How to Remove, Prevent and Avoid Water Spots on the Car When Washing

A gleaming, freshly washed car is a sight to behold, a testament to your care and pride in your vehicle. But one thing can deflate all the happiness and accomplishment you feel after washing your car — those dreaded water spots that seem to appear out of nowhere, destroying your car’s otherwise perfect finish.

This happens when you wash your car with a hose and you don’t completely dry it off after. Or perhaps when your car is parked nearby a sprinkler system and it dries on the surface. These drops turn into a dry-chalky substance which can be difficult to remove.

In this comprehensive guide, we’re going to demystify the world of water spots, offering you a guide to remove existing spots, and prevent their return altogether during the car-washing process.

Let’s start by understanding how these water spots are formed.

How Are Water Spots Formed?

When droplets of water containing contaminants such as dirt and minerals (primarily calcium and magnesium) dry on your car’s surface, it turns into a water spot.

There are actually 2 types of water spots according to what contaminant was in the water and how it dried.

The first type of water spot is a bonded mineral.

This is caused when the water droplets have a higher concentration of minerals which makes them harder to get rid of such as acid rain. These minerals tend to bond to the car’s surface and can even lead to corroding the paint’s clear coat.

This can leave small stains that will make your car’s paint look dull even after the contaminants have been removed. 

The second type of water spot is chemical etching.

This occurs when water droplets dry on your car’s surface because of the sun’s heat. This is where water spots on the paint are superficial and deep because it’s already etched. This is the most difficult water spot to remove because it can cause major permanent damage to the car if not handled correctly. 

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In general, water spots can etch the clear coat of your car, making it look dull and patchy. It can also make your car windows look dirty and old even after you cleaned them.

Although you can remove these stubborn water spots on your own, it’s best to have a professional detail service do the job for you so you can be sure that it’s done well.

Ways to Remove Water Spots

There are two different ways to remove water spots and yes, you can do it on your own. If you notice the water spots on your car right away, it would be much easier to remove. If you let it sit longer and ignore it, it’ll be much harder to remove.

In short, the longer it sits on your paint, the harder it is to remove. The good thing about removing superficial hard water spots is that it’s easy and you can do it all by yourself.

1. Diluted Wheel Acid

One effective way to remove water spots is by using diluted wheel acid. Since the pH of hard water is about 8-9, you can safely remove these stubborn spots with an acid cleaner.

Pro Tip: When using any acid cleaner, always wear protective gear. Wear a mask, gloves, and eye protection so that acid splatter won’t cause any health problems.

The acid balances out the alkaline pH of a water spot, thus removing it completely. To do this, get a spray bottle and dilute a wheel acid and distilled water with a ratio of 1:8 (1 part acid, 8 parts distilled water).

Before you spray diluted acid, wash the car thoroughly. Washing can eliminate some of the spots and contaminants on your car. A clean car can help you distinguish and separate hard water spots from regular dirt.

Once you’re done washing, shake up the bottle and spray the solution onto a small area. Then, scrub it with a clean microfiber towel wrapped around your index and middle finger and see if there’s a reaction.

If you see improvement, spray again or increase the strength of the dilution. If you don’t see any improvement after several attempts with increased strength, then machine polishing is the next step.

2. Machine Polish

Polishing your car’s paint is also an effective method to remove water spots. This will also help remove the etchings and any light scratches on the surface.

However, this is something that’s quite advanced so if you’re not able to execute this properly, it may do more harm to your car than good. It would be best to let a professional car detailer do this for you.

If you’re up for DIY-ing this, you will need a car polisher, a foam cutting pad, a foam polishing pad, and an effective compound. First, dab the compound on the polisher’s foam pad.

Next, using the machine polish, apply the product to the areas with a water spot in a circular motion until the stain disappears. Repeat the process on the parts of the car with the water spots.

You should know that in doing this, you will have most likely removed your car’s clear coat protective layer as well. The best thing to do is to reapply a layer of wax or sealer over your car to protect the finish.

How to Prevent Water Spots on the Car

Constantly removing water spots from your car’s surface can take a toll on your car’s paint over time. Why spend so much time and money removing water spots when you can prevent them?

Here are the different ways you can do to prevent water spots on your car’s surface.

1. Don't allow water to dry on your car's paint

If you let your car air dry, residues might get left behind. Although the liquid will eventually disappear, it will leave water spots, streaks, and deposits behind.

Water contains natural minerals which don’t really evaporate when air dried so it’s important to dry these droplets right away.

2. Use a deionizer when washing your car

The water that you use to wash your car contains a lot of minerals and impurities, including calcium, magnesium, sodium, copper, and iron.

When this water dries on your car’s surface, it can leave behind impurities and stubborn marks which can damage your car’s paint.

Using a deionizer helps remove these impurities in the water so as to avoid having water spots.

3. Use microfiber towels to fully dry your car's surface

After washing your car, it’s important to make sure the entire surface is dry so no minerals are left behind.

Using microfiber towels can help fully dry your car’s surface by soaking up any water droplets that may be left behind.

Always hand dry your car’s surface after you wash it or even after running it through an automatic car wash.

4. Have your car regularly washed and waxed.

A car wash and wax can help keep your car paint contaminant-free.

Plus, a wax or sealant acts as a shield between the mineral deposits in the water droplets and the clear coat so it’ll be easier for you to wipe any water droplets away before they dry.


Now that you know how to remove and avoid water spots on your car, the next time you wash your car your bubble of accomplishment will not be burst by the dreaded water spots.

In a nutshell, when droplets of water containing contaminants dry on your car’s surface, it creates water spots. There are two types of water spots: a hard water spot which is the most common one, a bonded mineral in which the water has a higher concentration of minerals, and an etching which is the worst of all because it’s already etched deep in the paint and has already caused damage.

Despite these being serious cases, they can easily be removed using two methods: using a diluted wheel acid and using a compound with a machine polish.

Instead of spending a lot of time and money on removing water spots, you can easily prevent them from forming and ruining your car’s paint. All you have to do is to use a deionizer when washing your car. And after that, make sure the water won’t dry on your car’s paint. You can use microfiber towels to fully dry them.

The best prevention of all is to have your car regularly washed and waxed by professional car detailers like River Islands Car Salon. Removing water spots from your car’s surface is a whole lot of work. If you’ve got no time to spare, you can always let car detailing experts take care of your car for you.

Contact us today for a free quote!

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