Washing Cars With Hot Water: Is It Safe For Your Car?

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guy washing a car with hot water, illustration

You’ve probably come to the idea of washing a car with hot water to wash off the dirt more easily. And if you’re wondering if it’s safe for your car’s paint and whether you should do it or not, this post is for you.

Key Takeaways:

  • Never wash your car with hot water, especially in the winter period.
  • Only wash cars with warm or cold water (ideally warm).

Is Hot Water Good For Washing Cars?

Hot water is a fantastic cleaner, especially when paired with some car wash products. However, you should never use hot water to wash your car.

The most important reasons why you shouldn’t use hot water to wash your car:

  1. It isn’t suitable for car paint: if used together with a high-pressure washer, it can destroy car paint more quickly than cold water, resulting in rust.
  2. Hot water breaks up waxes and sealants: car paint protectants are resistant to temperatures, but only to a certain level. Hot water will break them, which leaves your car’s finish unprotected.
  3. Car windows may break: Washing your vehicle during the winter period and using hot water may lead to windows cracking because of the big temperature difference. 
  4. It’s too hot for your hands: using hot water inside your car wash buckets is a mission impossible. It’ll quickly burn your skin.
  5. Hot water destroys microfiber cloths: you’ll spend too much money on ordering new wash mitts because the fibers in the old ones will melt from hot water. 
  6. You may lose car stickers: if you have some stickers on your vehicle, hot water may melt the glue beneath, and they will probably fall off. 
  7. Car wax may come off: Hot water will strip the wax off, meaning that you’ll have to reapply it to the car.

I think that these seven reasons are more than enough explanations of why you shouldn’t use hot water when washing cars, motorcycles, RVs, trucks, etc. 

Warm Water Is Best For Washing Cars

is it safe to wash a car with hot water

You should always aim to wash cars with warm water since it’s warm enough to lift the vehicle’s dirt quickly but is still safe enough for car paint, tools, and protectants.

The ideal water temperature for washing cars is anywhere between 100-130 degrees Fahrenheit (37 to 54 Celsius). The water temperature shouldn’t exceed 140 degrees Fahrenheit (60 Celsius).

Every self-service car wash has warm water, and that’s with reason. It just lifts the dirt from the vehicle better, and together with high-pressure washers, it’s a win-win. 

Warm water could be a great addon to speed up your car detailing tasks (it can also reduce the amount of water for washing cars), but it’s not crucial for washing vehicles. 

It can be pretty expensive to install a dedicated car wash boiler for your auto detailing garage. So, if you’re not a professional detailer, I think there’s no need to buy boilers. There’s no ROI that way.

Cold Water Is Still Most Commonly Used

Even though warm water is the best solution for washing vehicles, many people still use cold water to wash their cars. That’s because it’s hard to implement water boilers inside a garage or the water system outside of the house.

For instance, mobile detailers don’t have any chance of implementing water systems in their mobile detailing setups, and even without warm water, they get great results for washing vehicles.

“Warm water is better, but cold water will do the job. In the end, if you have great knowledge and experience, together with high-quality products, you’ll always get perfect cleaning results, even with cold water only.”

If you follow the main principles of washing vehicles correctly, you’ll wash cars without any problems, regardless of the warm or cold water you use for washing.

I said that the ideal water temperature for washing vehicles is between 100-130 degrees Fahrenheit. However, any temperature between 50-130 degrees Fahrenheit is good and will wash cars properly.

TIP: Use Warm Water Inside Car Wash Buckets

warm water inside bucket for washing car

There’s one thing that you can always do to improve the effectiveness of car wash shampoos, and that’s by using warm water inside your car wash buckets.

When washing with the three-bucket system, fill buckets with warm water instead of cold water. That way, when doing a contact wash, you’ll lift the dirt from the vehicles, and you’ll get slightly better results.

That’s how I do it sometimes (for extremely dirty vehicles), and I find it quick and easy. So, it shouldn’t be a problem at all.

That’s also a perfect method when you’re washing cars during the winter period, especially in below-freezing temperatures. Water will be warm so that it won’t hurt your hands, and you’ll be able to work all day. 

So, for contactless wash (pre-wash, foam, rinsing, etc.) – use cold water. For contact wash (buckets and wash mitts) – use warm water. That’s the easiest way to work quickly and get fantastic results.


As you can see, you should avoid washing cars with hot water. Instead, use warm water if possible. If not, don’t worry. You are perfectly fine with cold water, too.

If you’re a professional car detailer who works in his garage, I recommend you think about buying a boiler so that you can have warm water inside your detailing garage. It will be beneficial for more things than just washing vehicles. 

However, cold water (what you already have in your house) is the best and cheapest solution for most hobbyist car detailers. 


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