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 caused distillation. You probably understand this process, it’s basically applying heat to water, causing steam. This steam condenses, and what results is a water free of those 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. It’s usually just more cost effective to purchase distilled water in jugs as a detailer (vs buying a deionizer).

When to Use Distilled Water as a Detailer or DIY-er

As a detailer or car enthusiast, I would recommend rinsing with distilled water (as opposed to washing your entire car with it). Rinsing everything as a last step with distilled water will pretty much eliminate the appearance of hard water spots caused by rinsing with tap water, and you won’t have to try to remove them with another product.

Many people use a product called ONR (Optimum No-Rinse) with distilled water, which is a 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.

Buying a Deinoized Water System to Rinse Your Car

portable deionizer for washing your car

Do you really need a portable deionizer? Probably not, but it depends on the person. If you prefer convenience and have the money, it is definitely not a bad purchase if you like to keep your vehicle spot-free and it will save time. For the average person, these are a little pricey compared to purchasing water, since the filters must be changed out from time to time (and can be expensive).

In the last few years, these portable deionizers have popped up online and though specialty detailing shops. The most common units I see are made by CR Spotless. I found this base model on Amazon for under $300 the last time I checked.

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 our post Washing Your Car with Hard Water? 3 Spot-Free Solutions for more information on what options may work best for you.

Using Distilled or DI Water for Cleaning Car Carpet and Upholstery

distilled water for carpet extractor

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.

Spray bottles

Whenever mixing any type of concentrated cleaning agent or chemical, it’s best practice to use distilled water. You don’t really want minerals found in hard water to mix with the cleaners you are using.

If you are a detailer that uses an isopropyl alcohol wipedown from time to time (prior to any type of paint correction), it’s a good idea to use distilled water for diluting the alcohol.

Distilled Water at Car Washes

If you find yourself at a self-service car wash, you may notice the ‘spot-free’ rinse option provided. Based on what I’ve read, these car washes usually purchase distilled water and store it in large tanks for this purpose.

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 Using Purified Water

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.

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