Never Wash Your Car with Rainwater

Most car owners want to save money. Green activists may have actually never spent a penny on cleaning their car, relying only on occasional rainfall, or collecting water from streams or lakes to clean their autos. While some do both, there’s no telling what type of water car owners use to clean their vehicles.

While rainwater is literally a free car wash service from the skies, it can actually damage your cars in more ways than one. Here are some of the reasons why you should never wash your car with rainwater, and a better idea is to visit Fast Eddie’s instead.

1.  Rainwater is corrosive.

According to chemists, the pH of rainwater depends on several variables. Water with neutral PH falls on a 7, while more acidic rainwater will have a pH of below 6 or 5. This type of rain occurrence is more common in heavily urbanized areas.

Certain metals already interact with water that is slightly acidic. Examples of these metals include magnesium, zinc, and iron. Car exteriors are made with steel that contains aluminum.

While aluminum does react weakly with acids, it’s not corrosion-proof, and prolonged exposure to rain water will eventually wear the metal out. Consult with your car manufacturer to check if the exterior  can resist corrosion from weak acids.

2.  Rainwater leaves nasty marks on car paint.

When water evaporates, it’s not just water molecules that go into the atmosphere. There will be trace amounts of metals or minerals from the ground, up until the tallest skyscrapers.

The minerals that the droplets will pick up along the way are the very same minerals present in “hard water”. When hard water dries up, they leave white stains on everything. That’s why old kettles will have white residue at the bottom – these are minerals left over from boiling water.

These can be very hard to remove, and most stain removal compounds aren’t friendly with car paint either – water mark removal becomes more of a problem than a solution. DIY remedies for removing water marks on car paint include vinegar and soft water.

3.  Rainwater is extremely dirty.

Most of the time, rainfall is a source of life for critters and plant life. It’s even shown to clean the air in a city. The latter is beneficial for humans to enjoy fresh air, but is detrimental to cars.

Rain does not only become acidic due to the air pollutants emitted by industries and the everyday byproducts of the hustle and bustle of a city. Rain also contains contaminants that can leave your car dirtier than it started. Sure, you will see dust cleared from the sides of the tires, but rainwater will have a more profound effect on white cars.

Rain contains particles of exhaust. This is seen as a grey haze over a city. If it rains, it will stick to the car’s surface. That’s why you’d feel sticky after a downpour – all the city’s airborne grime is on your skin. You’d want that off as soon as possible.

4.  Rainwater can damage even if it’s alkaline.

You’ve heard of health fads about alkaline water doing miracles for the human body. But that’s just regular water at a pH of 7. On the opposite end of an acid rain is alkaline rain – a similarly damaging meteorological occurrence that often goes overlooked.

So the concept is basically the same – cities have gas pollutants that may or may not contain alkaline compounds. These contribute to a rainwater pH that’s higher than normal, and metals in the car exterior will react to anything that is considered corrosive.

Bleach, for example, is a strong alkaline. It’s not acidic, but definitely corrosive. What happens if similar compounds get diluted in rainwater and fall on your car? Staining, damaged car paint, and repair costs are sure to follow. Just make sure you check the weather forecast and just put your car in the garage.

These are just some of the reasons why you should never, ever wash your car with rainwater. Just go visit a carwash station, and you might just get a free polish. It’s worth every penny.

Category: Tips

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