TDS. When tap water is used for window cleaning — whether by a homeowner with a garden hose or a professional with squeegee technique — a portion of that mineral content is deposited on the glass as the water evaporates. The result is the white mineral film and spotting that makes Arizona windows look dirty within days of a standard cleaning.
Why DI Water Is Required for Arizona, Not Optional
In most US markets with 100–200 PPM water, standard professional squeegee technique is adequate — at lower mineral concentrations, film buildup is slow and manageable. Arizona's 500–700+ PPM water is 3–5x higher than many markets, making mineral residue from standard cleaning significant enough to be visible within days. Over time, untreated mineral deposits etch glass permanently — this is the hard water glass etching that cannot be removed by any cleaning method.
De-ionized water window cleaning is not a premium upgrade in Arizona — it's the baseline professional standard for a market with extreme hard water. Blues Home Services exclusively uses purified water systems for all residential and commercial window cleaning throughout Scottsdale and the Phoenix metro.