Does rain leave spots on a ceramic coating?

Yes, rain can leave hard water spots on your coating, these often appear as shiny spots with a white ring around them.

Hard water spots are formed when rain water droplets contain a lot of minerals. When the water evaporates, the minerals are left behind. Unfortunately, ceramic coatings can't prevent this, and the solution is the same for any car that gets them, which is to use a water spot remover.

You can make your own with white vinegar, but these days most of the major car care companies make products which are formulated to be safe on car paintwork. We would recommend buying one and following the manufacturer's instructions. 

Water spot removers are slightly acidic in order to break down the lime which comes from hard water spots. This is not a problem for ceramic coatings, which are very resistant to acid, meaning it should be easier to clean water spots from a car with a ceramic coating.

What this question is really about

This question usually comes up when owners notice marks or spots after rainfall and assume the ceramic coating should have prevented them. The concern is whether the coating is defective, worn out, or actually making the problem worse.

Does rain leave spots on a ceramic-coated car?

Yes, it can. Ceramic coatings do not stop water spots forming. What they do is make the surface easier to clean and more resistant to damage from those deposits.

Does a ceramic coating make water spots worse?

Yes and no. It can happen any shiny car, making it more of a shiny car problem than a ceramic coated car problem.

Water spotting can be worse on ceramic coated cars because they are hydrophobic, causing water to bead up. These beads are what focusses pollutants and causes the spot. 

Spotting isn't entirely caused by contaminants in the rain, they may well already be on your car in the form of dust and dirt. In the UK it's most common to see water spotting problems in the summer, when you have hot weather, mineral rich fine dust settles on the car, then you have a shower, the droplets collect this dust as they bead up, then the sun comes out again and bakes them on. Having a ceramic coating, which is self-cleaning, can help minimise the amount of contaminants on the car. 

A heavy shower may wash off most of the dust preventing spots; a very light shower might collect the dust, worsening the effect.

It should be noted, that like UV damage, water spots are a problem talked about because these products are sold worldwide. They may well be a common and serious issue in Texas or California, it's less of a frequent issue in Europe where we have less pollution, less sunshine, and less desert.

Why rain can still cause spotting

• Rainwater contains minerals and airborne contaminants
• As water dries, those minerals are left behind
• Water beads tightly on coatings, which can concentrate deposits as droplets dry

Why this is not a coating failure

Water spotting is a contamination issue, not a sign that the coating has stopped working.

• The coating is still bonded to the paint
• Chemical resistance is still present
• The marks are sitting on top of the coating, not replacing it

Where spotting is most noticeable

• Horizontal panels like bonnets, roofs, and boot lids
• Cars parked near industry, trees, or heavy traffic
• Areas where water pools before drying

What ceramic coating actually helps with

• Spots are usually easier to remove
• Reduced risk of etching compared with unprotected paint
• Less aggressive cleaning needed to restore the surface

How to deal with rain spots safely

• Rinse and dry the car if practical after heavy rain
• Wash using a pH-neutral, coating-safe shampoo
• Use targeted decontamination if mineral build-up develops
• Avoid scrubbing dry paint or deposits

Best-practice takeaway

• Rain can leave spots even on a ceramic-coated car
• This does not mean the coating has failed
• Ceramic coatings make spotting easier to manage, not impossible
• Regular, gentle washing prevents long-term build-up

Written by Danny Argent. Last updated 12/01/2026 18:11