Is Washing a Car with River Water Harmful to the Paint?
3 Answers
Washing a car with river water can cause damage to the vehicle. Here are the specific details: 1. River sand: The main components are silicon, calcium, and other substances. It has a hard texture; after being washed, the surface of some river sand may become slightly smoother. However, the diameter of river sand is too fine, and when it rubs against the car's surface, it inevitably scratches the paint. 2. Chemical pollutants: The most harmful pollutants in river water for cars include hydrogen cyanide, potassium cyanide, sulfuric acid, nitric acid, and other chemical pollutants discharged from industrial areas such as electroplating plants, tar plants, and fertilizer factories. If these pollutants are too concentrated, they can directly corrode the car paint and seep into the car's interior, damaging the components. Even trace amounts of pollution can alter the pH value, accelerating the oxidation of the car body.
I've been driving for over a decade and always paid great attention to car maintenance. Washing cars with river water is really not advisable – there's too much sediment in rivers. When washing, sand particles get dragged across the car body with the cleaning cloth, acting like sandpaper that gradually scratches the paint. This is especially noticeable on light-colored paint – just a few washes with river water will show fine scratches that become particularly visible under sunlight. Moreover, river water may contain acidic substances or industrial pollutants that can make the paint look dull over prolonged use. Last week, my neighbor's white car developed yellowish spots after half a year of river water washes. In my opinion, it's better to use tap water or spend twenty yuan at a professional car wash. They use filtered soft water with pH-neutral detergents that are much gentler on your car's paint.
From a water quality perspective, washing cars with river water poses significant risks. Suspended particles in river water can easily scratch the transparent layer of car paint during wiping, and those micro-scratches will reduce the paint's reflective effect. More troublesome is the high content of calcium and magnesium ions, which tend to leave white scale spots on the car body after washing—similar to limescale in kettles and equally difficult to remove. I've tested the pH of local river water, which sometimes leans alkaline and can damage the protective layer of car paint. Additionally, river water near industrial areas may contain heavy metals, and long-term use can lead to paint oxidation and discoloration. In contrast, professional car washes use deionized water with palm wax car wash solutions, which not only clean but also form a protective film. While river water is free, the damage it causes is irreversible, and paint repair costs can be ten times more expensive than a car wash.
