If you’re in a rush and your car’s exterior looks a mess, then it may be tempting to run a hose over it to try and make it look presentable. But in this article, I’ll be talking about the three reasons why washing your car with only water, isn’t such a good idea.
The Quick Answer
Washing a car with just water will not remove much dirt, and can cause water spots and result in scratches if you use a mitt or sponge without a shampoo. You should only ever rinse without washing if you are using distilled water, or have a hydrophobic coating and plan to drive the car afterwards.
Why It Won’t Work
So when you’re trying to wash your car with just water, and no car shampoo, then you’re probably considering one of two approaches.
- Giving the car a rinse and leaving it
- Rinsing the car, running a mitt, sponge or brush over it, and rinsing again
Spoiler alert, option two is much worse.
If you go with option one, then you’re likely to run into water spots (making the car look even worse) and it’s unlikely to remove much (if any) of the dirt, unless you’re using very high pressure. If you’re thinking of going with option two, then you will definitely scratch the car.
Now let’s take a look a proper look at the three reasons why washing your car with just water is a bad idea.
If your plan is to rinse your car down and let it air dry, or even drive it to dry it off, then you’ll very likely get water spots. There are only two occassions where this won’t happen.
- If you’re using de-ionised (distilled) water
- If you have a very water-repellent wax, sealant or coating that sheets water off the surface completely
However, for the vast majority of car owners, you’ll experience ugly water spots if you just rinse your car down, even if you drive it afterwards.
Not only do these water spots look terrible and actually end up making the car look dirtier, but they also damage the paintwork.
It’s not actually the water that causes this spotting effect, but the impurities in it, that’s why distilled water isn’t an issue. These impurities are usually chemicals (sometimes acidic) and minerals. They dry on the surface and if left to sit, can actually corrode the paintwork. This process is known as water spot etching.
The longer you leave it, the higher the risk. Also, the more difficult they are to remove. If they’re left for too long then they can actually cause permanent staining that’s very difficult to tackle.
So it’s never really a good idea to let your car air-dry. Take a look at this article on the best ways to dry your car for some more information.
Scratches and Swirl Marks
This is the biggest issue with washing your car with just water and no shampoo. If you are using a wash mitt to wipe the panels down, then you’ll almost certainly cause scratches. You’ll 100% cause scratches if you use a sponge or brush. Check out these articles to learn more.
Your car’s paintwork consists of several layers. The clear coat sits on top of the colour (base) coat underneath. This clear coat is responsible for making your car look shiny.
The flatter the clear coat, the shinier the paint. Any scratches or imperfections cause the paint to look dull and also can be clearly seen in direct sunlight. They often look like spider webs or swirls.
The clear coat is actually very delicate, and can be really easily scratches when washing. The main causes are improper tools (sponges or brushes) and poor lubrication.
Water isn’t a good enough lubricant, so whenever you wipe dirt or dust over the paint, it’ll cause scratches. Instead you’ll need to use a good quality car shampoo (never dish soap) and a microfiber wash mitt to properly clean the paint.
It Won’t Remove All the Dirt
The final issue with washing your car with just water, is that it actually isn’t that effective. Rinsing your car down with just water, even if the pressure is high, is unlikely to remove much dirt.
High pressure water will remove loose dirt and debris that usually builds up on the lower skirting or behind the wheels, however it won’t effectively remove the layer of traffic film that’s built up on the car.
Muddy water that’s splashed up after driving in the rain, bird poop and water spots will not be removed with a quick rinse. You’ll need to use a car shampoo and wash mitt, or a snow foam (or other pre-wash) to break down the layer of grime so it can be effectively removed.
So, Is It Ever Okay?
The only time I would recommend rinsing your car down, and not continuing with the proper wash, is if you are about to drive it on a high-speed road and it has a very water-repellent coating, or you’re using de-ionised water to rinse it.
However the results are likely not going to be that great and the car will still look pretty dirty.
Never use a wash mitt with just water, or you’ll inevitably cause scratches and swirl marks and wish you’d just have left the car looking dirty!
What to Do Instead
Instead of washing your car with just water, you should use a car shampoo and a microfiber wash mitt to effectively clean it safely (without scratching).
If you’re in a rush and your car isn’t that dirty and only has a very light layer of dust, then you can consider using a water-less wash product. This is usually applied as a foam or spray and lubricates the paint as you wipe it with a microfiber towel.
This is a quick technique and is less likely to cause scratches. However if your car is much more than slightly dirty, you can damage the paintwork using this method.
Often it’s just best to wait until you have time to wash it properly yourself. Never take your car to an automatic car wash as they will definitely scratch the paint, and be careful with quick hand wash stations as they also carry some risk of scratches.
Thanks for reading! I hope you’ve found this article helpful. Don’t forget to check out the rest of the website to learn everything you need to know about keeping your car looking clean and shiny.