What causes water spots on cars?
Water spots are minerals left behind when water evaporates on paint or glass. Hard water carries more dissolved minerals, so it leaves more visible spots — especially when it dries in the sun.
Tap water contains dissolved minerals such as calcium and magnesium. When a droplet evaporates, the water leaves but the minerals stay, forming a ring or dot on the surface.
Fresh spots usually wipe or rinse away. Spots left to bake in heat for a long time can bond to the clear coat and become harder to remove.
The most reliable prevention is to rinse with low-mineral (filtered or deionized) water and dry the vehicle before water can evaporate on its own.
Why this matters in Palm Desert
Coachella Valley water is generally considered hard, and summer heat evaporates droplets quickly — a combination that makes spotting more likely after a home wash or sprinkler overspray.
How Genius fits in
Genius is designed around a filtered spot-free final rinse followed by high-velocity drying.
Updated · General guidance, not a professional inspection.