MANTLE Blog · Updated March 2026

What Is Purified Water
Window Cleaning?

The science behind spot-free glass. Why it matters in Toronto. How ClearCoat™ works.

Every window cleaning company in Toronto uses water. The question is: what's IN that water? Standard Toronto tap water contains 300+ mg/L of dissolved calcium, magnesium, and other minerals. When that water dries on your glass, those minerals stay behind as a white, hazy film. Purified water contains 0 mg/L of dissolved minerals. When it dries: nothing. Just clean glass.

Tap Water vs Purified Water — Visual

🚰 Toronto Tap Water

300+ TDS
  • Calcium carbonate deposits
  • White haze in sunlight
  • Mineral buildup over time
  • Glass etching after 18 months
  • Dirt sticks to mineral residue
  • Needs cleaning every 3-4 months

💧 ClearCoat™ Purified

0 TDS
  • Zero mineral deposits
  • Crystal clear in all light
  • No buildup — ever
  • Glass protected from etching
  • Dirt slides off clean glass
  • Stays clean 2-3x longer

How It Works — The Science

Step 1: Multi-Stage Filtration

Toronto tap water passes through sediment filters (removes particles), carbon filters (removes chlorine and organics), and finally deionization resin (removes ALL dissolved minerals). The output: 0 TDS water — pure H2O.

Step 2: Application

Purified water is applied to windows via water-fed poles (for exterior) or hand-cleaning (for interior and heritage glass). The purified water acts as an aggressive solvent — because it contains no minerals, it actively absorbs and dissolves minerals OFF the glass surface.

Step 3: Air Dry

Unlike tap water cleaning (which must be squeegeed before minerals dry), purified water can air-dry without streaking. The result: completely spot-free glass with zero residue. No minerals deposited. Nothing left behind except clean glass.

Why Toronto Specifically Needs Purified Water

Not all cities have this problem equally. Toronto's water is drawn from Lake Ontario — a large, mineral-rich freshwater lake. The TDS (total dissolved solids) varies by area:

For comparison, "soft" water is under 60 TDS. Every area of the GTA exceeds this by 2-4x. Every area benefits from purified water cleaning.

The Long-Term Savings Math

Purified water cleaning costs approximately the same as standard cleaning ($0-$50 more). But windows stay clean 2-3x longer because there's no mineral residue for dirt and pollen to adhere to. Over a year:

ScenarioAnnual Cost
Standard cleaning 3x/year @ $249$747
Purified water 2x/year @ $274$548
Annual savings with purified water$199/year

Purified water doesn't cost more — it costs less over time.

ClearCoat™ is MANTLE's proprietary purified water system. Every MANTLE cleaning uses 0 TDS purified water at no extra charge. It's not an upgrade or add-on — it's standard on every job. Because in Toronto's hard water, anything else is leaving minerals on your glass. Learn more about ClearCoat™ →

Experience the ClearCoat™ Difference

0 TDS purified water. Every job. No extra charge. See the difference on your own glass.

Get Free Estimate →

ClearCoat™ Technology · Hard Water Stains Guide · All Posts