Car windows - Hard Water removal - Success?


I focus right now mainly on residential window cleaning and some hard water removal for windows and shower doors. I keep hearing about how many people want to have their car windows fixed by removing the hard water spots from it.
Does anyone know if that’s a valid business? What are the potential pitfalls from it? Is it drastically different from the regular house window hard water removal?
I’m using the Mr. HardWater removal system. Any comments are appreciated, thanks!


Hard water on car windows? Pretty rare, No? I don’t see a lot of people using tap water and leaving their windows wet so it dries over time.


@GlassMD Yeah here in Medford, OR I’ve seen it a lot. I don’t know all the reasons why that is happening, but it’s certainly out there. Probably 3 times in the last week someone has asked me if I do car windows for hard water removal.
I guess it’s only in certain areas this is a problem.
Anyone with experience doing this?


Interesting. Well heck, glass is Glass- if I was asked, I would do it.

Definitely not something I would promote as that doesn’t seem to be an issue here.


As an offering of $5.00 or so for toll money, or as a business feature at $20.00?

If I had just packed up the gear from a gig ready to head to the next, it could be an easy $5 or $10, but I wouldn’t imagine it being a business venture.

How many spotted windshields would you have to do to actually earn a living?


@Garry yeah it doesn’t seem like that’d be enough to really get anything profitable. I might do it per house on whoever asks just for customer satisfaction but doesn’t seem so far that anyone has made a strong go of it.


Hey there London! Nice to see you in here. It’s Mike from Bend. I would try offering the service to existing customers. Just like we’re trained to do when heading to the door, be observant and note other things you could do for them. If you see spots on the car windows, offer to see what you can do for them and do a free sample. Choose on of the back windows that don’t matter much. If they like it, give them a quote. Find your ideal by making sure that your time is worth it first, then see at what price the people jump on it. Once you find a price range where 70% of people buy after the demo, you’ve got your new service and pricing as long as it’s making you enough money to accomplish your goals. If you can’t sell the service at a price point that makes it worth it, you drop the service. (This is a rule of thumb. I find that my pricing only wins 50% of bids but if I go any lower, I don’t make enough money per hour on the job to make it worth my time.)


It’s such a fine line…lol

Mike what’s your rate 2x -to 5x your normal rate per pane. When I was doing it I was at 4-5x, that was the line between profit or loss.

I might have to get back into it, it’s a constant question I’m asked.


I don’t see many cars with hard water spots, perhaps only if you park where sprinklers hit the car.
Ace Hardware Toilet Bowl Cleaner (hydrochloric acid active ingredient) is good to remove hard water spots from glass with a Super Fine steel wool pad but you have to neutralize it with with soapy water right after a chemical application (neutralize acid with alkali ) and rinse.
Mild Hard water spots on clear coat of a car can be removed by regular polishing (appropriate polishing compound and polishing pad), very bad cases of hard water spots on clear coated panels of a car can be treated like glass - acid chemical, then soapy water right away. Treat small area at a time and don’t let chemical dry on panel, rinse, rinse, rinse.
A friend of mine is a car detailer with 25 year experience, I got some education from him:)


I remember being told about a Caddy that had some simple HWS from a product used on the vinyl roof that was based on a sodiummetasilicate. No one knew how to remove them. They could have been quickly removed by a cerium polish. So all the glass was replaced at a couple thousand. Someone could have made five hundred in two hours. There IS big money in this idea if you get the right person. Not the right job. I just did a new store front the other day. A small fifty dollar job. The right person. An old customer and friend. The man before him was a dirty person, never cleaned anything, and would never have me clean his windows. When you find the right person you can make good money.



@henry That’s a good point, I think finding the right person is always going to be key no matter how much you’re making. There is going to be some kind of threshold as to what you can charge, and the higher the bid the lower the percentage of those who accept. I like the 70% acceptance rate because that tells me that I’m charging as high as I can so that we lose the cheapos but still low enough to get the majority of the market.


Yep. I totally agree!



Because we deal with silica stains here, there is no way to bid a window as just a multiple of regular cleaning. All work requires a 5k RPM polisher and lots of cerium. My rates start at $50/pane and so far have gone up to $300/pane (that was only one job lol and the glass was an $8000 pane). My target is $150/hr


Sound like we deal with same issues and we solve the issue with the same process.
I would say 80-85% of my first time clean I’m dealing with it. The thing that surprises me these are nice homes you would think they would remedy the issue at its source before it becomes a issue.

Thanks for your reply.


About car glass. Ran into this the other day. Stains on the glass are from car washes. Some boast soft water, but that is subjective, softeners must be maintained. Any who, used steel wool, Bar Keepers Friend, about every thing I had. Nothing. Water spots on windshield did not budge. Read on the web to use vinegar. Have not tried that yet; chimed in to relate that glass spotting is from car washes, very common. Pro detailers say, stay away from a car wash, but everybody does it. Cheers.


Vinegar won’t work to remove hard water stains that are beyond minimal staining in 95% of cases…this is from a guy with 25+ years owning an auto detailing company :wink:

Yes there are plenty of reasons to avoid the drive thru car wash… Pay a professional!


The pro who knows. Thanks, I figured. So…does the glass have to be buffed? What chem. to use then? By the way I tried CLR. It didn’t budge the stains either. But I used it on a shower door, worked great. Must be the sun bake- on factor. So…what to use for removing water stains from auto glass? (Henry?) WCS, can you answer this mystery? :anguished:


@LoveGlass This is what I heard when asking my hard water remover supplier:
“Usually I do it by hand with the sanding block and bronze wool pad. For the cleaner I use the Liquid Glass Polish or the powder but always test it in an inconspicuous place. Polishing with the polisher will also work but you need to be careful. Always make sure that there is not plastic in the glass, and make sure that the polisher speed is very slow. Then, use the glass sealer on it. I’m not sure how big of a market there is for it though.”


Great answer. Yeah, at window edges, if polisher rode or hopped onto paint, OOPS. Guess sane answer would be to use 3 inch disc around edges. There are some videos of body and detail guys polishing windshields, but they don’t share what they are using. Just fishing to see if what is used on storefront windows is also used on cars. Nice reading folks. Thank you.


Yeah, no wonder you are so good at windows…and details. Always appreciate your input.