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Deionized vs Distilled Water for Detailing – When to Use It!

As a detailer or just a car enthusiast, you may have heard by now that distilled water is better at washing your car than standard water from the tap. But why is this true, and do all detailers use distilled water? What about deionized water?

In this blog, I’ll break down what all this terminology means and when you might want to consider using a form of purified water.

Deionized vs distilled water

Okay, some technical talk. Technically speaking, distilled water is just a type of purified water produced by a process called distillation. You probably understand this process, it’s basically applying heat to water, causing steam.

This steam condenses, and what results is water that is free of hard minerals like calcium. You can pick up distilled water by the gallon at the grocery store or just about anywhere.

Deionized water is another purification process that produces purified water using an ion-exchange resin often times (or filter). The minerals like magnesium, calcium, iron and others that cause water spots (negative ions) are exchanged for positively charged ions (like hydrogen).

Most of the time ‘distilled water’ you find in the jug is actually just deionized water, but not always.

If you look closely on the jug, distilled water is usually recommended for ironing, appliances, and other household uses like rinsing cars. It is technically safe to drink, but won’t taste great, since all the minerals have been removed.

All you really need to know is that both types of water will be free of impurities that cause visible water spots which is the main reason detailers use it.

When to use distilled water as a detailer or DIY-er

Many detailers and car enthusiasts use distilled water to prevent hard water spots; detailers commonly use it for diluting products or rinsing a vehicle.

Rinsing everything as a last step with distilled water can help prevent hard water spots caused by rinsing with tap water.

Many people use a product called ONR (Optimum No-Rinse) with distilled water, which is just a rinse-less wash concentrate that you dilute with water. It’s a good choice if you need to conserve water or don’t have access to a water source.

Use case: Rinsing your car with deionized water 

portable deionizer for washing your car

 If you prefer convenience, a portable water deionizer is a proven way to get your vehicle spot-free. Simply change the filters from time to time, and never deal with hard water spots agian.

In the last few years, these portable deionizers have become popular and affordable. The most common units I see are made by CR Spotless and can be found on Amazon or detailing shops.

CR Spotless Water System

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cr spotless hard water spot remover unit

The benefit of a deionizer water system is you that can spray purified water directly on your vehicle from the hose without grabbing distilled water and an extra bucket.

You also have the option of installing a water-softening system throughout your house if you have hard water. Check out my post Washing Your Car with Hard Water? 3 Spot-Free Solutions for more information on what options may work best for you.

Use case: cleaning car carpet and upholstery

best carpet extractors

Another great use case for distilled water is for cleaning upholstery in cars or carpets. If you operate steamers or carpet extractors you probably won’t notice a huge difference, but softer water does tend to clean better and is less likely to leave water marks or stains on certain types of upholstery.

It’s also a good idea because it will not leave mineral residue in your tank or water lines.

Use case: Mixing concentrated products

Whenever mixing any type of concentrated detailing product in a spray bottle (for example), it’s best to use distilled water. If not, minerals found in hard water can make the solution less effective.

Especially when removing water spots with an isopropyl alcohol wipedown (prior to paint correction), you’ll always want to use purified water.

Use case: distilled water at car washes

If you find yourself at a self-service car wash, you may notice the ‘spot-free’ rinse option provided. These car washes usually purchase distilled water or water with mineral dissolvers to achieve a spot-free rinse..

If you do occasionally frequent self-service car washes, try the spot-free rinse option and compare your results to the water in the standard high-powered rinse.

Benefits of purified water in detailing

To recap, here are a few common reasons why distilled and deionized water are preferred for cleaning in detailing:

  • Can eliminate odors sometimes found very hard tap water
  • Dilutes chemicals properly without introducing extra minerals
  • Dries faster than tap water (with no water spots left behind)
  • Deionized water lack ions to conduct electricity and can be used to clean electronics
  • Better prepares the clear coat for waxing or sealants. Claying may be needed if tap water is used.

Conclusion

Now that you know the difference between distilled water, deionized water, and tap water, try comparing the results you get from switching to more purified water during the rinsing process. Another benefit is that you really don’t have to worry as much about drying your car wish towels or chamois, which is great for your clear coat. The less touching your clear coat the better.

If your water is already pretty soft, distilled water may not be worth the extra cost of buying water. One trick I’ve heard about is to unscrew the hoze nozzle when rinsing off suds, letting a wide stream of water run down your car. Spraying is what really causes water beads, so give this trick a try.

Have any other suggestions for using purified water when washing your car? Leave a comment below.

Baxter Overman is the founder of Carwash Country and has been been cleaning up dirty vehicles for nearly 20 years. Since 2017, he's helped thousands of beginners see better results by learning the fundamentals of washing and detailing. He's on a mission to make the car wash process more fun...and way easier.

1 thought on “Deionized vs Distilled Water for Detailing – When to Use It!”

  1. Choosing which type of water to drink might seem simple, but there are multiple types available — and you might not like the taste of all of them. Drinking water encompasses a wide range of different waters, including distilled water .

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