The effect of rainwater on your car paintwork will shock you

Felix Lin

Car washing, it’s one of the most grueling and meticulous parts of maintaining a good car. It requires seriously attentive effort to ensure that the car is spotless, clean and in its top form.

Which begs the question, should you wash your car before or after it rains?

Then again, this raises more questions like, does it really matter when I wash my car? Will rainwater make my car dirtier or cleaner when I use it for washing? In this article, we look into all these questions and more, and find out when is the perfect weather to start washing your car.

To start off, we need to understand the effects of rainwater on a car. Rain, as we know it, is the moisture of water in the air condensed from the atmosphere that falls into droplets, so that must mean that the water from the rainfall is pure and good enough to wash the car, right? Not true. People think that when the car is seated under the rain, the water will wash the dirt and contaminants off the car. This is WRONG for 2 Reasons:

1. Contaminants in Rain

Actually, rain water can cause even more damage than it helps. This is because as rain falls, it collects pollutants and contaminants from the air, forming what is known as acid rain, which causes it to etch its way into the paint and damage your car’s surface. What’s left is essentially a thin layer of pollutants and the longer you leave them there, the more damage it can inflict on the paint surface. (However, in general a modern vehicle’s surfaces are highly resistant to rainwater, so there’s no need to worry if you get wet driving around town.) But a protective coating will help even more.

2. Pressure

Additionally, rainwater is also not as strong when it comes to wiping off the stains off a car, since it merely provides a light rinse which only creates mud and streaking. Even a strong rain does not have adequate pressure to remove dirt and there will always be a layer of grime that the rainwater won’t be able to dislodge. Overall, rainwater is not such a good idea as a way to wash your car. You actually need the high pressure of a commercial washer to remove all the dirt and contaminants.

We did an very unofficial (and somewhat casual)  survey to find out what people think. We found the following:

  •  Some people find it a waste of time to clean it all up only to have it rain on it the next day, and would wait until after the rain to wash their cars.
  • Most people noted that rainwater leaves water spots on the car.
  • Some people found that washing their car before the rain the spots wouldn’t appear.
  • A few people felt that the rain will turn the existing car surface dirt into a bigger mess, especially if that car is outside while it rains those rain droplets rub that dirt into your paint and potentially cause some sort of defect.

So Who is Right?

The funny part is they both are in a way.  For some, getting their car washed before the rain may seem a waste but people tend to wash them anyway. For those who waited till after the rain, they find their car is actually dirtier. For our part, given the frequency (and unpredictability) of rain in Singapore, it doesn’t really matter. When you wash your car, it’s always after the last rain, and before the next one. Which can happen in the same day anyhow.

However, jokes aside, washing your car, even once every two weeks, can be a great way to protect your car from dirt and contaminants that can eat away at the exterior of your car and create unsightly blemishes in your paint.  The key takeaway: rain does an horrible job at washing your car.

The best way to protect your car, however, is to apply a paint protective coating. These coatings have a hardness level which helps in Anti Scratch Resistance, Anti Oxidation Resistance , durable, and extremely hydrophobic, meaning they repel water.

At EA Detailer, we offer 2 types of Premium Coatings – Diamondbrite Foundation Coating  and Titanium Glass Coating. Both of these coatings protect your car from rain.

To find out more information on how we can help protect your car or to make an appointment with us:

Call us at 6917 8396