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 I’ve seen people use to remove impurities and achieve a spot-free rinse from home is a portable deionizer like this one by CR Spotless you can pick up on Amazon.
I’ve dealt with those annoying hard water spots my whole life, and it really is a good investment if you have hard water at home and don’t want to deal with water spots.
These devices contain cartridges that include a deionizing resin and are great for everyday use. 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 been known to help prevent water spots when used correctly.
It’s basically a car soap formulated to sheen water off of your vehicle a bit better than most on the market.
If you’ve found it difficult to achieve a spot-free finish from home, hard water may be the culprit. While a deionizer is great for washing cars, installing a water softening system may be the best option.
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!