Hard Water Spot Removal Techniques
by Greg NicholsHard water is an issue for much of the USA, and here in the Rocky Mountains of Utah we have some hard water that creates some difficulty in the removal of spotting (I frequently see 180-220 ppms and please refer to the chart below). Many people know that water spotting is unsightly and go to great lengths to prevent it and just plain avoid it………however sprinklers don’t care about your car. If you are quick with cleaning up these spots while they are fresh they won’t get set into or on the paint. Along with the minerals left behind on the paint, the water drops act like little magnifying glasses that “burn” the sun’s rays into the paint, this can cause deep etching.
When a water drop is deposited onto your car it carries with it a group of minerals; Calcium (Ca++), Sodium (Na+), Potassium (K+), and Magnesium (Mg++). Calcium and Magnesium are the most common. These minerals are in solution and cannot be easily seen until evaporation occurs. These minerals are then left behind (precipitate) as a mineral ring on the object. The hardness of the water is a product of the amount of minerals within the water. Any measurement above 15 ppm (mg/L) will leave spotting or the mineral precipitate. If you don’t have a ppm meter call the local water softening supplier and they can give you numbers, sometimes they report in grains…..1 grain is 17ppm IIRC.
| Classification | hardness in mg/L | hardness in mmol/L | hardness in dGH/°dH |
|---|---|---|---|
| Soft | 0–60 | 0–0.60 | 0–3.36 |
| Moderately hard | 61–120 | 0.61–1.20 | 3.42–6.72 |
| Hard | 121–180 | 1.21–1.80 | 6.78–10.08 |
| Very hard | ≥ 181 | ≥ 1.81 | ≥ 10.14 |
So what do you do if you have a car or any object that has water spots? In detailing we often try the least aggressive method first in ALL THINGS. I don’t care if you read that I used xyz product with abc application, you don’t know what I did to get to that point and it’s likely it won’t work BEST for your situation. “You don’t need to use a sledge hammer to drive a nail” Okay I’m climbing off my soapbox……. I would mix up some White Vinegar (if you like apple scent use apple cider vinegar 🙂 ) with distilled/filtered water in a 50/50 ratio, spray that onto the affected area and gently wipe. Why does this work? Vinegar is a weak acid and the water spots are basic (alkaline), so the acid will neutralize and break up the basic (alkaline) minerals. So if the vinegar doesn’t work, increase the ratio of vinegar until you get to straight vinegar if necessary. I have two bottles in my gear, one 50/50 and one 75/25 ready to go, its also good window cleaner. If the vinegar doesn’t “cut” it then its time to step up the acid strength. In a previous article I did on scum removal on a boat, the stronger acid I used on that gel coat has not been tested for automotive paints. So I have searched around for a safer product for automotive paint. I have been super pleased with the Chemical Guys Water Spot Remover, it works very quickly on tough spots that have sat for some time. I’ve taken some photos to show you just how effective this product is. I literally just applied it to a terry towel (use MF for paint) and gently wiped it on in back and forth motions and wiped it off with a clean damp towel. Wipe the area down with different clean sections of your damp cloth and don’t allow the remover to dry on the paint. I tried to show in photos the effectiveness on paint but all my photos just didn’t do it justice……so I used it on the shower glass……bingo nice photos to show effectiveness. You can also impress your significant other by cleaning the shower glass and earn some bonus points……….trust me I know!
Pretty thick coating of water spots
Another angle
Yes this bottle is on the other side of the glass
Nice clarity
Final shot
I have some experience that shows that wax will be removed, sealants are also mainly removed or greatly reduced, but that’s what they are suppose to do……a sacrificial layer of protection. I like it and use it on my daily driver which has an Opti Coat or Opti Guard coating applied. I’ve had it on for over 2 years without reapplication, my friend Chad Raskovich at Raskys Auto Detailing shares a bunch of info about this product just click the hyperlink. This coating takes the acid found in CG water spot remover incredibly well and it really protects against possible etching of the minerals into the paint. This coating will take the beating and not your paint. If you have to polish to remove etching you will be removing the coating NOT the clear coat at first. If you get aggressive you will start to work on the clear coat at that time. I have had to use the spot remover on two occasions without ill effects in my experience.
The other suggestion is to use the CR Spotless filtered water system when you wash your cars. While this can’t help against the rouge sprinkler, it makes it super easy to dry the car as you don’t have to towel it afterwards.
Good luck in keeping your car spot free, and if you get spots I hope this helps.
Cheers,
GREG
Excellent article! So the vinegar solution is wiped off immediately rather than left on the paint for a short time?
I have found Klasse AIO by hand to be effective at removing water spots, but I expect the vinegar solution may in fact be easier.
Why do car dealers wash cars and then leave them to dry in the sun? They should know better. I would never trust them with water spot removal.
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Thank you Greg for the article. However, I have a Question for you.
I have a new car Honda Accord 2013 about 6 months old, Unfortunately my car got covered in hard water spots from a near-by sprinkler system. I ignored the spots for sometime and since then have done a few simple washes and waxes, but the spots are still there under sun light and street light. My question: is will the Vinegar and water solution or the Chemical Guys Water Spot Remover dull my paint in any way? Also which is more abrasive and has the most potential to harm car paint or clear coat?
Thank you for your response!
Michael,
it is highly likely you will need more than vinegar, but I always try the least agressive first….go for straight vinegar on cool paint.
Yes these methods will remove the “wax” and decrease the durability of sealants. If you use the products properly they will be safe for paint. Work in small areas so the product doesn’t dry out on the paint. While these are still acid based products they generally safe in the hands of those that follow directions.
Cheers,
GREG
Upon suggestion from this blog, I started to use the Chemical Guys water spot remover, and I have to say it works phenomenally! Water spots on the windows and body (yes, sprinklers) are gone. My only comment is that the smell is vile. It has a vinegar-y vomit smell. I realize it has to have an acid ph to work, but seriously Chemical Guys, you’re uh, “chemical” guys. There’s no way to add a little pleasing scent to reduce my gag reflex?
Lee,
Are you using this in confinded spaces? I agree its a bit strong of an odor, but it works so well I just deal with it in well aired out areas.
Cheers,
GREG
Great article Greg!
How often is it safe to use Straight Vinegar and CG Water Spot remover? I have cars that are constantly covered with water spots and I want to make sure that I’m not damaging the car’s paint by using acid too often.
Thank you for your time and assistance!
Julian,
Vinegar I know of no known issues, other than if you allow it to dry on the surface. CG water spot remover is a bit stronger, just don’t allow it to also dry on the paint. Keep it from drying out. I’ve never had an issue of using it many times on clear coated paints. Its likely better to find a place to leave the car away from hard water spot sources.
Cheers,
GREG
Hey thanks for the tip on the vinager & water solution for water spots. I just finished a car with heavy spots. I tried mothers clay kit & it did a great, great job & leaving the owner speechless over his now ” new looking” old car. Now I’m ready to try your tip next. Its just another weapon in my quest to be the top Detailer in my area!!!. Stay tuned on my report on the solution & my next car with spots. Thanks I”m greatful for your tip. ” SHOW TIME 5000 “
Greg
Two years ago my neighbor bought his wife a new Pontiac Vibe. One day I noticed her washing her new car (something she never did with the old one for years) which was parked right next to my ’08 BMW 328. Needless to say by the time I ran out the door to move my car it was too late. The water had dried on the hood, roof, and trunk lid. I have tried the 100% white vinegar; it had no effect on the spots. I am ready to try something more aggressive. How long do I leave the ‘Guys WaterSpotRemover’ on the paint before I rinse?
Also, have you ever tried McGuiar’s products (M4716 or M3714) to compare?
Rick
Rick, Are you saying the spots are two years old? You might have to polish them off if that is the case as its likely they etched the clear coat some in that amount of time.
Keep chemical guys water spot remover wet/damp and work it over the effected area, do a test spot to figure out the time needed, but likely 2 min. Rinse well, ,and then neutralize it with a good car soap if you don’t need a 2nd application.
I’ve not tried the other products from Meguiars.
Cheers,
GREG
Thank you for your post. Very informative and helpful. I am grateful that you took the time and effort to help us.
Hi
I live in SLC so you know our hard water issues! I am always getting sprinkler spots. If I wash with the vinegar can I then rinse with the hose and dry then go have it washed and waxed or can I spray with vinegar wipe and go have it washed and waxed?
Thank you!
Ihave 2 cars that are have bad water spots most likely etched . What can I do to remove these water spots . Ihave tried everything straight vinegar to body clay and polishing compound . This has happened to both at an lax parking lot for about 2 weeks at a time with sprinklers running every night. help.
Robert,
Get some water spot remover by chemical guys https://www.detailedimage.com/Chemical-Guys-M31/Water-Spot-Remover-P194/16-oz-S1/ and give that a try. If that doesn’t work you will likely have to polish.
Cheers,
GREG
Have you ever used LA’s Totally Awesome to remove water spots from my Porsche that have been on for about 3 months. I tried straight white vinegar but it did not get it all out. Have you ever tried LA’s Totally Awesome? It was recommended by a local detailing company? Thanks.
JD
I have tried half water an half vinegar an it does not do anything
Hello Kyle try straight vinegar and see if it makes a difference if you can allow it to dwell but not dry on the paint that can help. If this doesn’t help there’s a pretty good chance they are not water spots but water etch.
Greg, thank you for these techniques.
The idea I take from this article is that cleaning the spot when it is still fresh will prevent them from get into the paint. I like it because it is true for cleaning in general and when applied should help me with other things.
I live in a high contaminant farming area, work at a sawmill, and my car lives in a car port open on two sides. I run my Jet Black Nissan through a free pressure wash at work each day. I find that Tutle Wax ICE brand Quick Detailer has enough solvents to clean off recent water spots (within 24 hours, sometime up to 3 days) and does not seem to seriously compromise the protection I have. I use it as my go-to water spot remover. If this does not get the spots out then I strip down to the clear coat with Sonax Paint Cleaner and start again with 2 coats of Polymer Net Shield (1 or 2 hours apart), then use Sonax Brilliant Shine Detailer for weekly maintenance. I review surface daily and use Wolfgang Uber Rinseless Wash for lighter cleaning, or Opti-Clean is the surface has higher dirt/grit content, and follow with a synthethic detailer like Meguire’s Ultimate Detailer, ChemGuys Synthetic Quick Detailer, or CG Speed Wipe as a drying aid. With above products I keep it clean with minimal swirls. Clay every 6 months using Adams Polishes Visco Elastic clay which I like as it’s easier to stretch – I work a full bar and stretch over middle 3 fingers using thumb and little finger to grip – never dropped after 5 full clayings – keep a spare just in case. Adams Detailing Spray used a clay lubricant and it all works great. Due to high dust environment I no longer use any products with carnauba – synthetics attract less dust. I have, but have discontinued using Sonax Liquid Wax for this reason as it has carnauba and silicone. In winter I also alternate Brilliant Shine Detailer with Opti-Seal which I use when the temps drop to freezing (Oregon) as Opti-Seal works as a drying agent in cold weather which helps dry rinseless solutions in the winter – I have applied as low as 28 degrees ahead of an ice storm and it worked great. After two years of buying lot’s of different products the above is finally working wells and has restored my sanity.
Do you recommend to use a hard water spot removal solution or go straight for a polish when a car is stained with this stubborn hard water.
Hello Charlice,
I always suggest the least aggressive first approach. I would wait to polish until it’s necessary, always try a good washing, then vinegar, then a dedicated water mineral remover. If the paint was ETCHED by the water spot you will likely have to polish then, but you likely won’t know that until after the aforementioned steps.
Cheers,
GREG
Hello, I used vinegar on light water spots but it didn’t work. Is there anything else easy that I could try ?
Or the only solution is to use a clay bar ? Thanks.
If you have tried Vinegar its time to step up to a dedicated WS remover like the suggestion in the article. IMO clay will make little to no improvement. At times the spots might be etched into the paint matrix when the paint was warm, you might have to warm up the paint some to open the matrix to reach the mineral deposits.
Cheers,
Thank you, but why some video show that claybar is working well to remove water spots ?
Example:
In that video you can see how much damage the clay is doing to the paint, that is black Chevy paint and needs a good polishing afterward. if you can chemically remove the spots you will likely not have to polish. least aggressive first. Agreed vinegar will not ALWAYS work, and I don’t think from the video he gave it a good try.
The logic, as you stated, seems simple. Acid neutralizing base. I am sure it would work well.
Thank you for suggesting to try vinegar to remove our water spot stains. I shall try that out before I move on to something more aggressive. My mother was telling me that we can buy water stain removers online that can guarantee a quick and easy removal but if your suggestion works then I won’t have to buy it.
Alicia, Always try the least aggressive first and then graduate your methods as needed.