How quickly do water spots and etching form, from rainwater, potentially rainwater dripping from trees?

[TheZ06andFoxbody]

I park my 1991 Mustang outside. A couple days ago, I noticed that it had rained and there were what looked like cloudy water spots all over my car. Looked like dust had accumulated and then dried. I tried washing my car today, and upon looking closely there are water spots all over; with possible etching.


Could this have happened in two days from rainwater? The spots may have been there before but honestly I may not have noticed them. Only had the car a couple weeks. I’m worried I’ve now ruined the paint by parking the car outside. How likely is it that these were old spots? The car has a coat of Chadwick’s extreme ceramic coating and beads fantastically.

[Bruno Soares]

Are you sure it’s from rainwater and not a nearby sprinkler? Rainwater doesn’t often cause issues like that (though it’s not impossible) but sprinkler water will cause damage very fast depending on the water supply. Less than an hour and it could be etching.
Ceramic coatings are more prone to this due to aggressive beading which leads to fast evaporation and minerals left behind.

[TheZ06andFoxbody]

There aren’t any sprinklers in the area as far as I’m aware. It’s also weird because neither the car to my left or my right had any such spotting, just more minor stuff but similar. Maybe because I’m the only ceramic coated car in the area.

I actually just looked back and checked. Before I washed the car, there were really bad spots on the hood, roof, and front bumper. Now all the spots on the front bumper are gone, but there are still spots on the hood and roof. The front bumper was recently repainted so I’m guessing there were old spots on the hood and roof?

[Bruno Soares]

It could be old spots but when the car was ceramic coated those should have been removed.
Sometimes the heat on the paint due to sun will allow minerals to get into the clear coat and then when it’s cool you can’t clean it. Maybe try washing the car (perhaps one panel at a time) with the paint hot so you can try to remove the remaining spots. There are also products that are coating safe and you could try though I must say they’re mostly useless if it’s already at the point you describe.

[TheZ06andFoxbody]

It wasn’t professionally coated. There was no paint correction, the paint is full of horrific swirling and it’s just old. The guy just coated it in his driveway

[Bruno Soares]

Omg, so the spots could very well be under the coating and that’s why you’re struggling to remove them.
Sounds like you’ll need to paint correct the car, which will also remove the existing coating, then protect it again with your choice of LSP.

[TheZ06andFoxbody]

To be fair, all I’ve done so far is wash the car lol I did order some Carpro spotless so we’ll see if that works.

The spots don’t bother me, what bothers me is the idea that now that I bought this car I’ve ruined it by parking it outside and also that there are now new spots that I need to fix immediately to prevent further damage.

If the spots are old and aren’t getting worse, I’m not so worried. I can always correct them in the future.

[JDGolden]

. Maybe because I’m the only ceramic coated car in the area.

How would you even know that?

I agree with BSoares. I bet the spots are under the coating.

[TheZ06andFoxbody]

How would you even know that?

I agree with BSoares. I bet the spots are under the coating.

I don’t know it for sure, but the car to my left is an old minivan, and the car to my right is a Kia Sorrento, so it seems unlikely that they would be ceramic coated

[Loach]

Etching can occur very quickly, even with rainwater. It's going to depend on the environment and what's in the water when it's evaporating, but in my tests I've seen outer edge etching occur as soon as the bead fully evaporates from the panel on both some instances of rainwater and the water that's coming out of my hose. Spotting that isn't fully removed by any water spot remover, which needed polishing to tackle. In your case, if you're around trees that are dropping water on the paint during a rainstorm, this can be very nasty stuff that can do a lot of etching damage quickly to a more significant level compared to just regular rainwater.