If you’ve been through a car wash lately, you’ve probably come across the term ‘spot-free rinse’ a time or two in that huge list of details.
I’ll admit it does sound like just a marketing gimmick, but there is actually something to it.
In this post, I’ll break down everything you need to know about water spots, and what makes a ‘spot-free rinse’, spot-free.
Spoiler alert: it comes down to the actual water itself.
What exactly is a spot-free rinse?
A spot-free rinse is the last step process of removing suds and excess water from a vehicle by using water that is free of impurities.
The water that is used is typically purified or softened using a process called deionization, reverse osmosis, or distillation in order to remove calcium and other minerals that cause water spots.
By spraying this type of water on a car at the end of the wash process, regular water that may be used for rinsing (that could contain minerals like calcium, lime, and magnesium) is rinsed off before drying can occur.
Any remaining water beads left behind on a vehicle after a spot-free rinse should not leave water spots when dry, which is why people prefer it.
At car washes, the ‘spot-free’ rinse water is generally just softened water that is stored in a tank separate from everything else.
Keep in mind, manually washing and hand drying a vehicle is the best way to avoid water spots, so even though a car wash may advertise a ‘spot-free’ rinse, it isn’t as foolproof as it sounds.
How to ensure a spot-free rinse at home
The most common device people use to remove impurities and achieve a spot-free rinse is called a water deionizer.
CR Spotless Portable Water Deionizer
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CR Spotless makes these in a few different sizes on Amazon; they’ve become pretty affordable in recent years and a great solution even for extreme cases.
These devices contain cartridges that include a deionizing resin that removes impurities like calcium. Below is a video to show you how everything works.
While I personally prefer the CR Spotless system for spot-free rinsing, other similar devices have popped up on the market like the Unger Rinse ‘N’ Go.
This device is a bit smaller and can support up to 11 washes before the resin filters need replacing, so you’re really better off with a more commercial solution like the CR Spotless.
The replacement filters for these CR units are relatively inexpensive and easier to find online as well.
Spot-free rinse products
Another common option for helping to achieve a ‘spot-free’ vehicle, is to use a product like Rain-X Spot Free Car Wash soap. While it’s best to always dry quickly, this product has water-sheening properties to help prevent spotting.
Rain-X Sot-Free Car Wash Soap
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If you’ve found it difficult to achieve a spot-free finish from home, hard water may be the culprit. A deionizer is great for washing cars, or you can install a whole-house water-softening system.
This will also make laundry, showers, and window cleaning spot-free as well.
You can read more about the process of softening hard water using deionization or distillation in my post Deionized vs Distilled Water for Detailing – When to Use It!
